Download Alberta Limber Pine Recovery Plan 2014-2019

Alberta Limber Pine Recovery Plan
2014–2019
Alberta Species at Risk Recovery Plan No. 35
Alberta Limber Pine
Recovery Plan 2014–2019
Prepared by:
The Alberta Whitebark and Limber Pine Recovery Team
Brad Jones, Alberta Environment and Sustainable Resource Development (Co-chair)
Robin Gutsell, Alberta Environment and Sustainable Resource Development (Co-chair)
Leonard Barnhardt, Alberta Environment and Sustainable Resource Development
Joyce Gould, Alberta Tourism, Parks and Recreation
Cyndi Smith, Parks Canada Agency
David Langor, Canadian Forest Service
Kelly Ostermann, Alberta Native Plant Council
September 2014
ISBN: 978-1-4601-1848-1 (On-line Edition)
ISSN: 1702-4900 (On-line Edition)
Cover Photos: Cyndi Smith (left); Jean Lussier (top right); Diana F. Tomback (bottom right)
For copies of this report, contact:
Information Centre – Publications
Alberta Environment and Sustainable Resource Development
Main Floor, Great West Life Building
9920 108 Street
Edmonton, Alberta, Canada T5K 2M4
Telephone (780) 422-2079
OR
Visit the Alberta Species at Risk Program’s web site at:
http://esrd.alberta.ca/fish-wildlife/species-at-risk/
This publication may be cited as:
Alberta Whitebark and Limber Pine Recovery Team. 2014. Alberta Limber Pine Recovery Plan
2014–2019. Alberta Environment and Sustainable Resource Development, Alberta Species at
Risk Recovery Plan No. 35. Edmonton, AB. 61 pp.
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DEDICATION
This recovery plan is dedicated to the memory of Dr. Narinder Dhir.
The late Dr. Narinder Dhir worked for more than 30 years guiding the progress of tree
improvement in Alberta. Narinder was hired by the Alberta Forest Service, Timber Management
Branch, in 1975 to develop a genetics and tree improvement program for the province. At the
program’s inception, he was the only staff member and had no facilities. Under his direction,
Alberta’s forest genetics and tree improvement program became very well-established. The
program that Narinder initiated is now mature, with 22 tree improvement projects, both private
and cooperative, approved and producing seed and stock for reforestation of provincial Crown
lands. The provincial program is supported by over 400 genetic field trials established on
approximately 75 test sites throughout the province, which is truly a testament to Narinder's
vision and passion. Narinder was always a strong advocate of tree gene conservation, which he
saw as a necessary stewardship responsibility that accompanied the increased domestication of
our forests that resulted from artificial regeneration and tree improvement. Narinder was one of
the early advocates and members of the ad hoc committee that was working on conservation
efforts for limber and whitebark pine prior to their endangered status and establishment of the
Recovery Team for both species.
-- Alberta Whitebark and Limber Pine Recovery Team, June 2014
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PREFACE
Albertans are fortunate to share their province with an impressive diversity of wild species.
Populations of most species of plants and animals are healthy and secure. However, a small
number of species are either naturally rare or are now imperiled because of human activities.
Recovery plans establish a basis for cooperation among government, industry, conservation
groups, landowners and other stakeholders to ensure these species and populations are restored
or maintained for future generations.
Alberta’s commitment to the Accord for the Protection of Species at Risk and to the National
Framework for the Conservation of Species at Risk, combined with requirements established
under Alberta’s Wildlife Act and the federal Species at Risk Act, has resulted in the development
of a provincial recovery program. The overall goal of the recovery program is to restore species
identified as Threatened or Endangered to viable, naturally self-sustaining populations within
Alberta. The policy document Alberta’s Strategy for the Management of Species at Risk (2009–
2014) provides broader program context for recovery activities.
Alberta species at risk recovery plans are prepared under the supervision of the Species at Risk
Program, Alberta Environment and Sustainable Resource Development. This often includes
involvement of a recovery team composed of various stakeholders including conservation
organizations, industry, landowners, resource users, universities, government agencies and
others. Membership is by invitation from the Executive Director of the Fish and Wildlife Policy
Branch and is uniquely tailored to each species and circumstance. Conservation and management
of these species continues during preparation of recovery plans.
The Executive Director of the Fish and Wildlife Policy Branch provides these plans as advice to
the Minister of Environment and Sustainable Resource Development. Alberta’s Endangered
Species Conservation Committee also reviews draft recovery plans and provides
recommendations on their acceptance to the Minister. Additional opportunities for review by the
public may also be provided. Plans accepted and approved for implementation by the Minister
are published as a government recovery plan. Approved plans are a summary of the Ministry’s
commitment to work with involved stakeholders to coordinate and implement conservation
actions necessary to restore or maintain these species.
Recovery plans include three main sections: background information that highlights the species’
biology, population trends, and threats; a recovery section that outlines goals, objectives, and
strategies to address the threats; and an action plan that profiles priority actions required to
maintain or restore the Threatened or Endangered species. Each approved recovery plan
undergoes regular review, and progress of implementation is evaluated. Implementation of each
recovery plan is subject to the availability of resources from within and from outside
government.
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TABLE OF CONTENTS
PREFACE ................................................................................................................................................................. IV
TABLE OF CONTENTS ........................................................................................................................................... V
EXECUTIVE SUMMARY ................................................................................................................................... VIII
1.0 INTRODUCTION .................................................................................................................................................1
1.1 PROVINCIAL AND FEDERAL STATUS ....................................................................................................................1
1.2 RECOVERY PLAN AND RECOVERY TEAM .............................................................................................................1
2.0 LIMBER PINE BIOLOGY ..................................................................................................................................2
2.1 GENERAL BIOLOGY .............................................................................................................................................2
2.2 GENETICS............................................................................................................................................................. 3
2.3 HABITAT .............................................................................................................................................................. 6
2.4 DISTRIBUTION, POPULATION SIZE AND TRENDS ..................................................................................................7
2.5 ECOLOGICAL ROLE ..............................................................................................................................................9
2.6 CLARK’S NUTCRACKER BIOLOGY........................................................................................................................ 9
3.0 THREATS AND LIMITING FACTORS .......................................................................................................... 11
3.1 OVERVIEW ......................................................................................................................................................... 11
3.2 THREAT ASSESSMENT ........................................................................................................................................ 11
3.3 WHITE PINE BLISTER RUST................................................................................................................................ 12
3.4 MOUNTAIN PINE BEETLE ................................................................................................................................... 15
3.5 CLIMATE CHANGE ............................................................................................................................................. 17
3.6 FIRE ................................................................................................................................................................... 19
3.7 LOSS OF PRIMARY SEED-DISPERSING AGENT ..................................................................................................... 20
3.8 OTHER THREATS ................................................................................................................................................ 20
3.9 BIOLOGICALLY LIMITING FACTORS ................................................................................................................... 21
4.0 CRITICAL HABITAT ........................................................................................................................................ 22
5.0 RECENT RECOVERY AND CONSERVATION EFFORTS ........................................................................ 22
6.0 INFORMATION GAPS AND RESEARCH NEEDS ....................................................................................... 24
6.1 HIGH PRIORITY .................................................................................................................................................. 24
6.2 MODERATE PRIORITY ........................................................................................................................................ 26
6.3 LOW PRIORITY ................................................................................................................................................... 27
7.0 RECOVERY STRATEGY ................................................................................................................................. 27
7.1 BIOLOGICAL AND TECHNICAL FEASIBILITY OF RECOVERY ................................................................................ 27
7.2 GUIDING PRINCIPLES ......................................................................................................................................... 28
7.3 RECOVERY GOAL............................................................................................................................................... 29
7.4 RECOVERY OBJECTIVES ..................................................................................................................................... 30
7.5 RECOVERY STRATEGIES..................................................................................................................................... 32
8.0 ACTION PLAN ................................................................................................................................................... 33
8.1 POPULATION MONITORING ................................................................................................................................ 33
8.2 PROTECTION OF LIMBER PINE STANDS AND INDIVIDUAL TREES........................................................................ 34
8.3 CONSERVE GENETIC RESOURCES, SCREEN, PROPAGATE AND DEPLOY RUST-RESISTANT LIMBER PINE ............ 35
8.4 HABITAT AND NATURAL REGENERATION MANAGEMENT ................................................................................. 36
8.5 INFORMATION AND OUTREACH .......................................................................................................................... 37
8.6 RESEARCH ......................................................................................................................................................... 38
8.7 PLAN IMPLEMENTATION, MANAGEMENT AND ADMINISTRATION ...................................................................... 38
8.8 RESOURCE ACQUISITION ................................................................................................................................... 38
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9.0 IMPLEMENTATION SCHEDULE AND COSTS ........................................................................................... 39
10.0 SOCIO-ECONOMIC CONSIDERATIONS ................................................................................................... 47
11.0 LITERATURE CITED ..................................................................................................................................... 49
LIST OF FIGURES
Figure 1. Known range of limber pine in Alberta. .......................................................................... 8
LIST OF TABLES
Table 1. Limber pine threat assessment. ....................................................................................... 11
Table 2. Summary of current and recent conservation efforts in Alberta. .................................... 23
Table 3. Implementation table for limber pine recovery actions including cash and in-kind
contributions. ................................................................................................................................ 40
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ACKNOWLEDGEMENTS
The recovery team would like to acknowledge various individuals for their contribution to the
successful completion of this plan. Erica Samis (Alberta Environment and Sustainable Resource
Development) initially co-chaired the team and was integral in formulating this document.
Laurie Hamilton was an original member of the team and participated in the initial stages of
recovery planning on behalf of the Alberta Native Plant Council. The team greatly appreciated
reviews of the plan from the following people: Vern Peters (The King’s University College),
Anna Schoettle (USDA Forest Service, Rocky Mountain Research Station), as well as input from
Mike Flannigan (University of Alberta) on the effects of climate change. In addition, the limber
pine plan is closely modelled after the recently-completed whitebark pine recovery plan, which
benefited from review from the following individuals, who we also acknowledge here: Diana
Tomback (University of Colorado Denver), Peter Achuff (Scientist Emeritus, Parks Canada
Agency), Diane Casimir (Parks Canada Agency), and Michael Murray (B.C. Ministry of Forests,
Lands, and Natural Resource Operations). The following Alberta Environment and Sustainable
Resource Development staff also reviewed and made helpful comments on this draft plan and/or
the whitebark pine plan: Pat Fargey, Ken Greenway, Brooks Horne, Naomi Jehlicka, Dan Lux,
and Erica Samis. Nyree Sharp provided thorough editorial services, and Drajs Vujnovic and
Marge Meijer (Alberta Tourism, Parks and Recreation) very helpfully compiled and mapped
known limber pine observations.
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EXECUTIVE SUMMARY
Limber pine (Pinus flexilis) grows in the Montane and lower Subalpine natural subregions of
western Alberta. Its range in Alberta spans from the U.S. border to Abraham Lake, at 52.25
degrees latitude. Limber pine is a slow-growing, long lived species, often reaching 400 years or
more in age; the oldest individual recorded in Alberta is approximately 642 years old. The tree
can grow up to 12 m in height and 60 cm in diameter. On exposed sites limber pines take on a
bent, twisted appearance, and at higher elevations they can assume a stunted, krummholz growth
form. Limber pine performs several important ecological functions and is considered both a
keystone and a foundation species. Clark’s nutcracker (Nucifraga columbiana) is the primary
seed disperser for limber pine, but the relationship is not obligate, as it is in the case of the
closely related whitebark pine (Pinus albicaulis Engelm.) where the cones are opened only by
the nutcracker.
On October 24, 2008, the Minister of Alberta Environment and Sustainable Resource
Development supported the listing of limber pine as Endangered under Alberta’s Wildlife Act.
This designation was due to an observed and projected population decline across the species’
provincial range, caused by the introduced white pine blister rust (Cronartium ribicola) and
outbreaks of the mountain pine beetle (Dendroctonus ponderosae). The Committee on the Status
of Endangered Wildlife in Canada is currently reviewing a status report for limber pine in
Canada.
In September 2009, the Alberta Whitebark and Limber Pine Recovery Team was established, in
part to produce a recovery plan for limber pine in Alberta. The recovery team includes
representatives from Alberta Environment and Sustainable Resource Development; Alberta
Tourism, Parks and Recreation; Canadian Forest Service; Parks Canada Agency; and the Alberta
Native Plant Council. The Alberta Forest Products Association was also invited to join the team,
and although not active in developing the recovery plan, it has been kept advised of progress and
has reviewed the draft plan.
The recovery plan has been prepared to guide the management of this Endangered species over
the next five years and beyond. The long term goal of this plan is:
“To conserve existing populations and habitat while restoring populations across the species’
current and historical provincial range in sufficient numbers to continue functioning in its
ecological role.”
In line with this goal, four objectives have been established:
1. Reduce the direct mortality of limber pine;
2. Develop and introduce white pine blister rust-resistant strains;
3. Conserve genetic diversity; and
4. Manage habitat and natural regeneration.
To help achieve this goal and meet the objectives, nine general strategic approaches have been
proposed:
1. Population monitoring;
2. Tree and stand protection;
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3.
4.
5.
6.
7.
8.
9.
Conservation of genetic resources;
Habitat management;
Education and outreach;
Research that will elucidate or facilitate recovery actions;
Plan implementation, management and administration;
Resource acquisition; and
Collaboration among agencies, jurisdictions and stakeholders.
Each general approach will be implemented by actions delineated in this report. The overall
intent is to protect and manage limber pine and reduce the anthropogenic impediments to its
survival. This recovery plan will undergo periodic review during its designated life span of five
years, after which it will be updated as needed.
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1.0 INTRODUCTION
1.1 Provincial and Federal Status
Limber pine (Pinus flexilis) has been designated as an Endangered species under Alberta’s
Wildlife Act since 2009 (Government of Alberta 2012). The Endangered designation was based
on an ongoing and projected population decline across the species’ provincial range, caused by
the introduced white pine blister rust (Cronartium ribicola, Order Pucciniales) and mountain
pine beetle (Dendroctonus ponderosae Hopkins, Coleoptera: Curculionidae: Scolytinae). The
Limber Pine Initial Conservation Action Statement specified that a recovery plan would be
prepared and that sufficient new resources should be made available to support recovery
planning. The action statement advised that Alberta Environment and Sustainable Resource
Development (ESRD) should enhance programs to carry out cone collection (both to find and
propagate rust-resistant trees and to conserve genotypic diversity), inventory, monitoring, and
research into the use of the anti-aggregation pheromone, verbenone, to protect trees from
mountain pine beetle.
As of the writing of this recovery plan, the species has not been assessed nationally. The
Committee on the Status of Endangered Wildlife in Canada (COSEWIC) is reviewing a status
report for limber pine in Canada (Achuff, pers. comm.). If a legal status of Endangered or
Threatened under Schedule 1 of the Species at Risk Act is eventually assigned to limber pine
nationally, then a national recovery strategy would be developed.
1.2 Recovery Plan and Recovery Team
The purpose of this recovery plan (herein, the Plan) is to provide clear direction for recovery
actions for the limber pine in Alberta. The Plan was prepared by The Alberta Whitebark and
Limber Pine Recovery Team, which is composed of individuals knowledgeable about the
species, organizations influential in the management and recovery of the species, and
stakeholders who may be affected by recovery actions for the species. Recovery team members
were selected to provide informed and diverse input to the development of the plan. Although the
recovery team works with both pine species, this plan is focused only on limber pine.
The Minister of ESRD created the Alberta Whitebark and Limber Pine Recovery Team in
September 2009; the recovery team receives operational guidance and approval from the
Executive Director of the Fish and Wildlife Policy Branch. The recovery team’s primary
responsibility is to advise the Minister of ESRD on the management of this species by outlining
recovery strategies and actions in the recovery plan. ESRD oversees the implementation of the
recovery plan by facilitating and encouraging the involvement of appropriate and interested
parties, including members of the team. The team co-chairs are responsible for evaluating and
reporting on the progress of recovery actions, and updating the recovery plan at the end of its
lifespan; the recovery team may be reconvened to assist with the update as necessary.
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2.0 LIMBER PINE BIOLOGY
2.1 General Biology
Limber pine is a slow-growing, long-lived species. The oldest tree on record in Alberta is 991
years old, from Siffleur Ridge (Sauchyn 2010), and trees between the ages of 200 and 450 years
are not uncommon in the region (Webster and Johnson 2000; Sauchyn 2010). Limber pine can
grow up to 12 m high and 60 cm diameter in Canada (Farrar 1995). The bark on young trees is
smooth and pale grey, growing to dark brown and plated as the trees age. As limber pine is
typically exposed to harsh growing conditions, it often develops a bushy, branched appearance
with an irregular crown that extends along most of the tree’s length (Alberta Sustainable
Resource Development and Alberta Conservation Association 2007). Old branches tend to droop
with their ends upturned, while young branches are particularly tough and flexible — hence the
name “limber” pine (Farrar 1995). Needles occur in bundles of five and are 3–7 cm long. Limber
pine has a deep, spreading root system to provide an anchor against wind and take advantage of
more hospitable spaces in the substrate in which it grows (Steele 1990).
On exposed sites, wind can sculpt limber pines to give them their iconic bent and twisted
appearance. At the most extreme, limber pine can take on a krummholz growth form where it
grows horizontally along the ground. Limber pine may be easily mistaken for whitebark pine
(Pinus albicaulis Engelm.), as their growth forms and bark can be similar when growing in the
open, and they have overlapping distributions in Alberta south of about 52° north. Limber pine
generally occurs at lower elevations, but the most reliable method of differentiating the two
species is through male and female cone characteristics: limber pine female cones are light
brown and cylindrical, while whitebark pine female cones are dark purple to brown and almost
round in shape. Also, the mature seed cones of limber pine are elongate and change from green
to light brown, while those of whitebark pine are ovoid and purplish. Limber pine drops its cones
after seed dispersal, while whitebark pine cones remain on the tree.
Limber pine has a reproductive cycle similar to that of other pines, taking two years from cone
initiation to seed maturity. Mature trees (over 50 years old) produce both male and female
reproductive structures on the same tree annually, and produce large cone crops every two to
four years (Peters and Gelderman 2011; D. Langor unpublished data). Female cones are borne
higher and male structures borne lower on the crown of the tree. Pollination from wind occurs
between June and July in the first year of cone development, and fertilization occurs the
following spring or early summer (Steele 1990). Sites that differ in elevation do not necessarily
have overlapping pollination periods, which may restrict gene flow (Schuster et al. 1989). Once
fertilized, the cones and seeds mature rapidly and are fully mature in late August or early
September of the same year. Mature cones are large (8–20 cm long) and drop the large (10–15
mm) wingless seeds while still on the tree. Once released from the cones, seeds remain viable for
at least five years (Johnson 2001)
Seeds are removed and cached primarily by Clark’s nutcracker (Nucifraga columbiana) and red
squirrels (Tamiasciurus hudsonicus Erxleben) (Benkman et al. 1984; Tomback and Linhart
1990). However, squirrels tend to harvest cones before seeds are ripe, and also function as predispersal seed predators, and therefore likely contribute little to dispersal (Benkman et al. 1984;
2
Peters and Vandervalk 2009). Consequently, Clark’s nutcracker is the primary dispersal agent for
limber pine (see Section 2.6). Seeds that are cached but not consumed remain viable for up to
two years (Webster and Johnson 2000). Several other rodent species collect and cache mature
seeds, which can lead to successful regeneration (Tomback et al. 2005); however, these caches
are often close to the parent tree, and are not helpful for long-range dispersal. Nevertheless,
several granivorous mammals play key roles in secondary dispersal in disjunct portions of limber
pine range where nutcrackers are either rare or absent (Tomback et al. 2005). In such systems,
secondary caching results in more favourable seed placement and germination than nutcracker
caching. The role of secondary dispersal has received little attention through the core range of
limber pine, but may play an important role in natural regeneration if nutcracker-assisted
dispersal declines in the future.
Clark’s nutcracker is important to the survival of limber pine as it makes it possible for
recruitment of new limber pine stands. Often multiple limber pine seeds germinate in close
proximity to each other within a Clark’s nutcracker’s cache, forming a multi-stemmed cluster.
These seedlings experience some benefits, such as wind protection and more efficient nutrient
acquisition; however, once they are established, negative interactions associated with crowding
and competition for nutrients and moisture may outweigh positive benefits and result in
misshapen, multi-trunk trees with diminished reproductive capacity (Feldman et al. 1999).
Limber pine seedlings are poor competitors with other plant species, and use a life history
strategy of persistence through harsh conditions rather than direct competition (Schoettle 2004a).
2.2 Genetics
There is limited information available on genetic variation and population differentiation for
limber pine, particularly for adaptive traits. Most studies of genetic variation have used
molecular techniques, which likely underestimate population differentiation and genetic variation
for critical adaptive traits important for conservation work. Because of the biology, ecological
role, and the nature of the threats associated with limber pine, recovery of this species will not be
successful without some of this basic information and genetic intervention.
2.2.1 General Structure of Genetic Variation
Limited information on genetic differentiation in limber pine has been reported using allozymes
(variant forms of enzymes, often used as molecular markers in genetic analyses; Schuster et al.
1989; Jorgensen et al. 2002) and mitochondrial DNA (Mitton et al. 2000). These studies have
served to document levels of genetic variation for the species, the distribution of variation within
and among populations, and the role of biogeographic processes (e.g., glaciation) in determining
current patterns of variation.
Based on 30 limber pine populations throughout the species’ range, Jorgensen et al. (2002)
reported that the expected heterozygosity of limber pine (having dissimilar pairs of genes for any
hereditary characteristic) was higher than for some other pine species, including whitebark pine,
but similar to other widespread North American pine species. Differentiation among limber pine
populations was also high compared to other pines and conifer species, which exhibit the most
variation (90%) within populations rather than among populations. However, this study also
characterized limber pine as having significant inbreeding. Total genetic diversity found among
3
populations was significant; however, despite a similar reproductive strategy to whitebark pine,
subpopulation differentiation based on molecular analysis appears to be somewhat finer scaled.
Based on genetic distance analyses, three broad geographic regions of genetic similarity are
recognized for limber pine: a Northern Rocky Mountain region (which includes all Alberta
populations), a Basin and Range region and a Utah Rocky Mountain region (Jorgensen et al.
2002). A weak but significant correlation was found between genetic and geographic distance for
pooled populations from the Utah and Northern Rocky Mountain regions, but this correlation
was absent for Basin and Range populations. Populations in the Northern Rocky Mountains and
Basin and Range region had significantly higher levels of within-population genetic diversity
than those of the Utah Rocky Mountains. Inbreeding was highest in the Basin and Range and
Utah Rocky Mountain populations and significantly lower in the northern Rocky Mountain
populations, likely indicating higher out-crossing and gene flow in the latter. Northern Rocky
Mountain populations showed lower genetic diversity overall than the other regions (Bower et al.
2011) which would be consistent with theories of more recent post-glacial migration in these
areas.
Mitton et al. (2000) found that the majority of mtDNA haplotypes were highly restricted in
range, suggesting seven possible glacial refugia south of the glacial front in New Mexico,
California, Arizona, Colorado, the Great Basin and Wyoming, from which limber pine may
subsequently have spread. Based on this study, the distance between current detectible
populations is commonly in the range of 150 km, suggesting that gene flow through windmediated pollen dispersal is effective but it is restricted for seed even when assisted by Clark’s
nutcracker.
Although these studies are informative and provide some of the information required to make
decisions for restoration efforts, they focus more on neutral rather than adaptive genetic variation
and, therefore, have a tendency to underestimate local adaptive variation (Bower and Aitken
2008), a knowledge of which is necessary for effective gene conservation, seed transfer, tree
breeding, and restoration work.
The effect of seed dispersal by Clark’s nutcracker on kinship and the genetic structure of limber
pine was investigated by Schuster and Mitton (1991). They found that, for an isolated limber
pine population in northeastern Colorado, 17.6% of multi-trunk clusters contained more than one
genotype, as estimated from allozyme electrophoresis analyses of 10 loci. This would suggest
that at least that proportion of caches made by nutcrackers contained seeds from multiple trees.
Comparison of observed versus expected distribution of genotypes indicated that, where more
than one genotype occurred in a cluster, the distribution most closely conformed to that of halfsibs, but relatedness varied widely among clusters.
In 2004, field sampling was completed to assess the current and potential impacts of white pine
blister rust on the genetic diversity of limber pine. Although mtDNA was extracted and partially
characterized (D. Langor unpublished data), this work is currently on hold pending new
resources. This does provide a modest starting point to examine genetic diversity within the
species in Alberta.
4
2.2.2 Adaptive Genetic Variation
Common garden studies (replicated genetic trials established across test sites using range-wide
population sampling) to determine population differentiation for phenotypic traits related to local
adaptation, such as the studies established and reported for whitebark pine by Bower and Aitken
(2008), are largely absent for limber pine. One recent common garden study for limber pine is
reported (Reinhardt et al. 2011), which examined the performance of a high and low elevation
seed source (in this case within approximately 200 m elevation) planted across three sites
representing an elevation gradient of over 500 m in Colorado. This study found seed source
variation for survival. Differences were also noted for plant dry mass, shoot : root ratios,
photosynthesis, carbon balance, and stomatal (pore) conductance, which were greater for the
low elevation seed source. Significant genotype by site interaction was reported for plant dry
mass. The authors concluded that variation related to seed source in limber pine may have
important implications for adaption to climate change. This will also apply to adaptation to
climate displacement that occurs during seed transfer in the course of species recovery work.
Schoettle and Rochelle (2000), looking at morphological trait variation in populations over a
range of approximately 1700 m in elevation and 10.2ºC in mean July daily temperature (22.8ºC
and 12.6ºC at low and high elevations, respectively), found no notable variation in tree, leaf or
shoot morphology. However, there was significant variation in stomatal density, which decreased
with increasing elevation and decreasing mean daily July temperature of source. This pattern
could reflect an acclimation response to reduce water loss at high elevations, which may also be
important in seed transfer and recovery work.
Schuster et al. (1989) examined pollination phenology at eight sites along an elevational transect,
and allozyme variation in two populations at the upper and lower extents of the transect in the
Rocky Mountains of Colorado, to investigate the level of fine-scale interpopulation gene flow.
They determined that pollination phenology was strongly affected by site elevation, and that
populations varying by more than 400 m in elevation did not have overlapping pollination
periods but were synchronous within populations to female (cone) flower receptivity. A
difference of one month in initiation of pollen release between upper and lower elevation
populations is sufficient to restrict interpopulation gene flow. Using allozymes, they also
determined that there were significant gene frequency differences between the upper and lower
elevation populations, which is expected based on pollination timing differences among
populations; however, the level of gene flow between the upper and lower elevation populations
was higher than might have been expected, at an estimated 11.1 migrants per generation. This
suggests that stepping-stone pollen transfer may be occurring between populations along the
transect as well as substantial gene flow through bird-mediated seed dispersal.
In summary, genetic studies to date suggest:
1) several glacial refugia with subsequent migration and colonization after glacial retreat
(Mitton et al. 2000; Jorgensen et al. 2002);
2) inhibited gene flow resulting from geographic isolation of small populations, and the
potential for population differentiation through gene loss as a result of genetic drift
(Schuster et al. 1989; Mitton et al. 2000; Jorgensen et al. 2002);
3) generally elevated inbreeding (Jorgensen et al. 2002), and localized inbreeding as a result
of cluster caching by Clark’s nutcracker (Schuster and Mitton 1991); and
5
4) indications of significant among-population genetic variation for adaptive traits.
These results are similar to those for whitebark pine (Jorgensen et al. 2002), except for the trend
toward greater among-population variation at the subregional rather than regional level in limber
pine, which may be a result of greater population fragmentation on the landscape. Although there
is little study of, or evidence for, variation in quantitative and adaptive traits, measures of gene
flow indicate that genetic selection may be operating to maintain among-population variation
(Schuster et al. 1989; Schoettle and Rochelle 2000).
A greater sampling intensity may be required for assessing and conserving genetic diversity in
limber pine than for whitebark pine. The phenotypic phenology and allozyme differences related
to elevation, and other molecular measures of genetic variation, indicate greater subregional
variation amongst populations in limber pine than in whitebark pine. If this phenotypic
phenological and molecular variation is related to adaptive genetic variation, greater care may be
necessary in seed and stock transfer than will be necessary for whitebark pine.
2.2.3 White pine blister rust susceptibility and genetic resistance
All limber pine stands in Alberta examined for white pine blister rust incidence have shown
infection, although the degree of infection is highly variable. In highly infected stands there can
be individuals that have not been infected; these are potentially resistant trees that may aid in
recovery strategies. No studies of genetic resistance patterns or mechanisms have been
conducted in Canada. Recent white pine blister rust resistance work with limber pine in the U.S.
by Schoettle et al. (2014), reports the presence of an inherited stem-symptom free trait attributed
by them to a single dominant resistance gene. This resistant allele appears to be unique from
similar alleles found in other five needle pines and was found at reasonably high frequencies in
the southern Rocky Mountains.
2.3 Habitat
Limber pine occurs in a variety of habitats, from gravel creek beds and gently rolling terrain to
ridge tops and steep cliffs. These sites are predominantly in the Montane and lower Subalpine
natural subregions of Alberta (Downing and Pettapiece 2006; and see Alberta Sustainable
Resource Development, Alberta Environment, Alberta Community Development and
Agriculture and Agri-Food Canada 2005), where limber pine spans a broad elevational range of
between 1 200 and 2 000 m. Lower-elevation sites are found farther east, near the Bow and Belly
rivers and in the Porcupine Hills. Treeline sites have been observed in and around the Bow
Valley and Waterton Lakes National Park. Sites tend to have southerly and westerly aspects or
be on exposed ridge tops. Limber pine can grow in shallow soils on xeric, rocky sites where
conditions are not suitable for the establishment of other tree species. Bedrock material is
typically calcareous with well-drained Brunisolic and Regosolic soils (Timoney 1999). Limber
pine is highly tolerant of windy, frosty, and dry conditions, moderately tolerant of snowpack and
warm, nutrient-deficient conditions, but has little tolerance of shade and moisture (Steele 1990;
Government of British Columbia 2009).
6
Limber pine typically grows in open sites, either in discrete stands or as single trees. Single trees
occur on drier sites but limber pine tends to be limited to early succession on more mesic sites
(Schoettle 2004a). Limber pine is able to colonize new habitat created by fire and other
disturbances, because the seeds that have been cached by Clark’s nutcracker (Rebertus et al.
1991) are able to germinate and establish before those of other conifer species, which are winddispersed (Tomback et al. 1993). In areas where there is soil development, limber pine may act
as an early seral species, providing the site conditions for other species to establish, and then may
eventually be replaced through succession (Baumeister and Callaway 2006). In Alberta, limber
pine is often associated with other coniferous tree species such as Engelmann spruce (Picea
engelmannii), lodgepole pine (Pinus contorta), Douglas fir (Pseudotsuga douglasii) and, at some
sites in southwestern Alberta, whitebark pine.
2.4 Distribution, Population Size and Trends
Limber pine has a broad range in North America, primarily following the slopes of the Rocky
Mountains but also extending west through to California. The distribution occurs from
approximately 52° N near the Kootenay Plains in Alberta to 33° N in southern California,
Arizona and New Mexico (Tomback and Achuff 2010). In Canada, the vast majority of limber
pine occurs in Alberta, with only a few known isolated pockets in southeastern British Columbia
(Alberta Sustainable Resource Development and Alberta Conservation Association 2007). Pollen
records indicate that limber pine has likely occurred in Alberta for at least the past 10 000 years
(MacDonald 1989). The majority of the provincial population is found along the eastern slopes
of the Rocky Mountains (Figure 1); the range occurs in the Montane Natural Subregion and the
lower portions of the Subalpine Natural Subregion, with minor occurrences in the western
portion of the Foothills Parkland Natural Subregion (Downing and Pettapiece 2006).
Although the provincial range of limber pine is generally known (Figure. 1), the lack of
inventory makes population estimates difficult and reported numbers vary greatly. The extent of
occurrence for limber pine in Alberta is estimated to be between 16 000 km2 (Alberta
Sustainable Resource Development and Alberta Conservation Association 2007) and 35 568 km2
(Achuff, pers. comm.). Area of occupancy varies from estimates based on the typical 2 km x 2
km grid at 1 460 km2 (Achuff, pers. comm.) to just 80 km2 based on survey crew estimates
(Alberta Sustainable Resource Development and Alberta Conservation Association 2007).
Subsequently, the Alberta population of mature trees greater than 10 cm in diameter (the size by
which reproductive maturity is assumed) is estimated to be between 44 400 000 (Achuff, pers.
comm.) and as low as 1 940 000 (Alberta Sustainable Resource Development and Alberta
Conservation Association 2007). The large discrepancy between these two population estimates
underlines the need for an inventory in order to adequately assess population trends.
Studies in Alberta indicate that most populations are rapidly declining as a result of mortality
from white pine blister rust infection, which exceeds the rate of limber pine recruitment,
especially in the southern portion of the Alberta range (Smith et al. 2013b). In the northern
portion of the Alberta range, limber pine populations have shown continuous recruitment over
100 years, including rapid recruitment in populations killed by fire and isolated from a seed
source by several kilometres (Webster and Johnson 2000). Review of current and historical data
7
indicates that white pine blister rust is moving northward (Bourchier 1952; Kendall et al. 1996),
and will inevitably increase the rate of mortality in the northern portion of the Alberta range.
Figure 1. Known range of limber pine in Alberta.
8
2.5 Ecological Role
Limber pine is a pioneer species capable of quickly establishing on exposed sites, including
those resulting from fires — a result of its life strategy adaptations (Steele 1990). Old stands of
limber pine are often found on more exposed sites that are not favourable to other species of
trees. Once established, limber pine modifies the environment by providing wind barriers and
ameliorating soil conditions, thereby aiding the establishment of other tree species and
herbaceous plants (Baumeister and Callaway 2006).
Seeds from limber pine are a food source for red squirrels, other rodent species, black bears
(Ursus americanus), grizzly bears (Ursus arctos) (McCutchen 1996), and Clark’s nutcrackers;
some of these animals also contribute to seed dispersal (Tomback et al. 2005). Reports of black
and grizzly bears feeding on seed caches are rare, although the presence of limber pine seeds in
bear scat has been confirmed in at least two locations in Alberta (Waterton Lakes and the
Porcupine Hills; United States Department of the Interior and United States Geological Survey
2012).
Limber pine is a keystone (foundation) species, and changes to populations will have impacts on
the other species that depend on it to any extent, such as Clark’s nutcracker, and grizzly and
black bears.
2.6 Clark’s Nutcracker Biology
Clark’s nutcracker is a jay-sized corvid that resembles a crow in form and flight pattern. This
bird is found in montane and subalpine forests in western Canada and the United States. The
Canadian range of this species extends from the eastern slopes of the Coast Ranges through the
southern and central interior of British Columbia and into the Rocky Mountains of southwestern
Alberta (Salt and Wilk 1966; American Ornithologists’ Union 1983; Campbell et al. 1997).
Particularly large numbers of this bird occur in Banff National Park (Taverner 1949; Semenchuk
1992). Most knowledge concerning the species’ biology originates from work in the United
States.
Clark’s nutcracker prefers coniferous forests that are dominated by large-seeded pines (such as
whitebark pine and, to a slightly lesser degree, limber pine). The seeds of these trees constitute
the majority of the bird’s specialized diet year-round. The species has a unique sublingual pouch
(a pouch under the tongue) to transport seeds to cache sites, and a long, sharp bill to open conifer
cones, extract seeds, and place seeds in caches. In addition, this species has a remarkable spatial
memory, which enables the relocation of thousands of seed caches within a year of storage.
Nutcrackers typically cache seeds within a few hundred metres of the source tree, but can also
travel 30 km or more, typically downslope, to distant cache sites (Tomback 1978; Hutchins and
Lanner 1982; Lorenz and Sullivan 2009; Lorenz et al. 2011). The bird depends on these seed
caches for much of its food supply throughout the year, even utilizing them to feed nestlings and
juveniles.
9
Data on changes in habitat availability for Clark’s nutcracker are lacking, but the existing threats
to limber pine and whitebark pine (white pine blister rust, mountain pine beetle, competition,
etc.) may have had a significant negative impact on overall nutcracker distribution (Tomback
1998). In the long term, the continued decline of whitebark and limber pine will likely result in
overall reduction in habitat availability for the nutcracker. There is evidence from research in
Montana that once cone production and live basal area fail to reach a certain threshold, a vast
reduction in whitebark pine seed dispersal will result (McKinney and Tomback 2007; McKinney
et al. 2009; Barringer et al. 2012). Recent research conducted in Glacier National Park and in
Waterton Lakes National Park in comparison with the Greater Yellowstone Ecosystem has
demonstrated that in areas of highest white pine blister rust infection: 1) whitebark pine cone
production is lowest (Barringer and Tomback 2009); 2) there are fewer nutcrackers (Barringer et
al. 2012; McKinney and Tomback 2007; McKinney et al. 2009); and 3) there is insufficient live
basal area of whitebark pine to support seed dispersal by nutcrackers (Barringer et al. 2012;
Wong 2012).
There is no known trend in nutcracker population numbers in Alberta (Federation of Alberta
Naturalists 2007), but populations are known to fluctuate from year to year in response to food
availability. Nutcrackers preferentially harvest and cache the large, wingless seeds from
whitebark and limber pine, which ripen in late August and early September, but can also use
Douglas-fir seeds (Tomback 1998). Seed caches are essential to carry the birds through winter
and spring and to feed the young. If cone crops fail, Clark’s nutcrackers will wander in search of
food starting in late summer. Local populations may decline and have fewer offspring as a result
of poor seed production (Bradbury 1917; Mewaldt 1948). Populations appear to recover rapidly
from regional declines caused by soft pine cone crop failures (S. B. Vander Wall pers. comm.,
cited in Tomback 1998). However, widespread cone crop failure will result in long-distance
irruptions (birds travelling long distances away from the local area to new areas in search of
food) and likely high mortality of birds in poor condition (Vander Wall et al. 1981).
Clark’s nutcracker is currently designated as Sensitive in Alberta (Alberta Environment and
Sustainable Resource Development 2013) and is protected provincially as a Non-game Animal.
It is not listed with special conservation status anywhere else in its range and is not federally
listed. A habitat suitability model was developed for Clark’s nutcracker during the Southern
Headwaters at Risk Project, because of concern over the decline of whitebark and limber pine
trees within the study area (Blouin 2004). The outcome of the model was a map showing
potential spring to fall habitat (four categories from least suitable to highly suitable) for the
Clark’s nutcracker in the study area. It was developed at the landscape scale using coarse
variables, and was based on published and unpublished literature and expert opinion.
Declines in whitebark and limber pine populations in Alberta and other areas of the northern
Rocky Mountains may lead to declines in nutcracker numbers, and possible shifts in distribution.
An increased frequency of irruptions in search of food may also occur. Although the bird is able
to use other tree resources, a decline in carrying capacity as well as seed dispersal services is
likely (Tomback and Kendall 2001). Conservation of whitebark and limber pine in Alberta is
important to protect this bird species from decline.
10
3.0 THREATS AND LIMITING FACTORS
3.1 Overview
Two main threats have been established as affecting the survival of limber pine: white pine
blister rust (an introduced species) and increased mountain pine beetle activity (Means 2011).
Several other factors affect limber pine health, most notably fire effects, climate change, other
insects and disease, and cattle grazing (Means 2011), but the severity of these threats varies by
region and they require further research. Individually, the threats have detrimental effects on
limber pine, but one or all may be acting upon the same stand at the same time to significantly
exacerbate decline. There is some evidence that limber pines stressed by rust infection are more
susceptible to attack by mountain pine beetle (Kegley 2006). The threats are summarized and
described below in the context of Alberta limber pine stands (Table 1).
Limber pine populations that are experiencing dramatic declines, as a consequence of the threats
that are outlined below, have a high potential for loss of genetic diversity and, therefore, an
impaired potential for evolutionary resilience as populations reach low levels. This evolutionary
resilience is determined by the kind and amount of adaptive genetic variation occurring among
individuals within populations of a species as well as the genetic variation occurring among
populations of the species. There are several ways in which significant mortality can affect the
genetic capacity of populations to recover. The first is the reduction of total genetic variation
(i.e., a genetic bottleneck), and the second is the loss of genes as a result of increased genetic
drift, which occurs in increasingly small mating populations. These processes, which result in
loss of genetic variation, present a challenge for species recovery.
3.2 Threat Assessment
The recovery team undertook an assessment of the threats to limber pine based on published
information and expert knowledge. The team determined the relative significance of each threat
to the recovery and conservation of the species by evaluating the degree to which the threat is
affecting or will affect limber pine and identifying the probability of occurrence and severity for
each threat (Table 1).
Table 1. Limber pine threat assessment.
Threat
White Pine Blister
Rust Infection
Mountain Pine Beetle
Infestation
Probability
(H/M/L)
Effect
Severity
(H/M/L)
(local/rangewide)1
Mortality and reduced reproduction of limber
pine
High
High - range
Potential loss of genetic diversity
High
Medium - range
Mortality
Low
High - range
Potential loss of genetic diversity
Moderate
Medium - range
11
Threat
Probability
(H/M/L)
Effect
Severity
(H/M/L)
(local/rangewide)1
Unknown –
range
Unknown - range
Reduction in current habitat suitability and
availability within existing range of limber pine
Low natural limber pine establishment in areas
where new habitat becomes suitable
Unknown
Increased mortality from mountain pine beetle
Emergence of new native and exotic insects and
disease that kill or injure limber pine
High
Moderate-high
High – range
Unknown –
range
Altered fire regimes (frequency, severity, size)
Current – Low
Future – Medium
High
High - range
High
High - local
High
High - local
Potential loss of Clark’s nutcrackers at threshold
of low limber pine density resulting from death of
trees
Removal of trees by commercial, industrial, or
recreational activities
High
High - range
High
High - local
Cattle
Grazing and trampling that damages or destroys
young trees
Unknown
High - local
Habitat
Loss/Alteration
Alteration of sites, during or following
commercial or industrial activity, that inhibits the
natural regeneration of seedlings
Low
Moderate - local
Climate Change
Fire
Loss of Primary Seed
Dispersing Agent
Commercial,
Industrial and
Recreational Activity
in Limber Pine
Habitat
Loss of mature stands and regeneration potential
to fire
Increased competition in seral stands from lack of
low intensity fires
Lack of stand-replacing fires, resulting in aging
lodgepole pine forests, which increases suitable
lodgepole pine hosts for mountain pine beetle
within flight distance of limber pine stands
Unknown
High - local
1
Severity is assessed as high, medium, low or unknown, and at either the local or Alberta range-wide scale.
3.3 White Pine Blister Rust
Limber pine, whitebark pine, and other five-needle, or soft, pines are highly susceptible to the
non-native fungus disease white pine blister rust. White pine blister rust has caused high
mortality in limber pine in the United States and in the southern portion of the Alberta range, and
is thought to be moving northward in its range (Alberta Sustainable Resource Development and
Alberta Conservation Association 2007). The disease has a complex life cycle which includes
five spore stages and alternation between soft pines and Ribes (currants and gooseberries)
species as hosts. Some Pedicularis and Castilleja species are also hosts of white pine blister rust
(McDonald et al. 2006), although their role in the infection of pines is unclear.
12
3.3.1 History of invasion
This fungus species is native to Asia but had spread to Europe by the mid-1800s, likely with the
aid of humans. The fungus was first detected (on the alternate host, Ribes) in eastern North
America in 1898 (Spaulding 1922). It is believed that there were several separate introductions
within the following few years, as a result of the movement of infected seedlings of eastern white
pine, grown in Germany and France, to many locations in northeastern North America
(Spaulding 1911). By 1919, the disease had spread to Ontario and Quebec and as far west as
Minnesota. Spaulding (1922) attributed the introduction of white pine blister rust to western
North America to a shipment of eastern white pine seedlings from France to a plantation at Point
Grey, Vancouver, British Columbia in 1910. From there, the disease would have spread
throughout most of western Canada and the western U.S. Others, however, contend that there
were multiple introductions of Cronartium ribicola to the Pacific Northwest, most likely through
importations of both cultivated Ribes and white pine, and that the spread of infection occurred far
too quickly to be attributed solely to the Point Grey introduction (Hunt 2009 and references
therein; reviewed in Geils et al. 2010).
There are two distinct genetic variants of white pine blister rust in North America: an eastern
variant and a western one (Hamelin et al. 2000), representing the two major colonization events
on the continent. Alberta populations growing on limber pine have been shown to be of the
western type (Joly 2005).
The disease was first reported from Alberta (on Ribes) in 1951 (Canadian Forest Service,
unpublished data), and found a year later on limber pine near Table Mountain in the southwest
(Bourchier 1952). The first record from whitebark pine in Alberta is in the Crowsnest Pass area
in 1953 (Bourchier 1953). By 1962, limber pine stands in and around Waterton Lakes National
Park had been heavily infected (Gautreau 1963), and white pine blister rust was present on
limber pine and Ribes 144 km and 160 km, respectively, north of the international border
(Gautreau 1963). Surveys of limber pine in 2003–04 and 2009 showed that white pine blister rust
is found throughout the range of limber pine in Alberta, with damage decreasing from the south
to the north (Smith et al. 2013b). Re-assessment of these sites in 2009 showed that infection and
mortality are increasing range wide in Alberta (Smith et al. 2013b).
3.3.2 Disease cycle
The infection of limber pine by white pine blister rust is accomplished through the establishment
of basiodiospores, which are produced on Ribes in the fall following a few days of cool and
moist conditions. Basidiospores are disseminated by wind and, as they are thin-walled and
fragile, are highly vulnerable to sunlight and desiccation.
When basidiospores land on soft pines, fungal hyphae grow through the stomata of the needles
into the phloem (vascular tissue) of the branch and along the branch (McDonald and Hoff 2001;
Geils et al. 2010). Within one or more years, elongated cankers are produced within the area of
infection. In the spring, pycnia, or spermagonia, are formed in living pine tissue along the
margins of cankers, and these produce sweet droplets containing the sexual pycniospores
(spermatia). In late spring, aecia form in the tissue that produced spermagonia. Aecia are whitish
blisters that break through the bark and erupt to release orange-yellow asexual aeciospores.
Aeciospores are thick-walled and resistant to desiccation, so they are capable of being dispersed
13
by wind hundreds of kilometres in a single year (Mielke 1943; Geils et al. 2010). Aeciospores
infect only alternate hosts (not pine). Within a few weeks following infection of the undersides
of Ribes leaves, orange, dome-shaped uredinia are formed, and these produce asexual, orange
urediniospores throughout the summer during cool, wet periods. These spores re-infect the same
or nearby Ribes, or other alternate hosts, thereby spreading the disease. In August, when nights
are cooler, hair-like telia are formed, which produce teliospores. The teliospores germinate in
place on the alternate host, resulting in production of basidiospores, thereby completing the life
cycle.
3.3.3 Impacts
As white pine blister rust infects the bark and phloem of stems and branches, it creates cankers
and destroys the conductive tissue. The most obvious and serious impact of white pine blister
rust is tree mortality. Once the fungus spreads to the lower bole, tree mortality is virtually
assured. However, branch mortality is also important, as it affects cone production and
subsequent dispersal of seeds. Branch mortality, particularly within the upper third of the crown,
typically occurs before the tree itself is killed (McDonald and Hoff 2001). The earliest survey of
white pine blister rust on limber pine occurred on the east slope of Sofa Mountain (Waterton
Lakes National Park) in 1958 (Gautreau 1963). At that time, 75% of trees were infected but no
tree mortality had been noted. When the same area was surveyed in 1960, 100% of trees were
infected and low levels of tree mortality were observed. By 1962, 83% of trees had been killed
by rust, and most young trees were infected.
Health assessment plots in the province have been established since 2003 by a number of
agencies (see Table 2 and Section 3.3.3). Over all 85 plots (including two in BC), white pine
blister rust infection increased from 33% in 2003–2004 to 43% in 2009, while mortality
increased from 32% to 35%. Infection and mortality is highest in southern Alberta, and decreases
near the northern limit of the range of limber pine, but is present in all areas. Twelve transects
that have been measured three times showed varied infection levels from 73% in 1996, to 46% in
2003, to 66% in 2009. The decline in infection between the first two measurements, followed by
a sharp increase of 3%/year to 2009, could be explained by a wave of new infection between the
latter two measurements, in which some of the putatively phenotypically disease-resistant trees
at the earlier sampling period subsequently succumbed to infection when further exposed (Smith
et al. 2013b). Mortality increased from 30% in 1996, to 50% in 2003, and was 46% in 2009, for
an overall mortality rate of 1.2%/year. The fact that mortality appears to have reached a plateau
between the latter two measurements suggests that most of the trees that were susceptible to
WPBR have already died and therefore, only trees with some resistance persist (Smith et al.
2013b). This also demonstrates the importance of long-term monitoring and temporal scale in
inferring trends.
In 2005, six transects were measured in Alberta protected areas: Beauvais Lake Provincial Park,
Bob Creek Wildland Park and Plateau Mountain Ecological Reserve (listed south to north).
Infection levels were 7%, 22% and 14%, south to north. Mortality levels were 63%, 32% and
2%, south to north (K. Ainsley and A. Benner, unpublished data).
The low regeneration of limber pine in many severely infected stands means that mortality
outpaces recruitment, resulting in population decline in most stands in the southern half of the
14
range in Alberta (Smith et al. 2013b; Van den ham 2009). Clearly white pine blister rust is
having a severe impact on limber pine, and the condition is expected to worsen.
Another possible impact of white pine blister rust is a decline in the genetic diversity of limber
pine. Some Canadian populations of limber are genetically unique compared to populations in
the U.S. (Mitton et al. 2000), and this genetic diversity is important to the future conservation
and, potentially, viability of limber pine in Canada. Ongoing research (Peters and Gelderman
2011; D. Langor, unpublished data) is assessing the impact of white pine blister rust on the
genetic diversity of limber pine, as well as on seed production and quality.
It was recently discovered that white pine blister rust naturally hybridizes with the comandra
blister rust (Cronartium comandrae) — a native rust on hard pines — and that hybrids occur on
limber pine in Alberta (Joly 2005; Joly et al. 2006). This may have implications for the
pathogenicity of rusts on limber pine. Further work is needed to identify the risks associated with
hybridization of rusts.
3.4 Mountain Pine Beetle
3.4.1 Biology
The mountain pine beetle is a native bark beetle of western Canada, and can have serious
impacts on mature pine. Primary hosts in Western Canada are lodgepole pine, ponderosa pine
and western white pine, but mountain pine beetle can infest and kill any native pine including
limber pine (Safranyik and Carroll 2006). Limber pine is readily attacked by mountain pine
beetle for feeding and breeding, and is a superior host to lodgepole pine because of its thick
phloem and bark (Langor 1989; Langor et al. 1990).
Mountain pine beetles typically undergo a one-year life cycle, but may take two years to
complete development at higher elevations where they experience cooler temperatures that
protract development (Safranyik and Carroll 2006). Most of the life cycle is completed under the
bark of the host tree, but adults emerge in late summer to mate and find new hosts. Adult beetles
typically disperse within the stand, but an unknown proportion leaves the stand for long-range
dispersal (Safranyik and Carroll 2006). Trees attacked by mountain pine beetle show visible
signs, most notably exuding resin (i.e. pitch tubes) caused by the tree’s defense response to
intrusion by the beetle, and a fading crown when foliage turns from green to yellow-red to
completely red.
Mountain pine beetle uses a mass attack strategy to overwhelm a tree’s defenses, which involves
a complex interaction of beetle- and tree-produced volatile chemicals (Safranyik and Carroll
2006). Attacking beetles chew through the bark and tunnel through the phloem to mate, lay eggs
and develop to adulthood. The tree’s defenses are overcome through cooperative behaviour
among the attacking beetles and a mutualistic relationship between the beetle and several species
of ophiostomatoid (root-colonizing) blue-stained fungi (Safranyik and Carroll 2006; Rice et al.
2007). It is not exactly clear what kills the tree, but a combination of beetles tunnelling in the
phloem and fungi penetrating both the xylem and phloem, facilitates tree exhaustion from
15
defense responses and disrupts water transport within the tree (Six and Wingfield 2011),
effectively girdling the tree.
Mountain pine beetle population dynamics are dictated by the availability of susceptible hosts,
weather and climate. Beetles prefer large trees, as tree diameter is correlated with bark and
phloem thickness, which provide better protection from climate and predators and a better
quality food source respectively (Safranyik and Carroll 2006). Therefore, mountain pine beetle
outbreaks in lodgepole pine tend to develop in stands with trees 80 years of age and greater
(Shore and Safranyik 1992). A growing proportion of lodgepole pine in this age range across the
range of mountain pine beetle has resulted from fire exclusion policies over the last century. For
mountain pine beetle populations to increase to epidemic numbers, a sustained period of
favourable weather over several years enables beetles to complete reproduction and development
during the summer while experiencing low mortality during the winter (Safranyik 1978;
Safranyik and Carroll 2006). Climatic conditions over the past 30 years in western Canada have
become more favourable to mountain pine beetle, promoting the species’ expansion into higher
elevations and more northerly latitudes (Carroll et al. 2004). Favourable climate coupled with a
homogeneous, aging forest have created conditions for unprecedented outbreaks of mountain
pine beetle.
3.4.2 History of infestation
Historically, mountain pine beetle’s range extended from northern Mexico to the central interior
of British Columbia and from the Pacific coast east to the Black Hills of South Dakota
(Safranyik and Carroll 2006). Over the past two decades, mountain pine beetle has expanded
farther north in BC and east into Alberta as a result of a massive and unprecedented outbreak in
BC that has affected approximately 14 million hectares of pine forests (Safranyik et al. 2010).
During this outbreak, mountain pine beetle first expanded into Alberta in the early 2000s and
infested much of the western edge of the province along the Canadian Rockies. The infestations
extended from the United States border in the south to north of the Peace River region and east to
Slave Lake.
Currently, mountain pine beetle populations have declined in the southern part of Alberta and
attacked trees are rare. It is estimated that fewer than 1000 limber pine trees have been killed by
mountain pine beetle in Alberta during the current infestation (B.C. Jones, pers. comm.). Most
tree mortality occurred on the north and south sides of the Crowsnest Pass in southern Alberta,
with sporadic mortality in the Porcupine Hills. As part of the Government of Alberta’s mountain
pine beetle management program, any limber pine detected attacked by mountain pine beetle was
felled and burned.
Previous mountain pine beetle outbreaks occurred in Alberta in the mid-1940s and in the late
1970s/early 1980s (Miyagawa 1995). During the 1940s, mountain pine beetle outbreaks in the
mountain national parks (i.e., Banff and Kootenay) spread into the Kananaskis region, but
mortality to limber pine is unknown. The 1970s/1980s outbreak spread up the Flathead Valley
from Montana and entered Alberta in the Castle River Valley and in Waterton Lakes National
Park (Miyagawa 1995). By 1984, the beetles were infesting limber pine on the north side of the
Crowsnest Pass and into the Porcupine Hills (Alberta Forestry, Lands and Wildlife 1986). It is
estimated that up to 40 000 limber pine were removed as part of the 1980s control program
16
(Alberta Forestry, Lands and Wildlife 1986; Alberta Land and Forest Service, unpublished data),
with additional sporadic mortality likely in the small, isolated stands on the east side of the
Livingstone range.
3.4.3 Impacts
Mountain pine beetle causes direct mortality to the tree by effectively girdling the tree as
described in 3.4.1. Although lodgepole pine is the typical host in Alberta, research suggests that
limber pine may be a better host because of its thicker phloem and bark (Langor 1989; Langor et
al. 1990). The impacts of mountain pine beetle and white pine blister rust are cumulative and
compound the threat to limber pine. Trees infected and weakened by white pine blister rust may
be more susceptible to mountain pine beetle attack (Burns et al. 2008). Trees resistant to white
pine blister rust are highly valuable for limber pine conservation and restoration; however, these
can be attacked and killed by mountain pine beetle, thereby reducing conservation and
restoration options.
3.5 Climate Change
Climate change is predicted to affect the current distribution of limber pine. The optimal
elevational ranges for many conifers increased in the 20th century (Lenoir et al. 2008), likely as a
result of changing climate. The climate in Alberta is anticipated to continue changing, with
predicted increases in annual mean temperature of 3–5oC by 2050, and annual precipitation of
15% by 2080 (Barrow and Yu 2005). This temperature increase is expected to increase potential
evapotranspiration so that water stress during the growing season will likely increase combined
with decreased soil moisture levels (Rweyongeza et al. 2010). In addition, drought is predicted to
increase in frequency, intensity and duration (Sauchyn and Kulshreshtha 2008). While tolerance
to a broad range of stresses has allowed older limber pine to survive both the Little Ice Age (late
17th to 19th centuries) and recent warming (Case and MacDonald 1995), there is uncertainty over
future responses since climates will move outside the range of natural variability (Sauchyn and
Kulshreshtha 2008). Case and MacDonald (1995) found that limber pine growth was highly
correlated with total annual precipitation, but that there was reduced sensitivity to precipitation
and temperature as trees get older.
The potential biological responses to a changing climate are migration, adaptation or extirpation
(Aitken et al. 2008). Species with high fecundity, small seeds capable of long distance dispersal,
and short generation times (such as Douglas fir and Engelmann spruce) are thought to be able to
migrate relatively quickly in response to climate change, whereas species with small population
sizes, low fecundity, large seeds and long generation times (such as limber pine) will be least
able to migrate (Dullinger et al. 2004; Aitken et al. 2008).
Migration of limber pine could occur either to higher elevations or more northerly latitudes.
Upslope migration may be limited by unsuitable soil or geologically unfavourable terrain (Maher
and Germino 2006), especially on montane ridge tops —where limber pine frequently occurs in
Alberta — which may be below the future lower elevational treeline. Existing forests of spruce
or Douglas fir at higher elevations, or in more mesic sites, may also be a barrier to migration by
17
limber pine (Dullinger et al. 2004). West-central Alberta marks the current northern limit of the
range of limber pine.
If a species is unable to migrate, it must adapt in situ to warmer and probably drier conditions,
and possibly increasing stand density (Klasner and Fagre 2002; Aitken et al. 2008). There are
already cases where limber pine has been seriously affected by extreme drought events with low
precipitation and high temperatures (Millar et al. 2007). Under a changing climate, the early fall
season might be important to growth and survival as trees compensate for periods of water stress
in late summer (Letts et al. 2009), which may reflect limber pines wide physiological tolerances
(Schoettle and Rochelle 2000). Limber pine can be expected to suffer a significant adaptational
lag in its response to changing climate, as a result of its occurrence in relatively fragmented
populations with low fecundity and its delayed seed production (Aitken et al. 2008). Even other
pine species, with more favourable life history characteristics, are predicted to require 10
generations or >1 000 years to adapt to climate change (Rehfeldt et al. 1999, 2001).
It had been suggested that a dry, cold environment could inhibit the spread of white pine blister
rust (e.g., Campbell and Antos 2000), but it appears that the fungus is not limited by
environmental conditions wherever white pines and Ribes spp. cohabit (Kinloch 2003). Current
climate does not appear to be a limiting factor for white pine blister rust, as its range already
occurs well north of existing limber pine range, in whitebark pine stands (another five-needled
pine affected by rust) (Campbell and Antos 2000; Zeglen 2002; Smith et al. 2008, 2013a), and at
upper treeline (Tomback and Resler 2007). As the range of limber pine would be expected to
move northwards and higher in elevation with predicted climate change, it can therefore be
expected that it will continue to overlap with the range of white pine blister rust.
Recent climate change has increased one of the main threats to limber pine, as the recent
outbreak of mountain pine beetle was aided by warmer winter temperatures (Logan and Powell
2001; Carroll et al. 2004; Millar et al. 2007). Warmer winters reduce beetle mortality, and higher
summer temperatures increase brood development, which leads to a higher mortality of trees.
Most climate change predictions include an increase in the frequency and severity of wildfires
(de Groot et al. 2002; Flannigan et al. 2005). This could have differential impacts on survival
versus recruitment of limber pine (see discussion in section 3.6, below). While temporal and
spatial patterns of establishment vary among sites, limber pine is generally capable of
establishing quickly on disturbed and exposed sites, including those resulting from fires
(Webster and Johnson 2000; Coop and Schoettle 2009), although total regeneration may be slow
(Coop and Schoettle 2009). On more mesic forested sites, limber pine facilitates succession to
spruce and fir (Rebertus et al. 1991; Donnegan and Rebertus 1999), so if climate change forces
limber pine to move upwards it will face increased competition with these species. At lower
elevations, limber pine facilitates the expanded distribution of Douglas fir (Baumeister and
Callaway 2006). While it is generally accepted that fires create openings for Clark’s nutcrackers
to cache seeds (although see section 3.6, below), these openings also create better habitat for
Ribes spp., and thus increase the risk of blister rust infection (Coop and Schoettle 2009).
Drought-stressed trees are susceptible to further attack by limber pine dwarf mistletoe
(Arceuthobium cyanocarpum) (Millar et al. 2007). Cold temperatures often limit the range of this
18
species of mistletoe (not currently found in Canada, but in nearby Montana), so increases in
temperature likely will result in range extensions for the mistletoe both latitudinally and
elevationally (Kliejunas 2011). Severe infestations of Dothistroma needle blight (Dothistroma
septosporum) are causing mortality in limber pine in northern Montana (Jackson and Lockman
2003), and increases in precipitation may be favourable for increasing the spread and impact of
the disease (Watt et al. 2009; Kliejunas 2011). Dothistroma needle blight has reached epidemic
proportions on lodgepole pine in northwest British Columbia in the last decade, with climate
change a key factor in its spread (Woods et al. 2005; Kliejunas 2011). In addition, climate
change could potentially lead to the emergence of new native and exotic insects and diseases that
kill or injure limber pine. Although likely new species will occur in limber habitat, the severity
of the threat is as yet unknown.
Seed dispersal by nutcrackers results in limber pine often growing in small, widely-separated
populations, which can limit genetic exchange and increase the potential for local extirpation
(Schoettle 2009). Should additional fragmentation occur because of climate change, these effects
could be exacerbated. Mortality from mountain pine beetle and white pine blister rust may
reduce genetic diversity both across the population and within local populations, which would
further limit the capacity of limber pine to adapt to climate change.
Little climate modelling has been done for limber pine, but one study for British Columbia,
which contains only a small portion of the range of limber pine, suggests that all of the current
range would be unsuitable as habitat, but an area more than twice the size of the current range
would become suitable in new areas (Hamann and Wang 2006). At the continental level,
McKenney et al. (2007) modelled two scenarios at opposite ends of the spectrum; full dispersal
(species is able to migrate into its entire future habitat) or no dispersal (species is unable to
migrate; only remains in some areas within its current distribution). With full dispersal, limber
pine gained 7.8% in habitat area and moved north 6.4º, while with no dispersal it was reduced to
56% of its current area. However, this analysis overestimated the current range of limber pine,
and thus likely overestimates future range expansion. Furthermore, the models in both of these
studies are based solely on the climate envelope (i.e., temperature and precipitation) and do not
take into account biological factors such as mountain pine beetle or white pine blister rust
(Schoettle et al. 2008), or processes such as inter-species competition and fire mortality, all of
which are likely to limit limber pine’s ability to migrate to new habitats and may contribute to
extirpation of local populations.
3.6 Fire
Limber pine experiences varying fire regimes throughout its range and the effect of fire depends
on the site as described by Coop and Schoettle (2009). When open growing on rocky,
unproductive sites with little fuel, fire is rare and not important. On productive sites limber pine
may be dependent on fire to remove competition and open up sites for seed caching by
nutcrackers. Fire frequency is also important as a long fire return interval will facilitate limber
pine expansion into grasslands and increase stand density (Keane et al. 2002; Brown and
Schoettle 2008)
19
There is little information on the role of fire on limber pine populations in Alberta aside from
studies on populations in unproductive sites in the Kananaskis Valley (Webster and Johnson
2000). They showed that fire can cause either local extinction or have no effect and that
nutcrackers quickly cached seeds in burns, enabling rapid recolonization of extirpated
populations. Limber pine is a pioneer species in burned areas in the U.S., and there is
considerable mention in the literature of Clark’s nutcracker preferring to cache seeds in recently
burned areas. However, in a study of Clark’s nutcrackers caching whitebark pine seeds, Lorenz
et al. (2008) could not find research supporting the idea that nutcrackers prefer burned areas for
caching of seeds. The attractiveness of burned sites for caching of seed by Clark’s nutcracker has
not been examined in Alberta. Fire regimes in the foothills and subalpine habitats have changed
in Alberta in the past century, and less recently burned habitat is available than in the previous
century (Rhemtulla et al. 2002; Luckman and Kavanaugh 2000).
In summary, fire is a natural and important process in limber pine ecosystems that promotes
regeneration. However, under the current threat of white pine blister rust caused mortality in
mature stands, fire may be a serious threat to reproductive success. Fire exclusion policies have
facilitated competition in seral stands by preventing low intensity fires from removing new
competing growth. The lack of fire on the land has created mature lodgepole pine forests that
facilitate large scale mountain beetle infestations that can move into limber pine as observed in
the 1980s (Alberta Forestry, Lands and Wildlife 1986). Overall, the severity and probability of
fire as a threat to limber pine in Alberta is poorly understood. More studies and information is
required to make informed management decisions.
3.7 Loss of Primary Seed-dispersing Agent
Limber pine is not as dependent on Clark’s nutcrackers for seed dispersal as is whitebark pine,
but the bird is still considered an important seed dispersal agent for limber pine. As whitebark
and limber pine populations decline, there is the potential for a local loss of Clark’s nutcrackers
to occur as a threshold of low density of these tree species is reached. If this happens over a
larger area, as seems likely, Alberta coniferous forests would not be able to support large
populations of Clark’s nutcrackers, and they might disappear from large portions of their current
range. The recent research conducted on whitebark pine in Waterton Lakes National Park shows
lower cone production, few nutcrackers, and insufficient live basal area to support seed dispersal
by nutcrackers (Barringer and Tomback 2009; Barringer et al. 2012; C. Wong, pers. comm; see
also Section 2.6). This suggests that seed dispersal of limber pine could be reduced once that
threshold of food sources for Clark’s nutcrackers is reached.
3.8 Other Threats
There are a number of other potential threats to this species, which on their own are not causing
decline but, in concert with the main threats outlined above, could contribute to decline and thus
should be minimized wherever possible.
20
3.8.1 Cattle Grazing
Throughout most of its range in the Montane Natural Subregion, limber pine grows in grassland
habitats that are also subjected to cattle grazing; this is especially so in the Porcupine Hills and
further south. Grazing occurs on private land as well as public land licensed or permitted for
grazing. There are no data about the effects of grazing or trampling on limber pine regeneration,
but these potential threats require further study.
3.8.2 Habitat Loss/Alteration
Unlike most other species at risk in Alberta, habitat loss is not the main threat affecting limber
pine. However, given the ongoing declines resulting from other threats, habitat loss or alteration
may exacerbate declines and would be particularly detrimental in suitable regeneration sites
where resistance to white pine blister rust may potentially emerge. Adverse effects on habitat
may include any alteration of sites during or following commercial or industrial activity that
could inhibit natural regeneration of seedlings, as well as grazing and trampling by cattle, which
damages young trees and may alter hydrology in a way that hampers natural regeneration.
3.8.3 Incidental Removal of Trees during Commercial or Recreational Activities
The removal of individual trees during activities such as forestry, energy exploration and
extraction, mining, and recreational trail development can occur without attendant alteration of
habitat. Cattle may also damage or kill young trees while grazing. Such losses can exacerbate
local population decline and may remove trees that are resistant to white pine blister rust.
3.8.4 Seed Losses to Red Squirrels
Limber pine populations in Alberta experience significant levels of cone removal by red
squirrels, up to an average of 80% cone removal in poor cone years across a range of habitat
types (Peters and Vandervalk 2009). Cone production is highly variable between years (Peters
and Gelderman 2011), and mast years allow significant amounts of seeds (54%) to escape
squirrels, resulting in more than 10 times as many cones being available for dispersers in mast
versus non-mast years (Peters 2012). It is not known whether limber pine populations in Alberta
are seed-limited, disperser-limited, or substrate-limited.
3.9 Biologically Limiting Factors
The biology of limber pine allows it to survive in extreme habitats and under severe conditions.
However, some aspects of its biology make it more vulnerable to the threats discussed above.
Late maturation and infrequent mast years result in low fecundity. This, coupled with its slow
regeneration time and existence in fragmented populations on the landscape, which restricts gene
flow and migration opportunities, makes limber pine less resilient to high mortality events, such
as fire, insects and disease. Limber pine occupies a relatively narrow range of environmental
conditions, making it a habitat specialist. Limber pine is reliant upon the Clark’s nutcracker,
which itself is a habitat specialist, for long range seed dispersal. This suite of biological traits
makes limber pine particularly susceptible to cumulative effects from the threats described
above.
21
4.0 CRITICAL HABITAT
The identification of critical habitat is required as part of the preparation of a federal recovery
strategy for species listed as Endangered or Threatened under the federal Species at Risk Act.
Limber pine is not listed federally, although it may be in the future. If this happens, a federal
recovery strategy for limber pine will be written and critical habitat data will be collated and
analysed. There are many recovery activities either underway or identified in this plan that may
eventually contribute information to federal critical habitat identification.
5.0 RECENT RECOVERY AND CONSERVATION EFFORTS
Information on the broad geographic distribution of limber pine in the province is fairly
complete, but specific information on stand locations is more limited. In recent years, health
assessment plots (Smith et al. 2011; K. Ainsley and A. Benner, unpublished data) and aerial
surveys (J. Gould, unpublished data) have contributed location information.
Health transects have been established in the province since 2003 by several agencies. These
efforts are summarized in detail in Section 3.3.3 as part of the impact of white pine blister rust.
The anti-aggregant phermone verbenone (trimethyl-bicyclo-heptenone), and green leaf volatiles
that mimic deciduous trees (thereby preventing their detection by pine beetles), have been used
to protect phenotypically blister rust-resistant seed-producing limber pine trees — known as
“plus trees” — in Waterton Lakes National Park (Smith 2009).
Seed collecting for genetic testing and ex situ (off-site — outside a species’ natural habitat) gene
banking has been undertaken by the Alberta Tree Improvement and Seed Centre since the mid1970s (L. Barnhardt, pers. comm.), and for restoration by Parks Canada since 2010 (C. Smith,
pers. comm.). Both bulk and single tree collections have been made. Seeds from plus trees have
been entered into the US Forest Service’s blister rust screening program at the Coeur d’Alene
Nursery in Idaho (Sniezko et al. 2011). This is a 5–7 year trial to determine blister rust
resistance.
One limber pine ex situ tree gene reserve was established by the Alberta Tree Improvement and
Seed Centre in 2010 within the Panther Corners Public Land Use Zone in the Southern Rockies
of Alberta. Both single tree and bulk seed collections have been made from this stand, which as
yet does not show evidence of white pine blister rust. It is an uneven-aged stand with sparse but
healthy regeneration. This tree gene conservation reserve was established to represent a unique
subalpine population of limber pine occurring at 1 900 m. The site is now covered by a
Protective Notation from Alberta Environment and Sustainable Resource Development.
22
Three restoration planting projects have been undertaken in southwestern Alberta. One was a
grassroots effort in the Castle Special Management Area to collect seed locally, and then plant it
directly in the ground, using different treatments (seed nicked, unnicked, protected, etc.; Reg
Ernst, pers. comm.). The second project was in Waterton Lakes National Park, where a planting
experiment compared health and survival between seeds and seedlings (Smith et al. 2011). Since
then, in 2012 and 2013, Waterton Lakes National Park has planted over 1 000 seedlings for
restoration (C. Smith, pers. comm.).The third project was a community education and outreach
planting on private land near Lundbreck, where a grazing and trampling experiment compared
seedling survivorship and height growth (Vern Peters, pers. comm.)
Timber companies operating in the C5 Forest Management Unit must follow operating ground
rules that specify that limber pine cannot be destroyed or removed without written approval from
ESRD. Companies must make written application to the department, and a field inspection may
be required.
From 2007–2010, studies on the reproductive ecology of limber pine were conducted by The
King's University College. Studies examined: 1) whether cone predation and regeneration in
limber pine forests is affected by interannual variation in seed production, white pine blister rust
infestation levels, and stand composition (Peters and Vandervalk 2009; Peters 2011; Peters
2012); and 2) whether cone production in limber pine populations is affected by white pine
blister rust levels (Peters and Gelderman 2011). Eight populations have been studied in a region
with high levels of white pine blister rust infection (Crowsnest Pass, Porcupine Hills), and nine
populations in a region with low levels of infection, at the northern limits of the species’
distribution (Kootenay Plains). This research will assist recovery efforts by 1) identifying forest
stand types most subject to seed limitation, and 2) providing readily identifiable indicators of
reproductive capacity.
Table 2. Summary of current and recent conservation efforts in Alberta.
Objective of Project
Health transects
Collecting seed from
plus trees
Experimental planting
of potentially rustresistant seeds and
seedlings
Experimental planting
of seedlings for
grazing effects and
community outreach
Ectomychorrizal fungi
research
Who
Parks Canada,
Canadian Forest
Service, Alberta
Parks, ESRD
Alberta Parks
Where
US border to
Kootenay Plains,
AB, including 2 plots
in BC
Upper Bobs Creek,
Beauvais Lake
When
2003–2004 and
remeasurement in
2009
Citation(s)
Smith et al. 2013b
2005–2009
Parks Canada
Waterton Lakes
National Park
Waterton Lakes
National Park
2006–ongoing
K. Ainsley and A.
Benner, unpub.
data
Smith 2009
2009–2011
Smith et al. 2011
Vern Peters
(The King's
University College)
Lundbreck, AB,
private land
2013–ongoing
V. Peters, pers.
comm..
Cathy Cripps
(Montana State
University) and
Waterton Lakes
National Park
2009–2011
Lonergan et al.
2014
Parks Canada
23
Verbenone protection
of plus trees
Planting of seeds
Seed collecting, some
from plus trees
Remote sensing,
predictive habitat
mapping
Genetic screening for
blister rust
Climate history from
limber pine
Squirrel predation on
cone crops
Drought stress on
physiology
Prescribed fire
Parks Canada
Parks Canada
Reg Ernst
Alberta Tree
Improvement and
Seed Centre
Greg McDermid
(University of
Calgary)
USDA Forest
Service
David Sauchyn
(University of
Regina)
Vern Peters (Kings
University College)
Matthew Letts
(University of
Lethbridge)
ESRD and Parks
Canada
Waterton Lakes
National Park
Castle Special
Management Area
Throughout AB
range
2010–ongoing
Smith 2009
2007
R. Ernst, pers.
comm.
L. Barnhardt, pers.
comm.
Alberta range
2010-ongoing
G. McDermid,
pers. comm.
Waterton Lakes
National Park
Throughout AB
range
2010, 2011
Sniezko et al. 2011
unknown
Sauchyn 2010
Kootenay Plains and
Porcupine Hills
2008–ongoing
Waterton Lakes
National Park
2006–07
Peters and
Vandervalk 2009;
Peters 2011; Peters
and Gelderman
2011
Letts et al. 2009
Kootenay Plains and
Saskatchewan River
Crossing
2009
Since 1970s
D. Finn pers.
comm.
6.0 INFORMATION GAPS AND RESEARCH NEEDS
There are some important gaps in knowledge about limber pine biology, management strategies,
and threats. If unaddressed, these gaps will impede recovery efforts. These gaps can only be
filled through targeted research and information synthesis. Recovery planning needs to begin in
the meantime, but will be adapted as more information becomes available.
The following suggested research is organized based on high, moderate, and low priority, and
directly links to recovery action priorities summarized in Table 3. Research should be
encouraged by making this list available to universities and other institutions.
6.1 High Priority
6.1.1 Inventory of Limber Pine Distribution, Population Levels, and Community Types
 Complete a detailed distribution map and inventory using aerial and targeted ground
survey data; stratify by region;
 Analyze changes in populations and/or habitats through the use of photographs from
early surveys and/or old air photos;
24



Collect data to facilitate classification of limber pine community types;
Determine detailed operational criteria for designating trees and stands as “high value.”
The current working definition is that high-value trees are those that appear to be
genetically resistant to white pine blister rust and are growing in stands with high
infection rates; high-value stands are those with low infection rates, found in areas with
high rust occurrence. In addition, healthy, mature, highly productive cone-bearing trees,
either as individuals or in stands, have high value for conservation and protection;
Synthesize and assess data and information from various research initiatives (those
assessing genetic resistance and tree health, identifying critical/essential habitat, and
determining genetic variation) to identify stands that are of high priority for protection
and recovery.
6.1.2 Identification, Testing, and Propagation of Genetically Resistant Stock
 Identify potentially resistant phenotypes and screen for genetic resistance to white pine
blister rust; and
 Incorporate the potential influence of habitat features and environmental variables on
infection, transmission and resistance into experimental designs and field testing.
6.1.3 Understanding of Cone Phenology
 Examine phenology of cones to determine:
o maturation rates of cones and seeds and viability of seed throughout Alberta
range;
o scope and extent of delayed seed maturation in context of Alberta; and
o rates of germination in relation to delayed maturation.
6.1.4 Characterization of Regeneration Sites
 Characterize preferred cache sites of Clark’s nutcracker and subsequent regeneration
niches of limber pine in sites of different origin (e.g., fire, timber harvest);
 Examine the role of competition from other tree species for regeneration across an
elevational and latitudinal gradient; and
 Examine the impact of various types of disturbance (e.g., fire, timber harvest) on
regeneration and survival at the tree and stand level across an elevational gradient.
6.1.5 Identification of Current and Future Habitat for Limber Pine
 Develop and update predictive habitat models for mature and young limber pine under
existing and future climate scenarios by using current habitat parameters (e.g., soils,
climate, biological interactions).
6.1.6 Assessment of White Pine Blister Rust Incidence and Impacts on Limber Pine Survival
 Conduct health assessments every five years using gradient of health transects;
 Assess white pine blister rust incidence, impacts on limber pine survival, and rates of
change;
 Relate assessments to key climate factors; and
 Collect other relevant data needed for a population viability analysis and compare results
to populations further south.
25
6.1.7 Determination of Causes of Differing Infection Rates in Alberta Rockies
 Analyze health transect data to determine factors associated with patterns of
disease/infection and determine whether additional data collection is required; also
determine whether larger-scale factors are important.
6.2 Moderate Priority
6.2.1 Examination of Genetic Diversity
 Characterize genetic diversity and structure, including identification of unique genotypes;
 Examine underlying genetic determinants of rust resistance; and
 Examine genetic variation in adaptive traits and rust resistance.
6.2.2 Expansion of Understanding of Ecological Relationship Between Clark’s Nutcracker and
Limber Pine
 Determine impact of reduced cone/seed production on populations of Clark’s nutcracker;
 Determine effect of mast and non-mast years on population numbers of Clark’s
nutcracker; and
 Examine the importance of limber pine seeds in the diet of Clark’s nutcracker in relation
to other potential food sources.
6.2.3 Identification of Current and Future Habitat for Clark’s Nutcracker
 Determine habitat requirements of Clark’s nutcracker for feeding, seed caching and
reproduction;
 Develop and model current and future habitat availability; and
 Develop population monitoring protocols.
6.2.4 Evaluation of Impacts of Cattle Grazing/Trampling on Limber Pine Regeneration
 Assess and quantify impact(s) of grazing and trampling by cattle on regeneration.
6.2.5 Examination of Mycorrhizal Fungi Associations
 Document mycorrhizal associates of limber pine throughout Alberta range;
 Assess the effects of geography and habitat characteristics on mycorrhizal associations;
and
 Investigate the role of mycorrhizal associations in the germination of limber pine seeds
and establishment of seedlings.
6.2.6 Identification of Age of Maturity
 Determine the age of maturity (cone production) for limber pine populations in Alberta.
26
6.3 Low Priority
6.3.1 Expansion of Understanding of Alternate Hosts of White Pine Blister Rust
 Determine importance of species other than Ribes, particularly Castilleja and Pedicularis,
as alternate hosts for white pine blister rust in Alberta; and
 Determine the distribution of alternate hosts.
6.3.2 Determination of the Role of Other Agents in Decline of Limber Pine Health
 Determine whether agents other than white pine blister rust and mountain pine beetle,
such as mistletoe, also contribute to the decline of limber pine health.
6.3.3 Examination of the Non-lethal Impacts of White Pine Blister Rust
 Determine whether white pine blister rust infections that do not kill the tree affect the
number and size of cones and seeds produced, and seed viability.
6.3.4 Evaluation of the Effects of Hybridization Between White Pine Blister Rust and Comandra
Blister Rust
 Assess the relative pathogenicity of hybrids between white pine blister rust and
Comandra blister rust. This should include an examination of the impacts of these
hybrids on the alternate hosts of white pine blister rust.
6.3.5 Determination of the Importance of Seed Predators
 Examine the extent of seed predation and its effects on the reproductive potential of
limber pine.
6.3.6 Secondary Dispersal by Small Mammals

Examine the occurrence and importance of secondary dispersal by granivorous small
mammals in Alberta.
7.0 RECOVERY STRATEGY
7.1 Biological and Technical Feasibility of Recovery
Limber pines become reproductively mature as late as 50 years of age (Schoettle 2004a), and
likely will not produce sizeable cone crops until 60–80 years of age. Thus, recovery actions will
necessarily take place over a time scale of decades. While there has been no significant loss of
habitat in Alberta, habitat quality in some areas may have been impacted by cattle
grazing/trampling, which could affect regeneration. There are areas of suitable habitat in the
Porcupine Hills and the Whaleback that are sparsely populated because of removal and burning
of almost 40 000 mature trees in an attempt to control a mountain pine beetle outbreak (Alberta
Forests, Lands and Wildlife 1986). These areas might be suitable for recovery programs using
white pine blister rust-resistant stock.
27
There are small populations of limber pine in British Columbia, but they are separated from
those in Alberta by the main ranges of the Rocky Mountains. Some U.S. populations are
contiguous with those in Alberta, but along a very narrow corridor. The closest limber pine
populations in Montana have also suffered drastic declines (Kendall et al. 1996). Seed dispersal
by Clark’s nutcracker from those populations to suitable habitat in Alberta is possible, but
improbable. While Clark’s nutcracker is not the sole disperser of limber pine seed, it is the main
one. The effects of reduced populations of limber and whitebark pine on Clark’s nutcracker are
uncertain; however, logic dictates that nutcracker numbers can be expected to decrease as the
species’ most important food sources become rare (Tomback and Kendall 2001), which will
further reduce seed dispersal (Siepielski and Benkman 2007). In Montana, vastly reduced
whitebark pine seed dispersal has been observed where cone production and live basal area drop
below a certain threshold (McKinney and Tomback 2007; McKinney et al. 2009), and this could
potentially hold true for limber pine as well. Consequently, the likelihood of a rescue effect from
British Columbia or Montana by way of Clark’s nutcracker is extremely low.
Guidelines for developing restoration strategies for limber pine are available, and these provide
initial direction for land managers to plan for recovery (Schoettle 2004b; Schoettle and Sniezko
2007; Conklin et al. 2009). Techniques are not well developed for limber pine, but techniques for
whitebark pine provide useful direction on how to collect seed (Ward et al. 2006), grow
seedlings in a greenhouse (Burr et al. 2001), plant seedlings into natural stands (Scott and
MacCaughey 2006), transfer seeds (Mahalovich 2006), and deal with white pine blister rust
(Hoff et al. 2001; Burns et al. 2008).
While fire may cause local extinction of limber pine (Webster and Johnson 2000), fire may help
the species by reducing competition (Alberta Sustainable Resource Development and Alberta
Conservation Association 2007; Coop and Schoettle 2009), and by creating seed caching sites for
Clark’s nutcracker. Use of selective cutting as a surrogate for fire may provide additional options
for reduction of competition through selective removal of more shade-tolerant trees, reduce seed
predation by red squirrels, and provide caching sites for nutcrackers.
Testing of limber pine for genetic resistance to white pine blister rust is in its infancy (Sniezko et
al. 2011, Schoettle et al. 2014), but the identification of resistant genes and breeding of resistant
trees has been effective for western white pine (Pinus monticola; Hoff et al. 2001) and is well
advanced for whitebark pine (Mahalovich and Dickerson 2004). This process may take several
decades, so in the absence of completed genetic trials, the collection of seeds from (putatively)
phenotypically resistant trees (i.e., uninfected trees producing cones within stands that have
heavy infection levels) is recommended. Such opportunities exist in southwestern Alberta in
stands that have a 40–50 year history of white pine blister rust infection.
The recovery of limber pine in Alberta is biologically and technically feasible, but the recovery
time frame spans several decades. There are several shorter-term actions that can be, and need to
be, taken to begin moving toward the long-term goal.
7.2 Guiding Principles
The conservation and management of limber pine in Alberta will be guided by the following
principles:
28

Recovery team members believe that the recovery of limber pine is both desirable and
achievable, and are committed to working together to achieve this goal. All land users
and managers within the distribution of limber pine, including all affected branches of
government, will be strongly encouraged to share responsibility for and support the goal
of limber pine recovery;

The recovery team recognizes that humans engage in activities that contribute to
economic growth in some areas where limber pine occur. The team will therefore work in
a collaborative and cooperative manner with land managers, landowners, industry, and
agencies to ensure, to the extent possible, that recovery initiatives are compatible with
sustainable land use practice;

The loss of habitat and populations of limber pine is undesirable and should be
minimized;

Recovery actions for limber pine will embrace an ecosystem (holistic) approach to
management, whenever possible;

Lack of information or scientific certainty should not impede implementation of actions
believed to be necessary to achieve the goals of this recovery plan. Scientific research
regarding limber pine and its management is desirable and should be guided by the
priorities articulated in Section 7.0;

The recovery process will be guided by the concept of adaptive management, whereby
specific actions are implemented, evaluated, and improved upon, using an iterative
approach;

Land managers and other co-operators dedicated to the management of limber pine
should be recognized for their contributions towards achieving recovery goals; and

Land managers and other co-operators will not be unfairly affected by the costs
associated with recovery measures for limber pine. The intention is that no single agency
or person will be solely responsible for the direct or indirect costs associated with the
recovery measures/implementation of these plans.
7.3 Recovery Goal
The Alberta recovery goal for limber pine is to conserve existing populations and habitat, while
restoring populations across the species’ current and historical provincial range in sufficient
numbers to continue functioning in its ecological role.
As a result of uncertainty around how many individuals/populations of limber pine currently
exist, the severity of white pine blister rust infection, and the high rates of decline, it is not
presently considered appropriate to set objectives pertaining to the abundance of mature
individuals in Alberta.
29
7.4 Recovery Objectives
7.4.1 Reduce direct mortality
 By 2015, prevent mortality from sources that can be managed (e.g.,
industrial/commercial development, recreational activities), for limber pine classified as
high value (see Section 6.1.1); and
 By 2016, have collected sufficient inventory such that land managers are informed as to
how best to mitigate loss from mountain pine beetle and fire.
Successful recovery of limber pine will require that losses of trees are minimized. This will be
especially important for mature cone-producing trees and plus trees (i.e., those with apparent rust
resistance), the latter of which may be rare and may have the potential to provide the material for
propagation of white pine blister rust-resistant trees. Furthermore, minimizing mortality prevents
genetic erosion at the population level. This objective refers predominantly to mortality from
mountain pine beetle and fire but also to incidental death of limber pine trees from commercial,
industrial, and recreational activities (e.g., forestry, energy sector exploration and development,
mining, recreational trail development).
7.4.2 Develop and Introduce White Pine Blister Rust-resistant Strains
 By 2016, develop germination and stock-rearing protocols, and develop an effective
screening program for wild candidate stands, both susceptible (that contain a few minorly
affected or unaffected trees) and resistant (i.e., relatively unaffected stands within areas
of higher infection), for collection of propagation material.
The mortality rate from white pine blister rust infection is extremely high, and the disease is
spreading across the Alberta range of limber pine. The only limber pines likely to survive are
those that are resistant to white pine blister rust or escape infection. Therefore, the only way to
maintain this species on the landscape in the long term will be to engage in landscape-level
management practices that maximize the opportunity for survivorship of mature trees, and
natural regeneration; WPBR and shifting climatic conditions will select for naturally disease
resistant individuals. Native populations need to be, supplemented by the introduction of white
pine blister rust-resistant limber pine strains.
7.4.3 Conserve Genetic Diversity
 By 2016, increase seed collection and storage, develop germination and rearing protocols,
and identify suitable sites for clone banking.
Objectives relating to gene conservation and genetic diversity are important in keeping
populations viable in the face of severe declines, as this diversity is the raw material for
evolution in a changing environment. Assessment and knowledge of landscape and
environmental patterns of among-population adaptive genetic variation are crucial to the longterm stability of the species. Genetic conservation efforts for limber pine should include both in
situ and ex situ approaches but, in this case, greater emphasis should be placed on ex situ
conservation because of the identified threats and their potential impact on in situ tree gene
reserves.
30
As a first step, there needs to be a systematic seed collection effort based on the natural regions
and subregions of Alberta, and their nested seed zones. The best approach is to use the ecological
stratification in conjunction with inventory and genetic information, particularly as new
information becomes available. This integrative approach will most effectively capture existing
genetic variation.
Bulk population collections as well as single tree seed and scion collections should be made.
Single tree selections should include random population samples as well as individual parent tree
selections from trees with putative white pine blister rust and mountain pine beetle resistance.
These ex situ activities will provide genetic materials for conservation archiving, scientific
studies, and future breeding, as well as for screening, propagation and introduction of putatively
resistant restoration stock (see 7.4.2). The scope of this work is limited and should specifically
address survival, reproductive vigour, and white pine blister rust resistance.
In situ reserves should be carefully chosen to protect them as best as possible from
environmental threats, and to buffer them from potential climate change impacts. This should be
accompanied by restoration plantings into strategically targeted populations to keep population
numbers up and aid the process of natural selection and adaptation to the altered biotic and
abiotic environment. Stands and populations with a high proportion of putative or proven
resistance to white pine blister rust or mountain pine beetle should have priority for in situ
conservation effort.
Further assessment of genetic diversity, particularly adaptive genetic diversity and its structure
within individuals, among individuals within populations, and among populations, as well as
heritability is required for efficient and effective conservation and species recovery work to
occur.
7.4.4 Manage Habitat and Natural Regeneration
 By 2017, generate sufficient data to characterize regeneration sites in Alberta, by
supporting research within government and the academic community so that operational
restoration projects can be undertaken in locations most likely to be successful.
The management of limber pine habitat and sites for regeneration is vital for successful recovery.
There are several aspects to this broad objective. First, the role of fire and other disturbance in
creating potential caching sites and reducing competition from other species must be better
understood. This point includes managing the unintended consequences of excluding fire from
aging lodgepole pine forests that can be a source of mountain pine beetle. As wildfire will
continue to be excluded from the landscape and not play the role it did historically, working
closely with fire managers to find opportunities to use prescribed fire will be essential. Second,
natural regeneration should be enhanced by growing stock and planting it out, particularly stock
from parents that show putative resistance to white pine blister rust (Section 7.4.2). Finally,
natural regeneration to counter the current high mortality rate will only be successful with
healthy populations of Clark’s nutcrackers. Therefore, knowledge of nutcracker ecology must be
improved, including understanding of characteristics of sites required for seed caching.
31
7.5 Recovery Strategies
Recovery actions for limber pine are organized under the following strategic approaches, which will
be pursued concurrently over a five-year period:
7.5.1 Population Monitoring (Inventory and Assessment)
The population monitoring strategy includes activities relating to the assessment of population
size and distribution, regeneration success, and health of limber pine in Alberta. These efforts are
required in order that management can be effectively applied where and when it is most needed.
7.5.2 Protection of Limber Pine Stands and Individual Trees
The protection strategy aims to reduce the decline and death of limber pine from fire, mountain
pine beetle, cattle trampling/grazing, and mechanical removal. These efforts will help maintain
viable wild populations through the protection of cone-bearing trees.
7.5.3 Conserve Genetic Resources, Screen, Propagate and Deploy Rust-resistant Limber Pine
This strategy relates to genetic conservation, and the collection, selection, screening, testing,
breeding, and planting of growing stock. Given ongoing and precipitous declines, mainly
resulting from white pine blister rust, recovery will not be successful without implementing this
strategy.
7.5.4 Habitat and Natural Regeneration Management
The habitat and regeneration management strategy includes all activities related to monitoring
and improving habitat quality and regeneration success, both under the current climate regime
and in the context of climate change. This includes actions to preserve the role of Clark’s
nutcrackers in regeneration and other topics related to seed fate.
7.5.5 Education and Outreach
This strategy includes all activities related to educating land managers, landowners, leaseholders,
industrial and commercial stakeholders, recovery partners, and the general public about the
conservation and management of limber pine in Alberta. The focus will be on preventing the
degradation or loss of habitat, expanding awareness of the ecological importance of limber pine
and related conservation issues, ensuring that stakeholders are informed of local recovery
initiatives and their results, and gaining support and participation in management activities.
7.5.6 Research
Most recovery strategies require research to achieve success and a set of research priorities has
been developed (Section 6.0). This strategy includes all activities to communicate research needs
to those who can fill the needs, and to engage partners to pursue research questions.
7.5.7 Plan Implementation, Management and Administration
This strategy includes all activities related to the operation of the Alberta Whitebark and Limber
Pine Recovery Team, and implementation of the Alberta Limber Pine Recovery Plan 2014–2019.
A key element of this strategy is to build linkages with other provincial, national, and
international initiatives that will benefit limber pine conservation in Alberta.
32
7.5.8 Resource Acquisition
This strategy includes all activities related to securing funding and other resources needed to
support the recovery actions detailed in this plan.
7.5.9 Collaboration
This strategy includes all activities related to leveraging expertise and funding through
collaboration among various agencies and jurisdictions in Canada and the U.S. that have a
common interest in the conservation and protection of limber pine. The actions around this
objective are not explicitly listed in Section 8.0, as collaboration is an integral part of all actions.
8.0 ACTION PLAN
There are many actions needed to achieve recovery of the Alberta limber pine population and to
meet the recovery goal and objectives identified in this plan. They are categorized here by
recovery objective. Priorities and costs for each action, as well as a timetable, are detailed in
Section 9.0.
8.1 Population Monitoring
1. Map and inventory the population of limber pine within its current distribution in
Alberta;
2. Re-assess health data on established plots every 5–6 years; re-establish transects where
necessary;
3. Collect data to facilitate the classification of limber pine community types;
4. Collect data required to run a population viability analysis, and compare results to those
for populations outside of Alberta;
5. Map mountain pine beetle infestations annually in areas with limber pine;
6. Establish data collection standards and a database(s) for inventory, health transect, and
community type data; enter limber pine data into database(s). Analyze data to determine
factors associated with patterns of disease/infection;
7. Support the development of predictive habitat models for current and future habitat
throughout the range of limber pine, incorporating predicted climate change scenarios.
Support other related initiatives;
8. Synthesize and assess data and information from various research initiatives (addressing
genetic resistance and tree health, the identification of critical/essential habitat, and
33
surveys of genetic variation) to identify stands that are of high priority for protection and
recovery;
9. Establish criteria for designating stands as “high value,” and for identifying putatively
rust-resistant trees;
10. Establish pre- and post-treatment plots and protocols to monitor the response of limber
pines at select sites where fire has occurred or will be occurring, harvesting has occurred,
or competing vegetation has been or will be removed;
11. Determine whether white pine blister rust infections that do not kill the tree affect the
number and size of cones and seeds, and seed viability;
12. Analyze changes in populations and habitats through the use of photographs from early
surveys and old air photos;
13. Survey insects and diseases currently affecting live limber pine trees, and assess the
potential for significant impacts in the future, especially under climate change;
14. Monitor and report insect and disease problems in permanent sample plots and research
plots with a limber pine component;
15. Engage with existing initiatives (e.g., integrated pest management group, citizen science
initiatives) to facilitate the early detection of plant health problems; and
16. Carry out a seed zone review to determine flexibility for seed collections and deployment
based on genetic information.
8.2 Protection of Limber Pine Stands and Individual Trees
1. Once criteria for “high-value” trees and stands have been determined, these sites should
be identified and protected as in situ reserves and seed-production stands;
2. Remove individual mountain pine beetle-infested lodgepole pine trees in or near highvalue limber pine stands;
3. Use semiochemicals (e.g., verbenone) in high-value stands as appropriate to control
mountain pine beetle;
4. Communicate to fire managers the locations of high-value stands as well as the team’s
expectations as to the protection of these identified stands;
5. Exclude, or adequately protect, high-value limber pine stands in burn units;
6. Assess wildfire risk in high-value limber pine stands;
34
7. Work with fire and forest managers to identify and manage high-risk lodgepole pine
stands that could be a source of mountain pine beetle or wildfire, posing a risk to highvalue limber pine stands;
8. Make use of fire breaks, crown thinning, and fuel reduction around and /within highvalue stands to reduce risk of destruction from wildfire;
9. Coordinate conservation action strategies with land managers to ensure that protection of
limber pine is considered in land use planning at various scales (Land Use Framework,
regional plans, site plans);
10. Review provincial policies and guidelines such as operational ground rules, forest
planning standards, forest genetic resource management standards, Environmental Field
Reports, and the Gene Conservation Plan for Native Trees of Alberta (Alberta
Sustainable Resource Development 2009); provide direction on management of limber
pine where appropriate;
11. Develop guidelines (including setbacks) for proponents requesting Public Lands Act
dispositions in limber pine habitat;
12. Explore protective options such as establishment of provincial reservations or protective
notations on sites (e.g., high value) that require protection from development or
disturbance; and
13. Implement in situ reserves as per the Gene Conservation Plan for Native Trees of Alberta
(Alberta Sustainable Resource Development 2009).
8.3 Conserve Genetic Resources, Screen, Propagate and Deploy Rust-resistant Limber Pine
1. Develop comprehensive strategic breeding and introduction plan for limber pine;
2. Develop a seed zone susceptibility rating for mountain pine beetle and white pine blister
rust and prioritize seed zones for future gene resource management work;
3. Review existing seed zones and genetic information on adaptive variation in limber pine
to determine opportunities for flexibility in collection and deployment strategies;
4. Make bulk and single tree cone and scion collections representing a strategic sample of
natural populations from natural subregions and seed zones for stratification of sampling;
5. Screen for resistance to white pine blister rust in both populations and parent trees
through collection of scions and seed from wild putatively resistant parent trees and
subsequent greenhouse and/or field tests;
35
6. Propagate seedlings for ex situ conservation for white pine blister rust screening trials
based on targeted and prioritized seed zones and for establishing multi-purpose
restoration plantings including plantings of putatively white pine blister rust resistant
stock. Also includes seedling production for education and outreach activity;
7. Factor in the potential influence of habitat features and environmental variables on
resistance into experimental design and field testing;
8. Establish, maintain and evaluate provenance/family trials for limber pine, and assess
genetic diversity across the species’ range in Alberta;
9. Establish a suitable site for a clone bank composed of putatively and screened white pine
blister rust-resistant trees as well as other phenotypes and genotypes of interest;
10. Review the feasibility of establishing seed orchards;
11. Estimate the potential loss of genetic diversity due to white pine blister rust;
12. Develop a comprehensive germplasm bank for limber pine (germplasm refers to a
collection of genetic resources such as a seed collection or live trees in a nursery); and
13. Revise the provincial genetic conservation strategy for limber pine.
8.4 Habitat and Natural Regeneration Management
1. Examine the impacts of fire and industrial disturbance on regeneration and survival at the
tree and stand level across both elevational and latitudinal gradients;
2. Examine the role of competition in stand dynamics and regeneration across elevational
and latitudinal gradients;
3. Characterize the regeneration niche of limber pine by examining sites utilized by Clark’s
nutcracker and supporting regeneration in areas of different origin (e.g., fire, harvest,
climax stands);
4. Assess the use of fire and selective thinning to remove competing plant species in highvalue stands;
5. Work with fire managers to develop strategies aimed at mitigating damage from wildfire,
and identify opportunities to use prescribed fire as a conservation tool;
6. Explore the feasibility of assisted migration of limber pine in the face of climate changeinduced habitat shift and, if feasible, recommend a course of action;
36
7. Determine the effects of white pine blister rust on limber pine cone and seed production,
including stress crops and mast vs. non-mast years, and on nutcracker population
dynamics;
8. Determine the importance of alternate host species for white pine blister rust other than
Ribes, in different habitats throughout the Alberta range of limber pine;
9. Assess nutcracker habitat requirements for feeding, seed caching, and reproduction, using
mapping and modelling approaches; repeat habitat assessment every five years;
10. Monitor nutcracker populations across the range of limber pine in Alberta in mast and
non-mast years;
11. Work with local natural history clubs and citizen science groups to obtain information on
the distribution and abundance of Clark’s nutcracker in Alberta;
12. Facilitate natural regeneration and supplemental planting of limber pine to ensure a
sufficient food source for nutcrackers to maintain populations for seed dispersal;
13. Examine the effects of seed predation by both birds and rodents on limber pine
reproductive potential;
14. Develop a study of cone development and phenology, including age of tree maturity for
cone production, rates of cone and seed development, seed nutrient dynamics through
growing season, and consequences of these factors on germination;
15. Document mycorrhizal associates of limber pine in different habitats throughout its
Alberta range and explore their role in the germination of seeds and establishment of
seedlings;
16. Identify aspects of habitat alteration that interfere with regeneration of limber pine; and
17. Build limber pine restoration into reclamation plans for commercial and /industrial
operations.
8.5 Information and Outreach
1. Engage private landowners and disposition holders in the identification and stewardship
of limber pine;
2. Provide outreach to recreational users through interpretive programs, public
presentations, and printed material; and
3. Communicate to grazing managers the effects of grazing and trampling by cattle on
limber pine.
37
4. Facilitate local ownership of restoration initiatives in communities proximal to limber
pine populations through knowledge transfer of recovery actions to interested citizen
groups and non-governmental organizations.
8.6 Research
1. Communicate research priorities to research institutions; and
2. Advocate for, sponsor, and/or implement research priorities as documented in Section
6.0.
8.7 Plan Implementation, Management and Administration
1. Maintain the recovery team co-chairs as the key contacts for consultation regarding
activities that affect or may affect limber pine, as well as for ongoing communication
regarding related initiatives;
2. Maintain the role of the recovery team in providing overall coordination and
implementation of this Recovery Strategy;
3. Conduct annual recovery team meetings and provide annual reports (including
evaluation/adjustment of recovery actions and priorities based on new information); and
4. Recognize team members’ contributions toward recovery goals.
8.8 Resource Acquisition
1. Approach government, non-government, and industry partners to solicit participation in
or funding for limber pine recovery initiatives.
38
9.0 IMPLEMENTATION SCHEDULE AND COSTS
The following schedule (Table 3) provides a timeline and estimated minimum costs associated
with the implementation of activities identified by the recovery team as being important to the
conservation of limber pine in Alberta. Costs include both direct and “in-kind” — “in-kind”
refers to costs that are absorbed within the normal operating costs of government or provided by
another organization or industry The total cost over the five-year implementation period is
$2 428 000 ($1 971 000 cash; $457 000 in-kind). In general, costs are relatively similar from
year to year because most activities will occur in all years during the implementation period.
However, the budget includes modest cost increases over the life of the Plan to account for
annual inflation. Some specific costs will decrease over time, while others will increase,
particularly because of active restoration over the range in Alberta. It is anticipated that a variety
of agencies will participate in the funding and implementation of recovery activities.
Estimated costs shown are direct and essential in-kind costs to implement recovery actions. Costs
associated with team members’ expenses to attend recovery team meetings are not included in
the table, but represent valued and necessary contributions associated with the implementation of
the recovery plan. Direct costs for earlier actions were largely met through the existing budgets
of Alberta Environment and Sustainable Resource Development (Forestry Division), Alberta
Tourism, Parks and Recreation (Parks Division), and Parks Canada (Waterton Lakes National
Park).
39
Table 3. Implementation table for limber pine recovery actions including cash and in-kind contributions. Abbreviations for agencies: ESRD =
Alberta Environment and Sustainable Resource Development; TPR= Alberta Tourism, Parks and Recreation – Parks Division; PCA= Parks
Canada Agency (Waterton Lakes National Park); CFS=Canadian Forest Service. Implementation is subject to the availability of resources,
from within and from outside government.
Recovery
Plan
Section
Action
Lead
Agency1
Cost (thousands per fiscal year)2
2014/
2015
8.1
1
2
3
Population monitoring
Map and inventory range and populations
Re-assess established health plots every 5–6
years, analyze data and create maps
Collect data for community type
classification
Collect data for PVA
ESRD
TPR
ESRD
TPR
PCA
ESRD
ESRD
4
Map mountain pine beetle infestations in
limber pine annually
ESRD
PCA/CFS
Data management and analyses
TPR
PCA
ESRD
ESRD
5
6
7
8
9
Support development of predictive habitat
models
Synthesize all monitoring and related data
to identify stands for protection
Determine criteria for “high value” trees
and stands
ESRD
TPR
ESRD
TPR
5 IK
2 IK
97.5
5 IK
5 IK
30 IK
4 IK
2015/
2016
5 IK
4 IK
2016/
2017
5 IK
4 IK
2017/
2018
5 IK
4 IK
Total
2018/
2019
5 IK
4IK
Incl. in
other
work
Incl. in
annual
MPB
survey
1 IK
1 IK
5
1 IK
1 IK
2 IK
2 IK
2 IK
1 IK
40
1 IK
1 IK
1 IK
1 IK
25
25
Priority3
1 IK
1 IK
27 IK
Urgent
97.5
40 IK
Urgent
20 IK
Urgent
0
Urgent
0
Necessary
5
10 IK
Urgent
50
Urgent
4 IK
Necessary
4 IK
Urgent
Recovery
Plan
Section
10
11
12
13
14
15
16
8.2
1
Action
Establish pre- and post-treatment
monitoring plots and protocols to assess
impacts of fire and harvesting
Non-lethal effects of white pine blister rust
Analyze change through old survey or air
photos
Carry out pest survey and assessment
Record insect and disease problems in
established permanent sample plots and
research sample plots
Engage existing initiatives to facilitate early
detection of plant health problems
Carry out seed zone review to determine
flexibility for seed collections and
deployment based on genetic information
Protection of limber pine stands and
individual trees
Identify “high-value” stands that require
protection
Remove mountain pine beetle-infested pine
in/near high-value stands
Lead
Agency1
PCA
ESRD-For
TPR
PCA
ESRD
ESRD
Deploy semiochemicals in high-value
stands to deter mountain pine beetle during
2014/
2015
1 IK
2 IK
PCA
PCA
ESRD
20
TPR
ESRD
ESRD
3 IK
ESRD
5
ESRD
As
require
d as
part of
annual
MPB
progra
m
3
2
3
Cost (thousands per fiscal year)2
PCA
2015/
2016
3 IK
13 IK
2 IK
2016/
2017
Total
2017/
2018
3 IK
13 IK
2 IK
10
25
3 IK
13 IK
2 IK
20
2 IK
1 IK
20
2 IK
1 IK
20
2 IK
1 IK
3 IK
1 IK
3 IK
1 IK
1 IK
1 IK
2018/
2019
3 IK
13 IK
2 IK
74 IK
Urgent
10
25
Beneficial
Beneficial
20
2 IK
1 IK
100
8 IK
4 IK
Beneficial
1 IK
1 IK
15 IK
Beneficial
1 IK
Urgent
10
Urgent
0
Urgent
15
Urgent
1 IK
5
41
3
3
3
Priority3
3
Beneficial
Recovery
Plan
Section
Action
Lead
Agency1
Cost (thousands per fiscal year)2
2014/
2015
4
5
6
7
8
9
10
11
12
13
8.3
an infestation
Communicate to fire managers regarding
location and protection of high-value stands
Exclude/protect high-value trees in burn
units
Assess wildfire risk in high-value stands
Work with fire and forest managers to
identify and manage lodgepole pine stands
that are at high risk of mountain pine beetle
infestation and are adjacent to limber pine
stands
Protect high-value limber pine stands from
wildfire
Coordinate conservation strategies with
land managers in land use planning.
Review and comment on provincial
policy/guidelines (e.g. forest management
planning)
Develop guidelines (including setbacks) for
Public Lands Act dispositions
Explore options for long-term protection of
stands on crown land through provincial
reservation system
Implement in situ reserves as per the
provincial conservation plan.
Conserve genetic resources, screen,
propagate, breed and deploy rustresistant limber pine
ESRD
TPR
ESRD
TPR
PCA
ESRD
TPR
ESRD
1 IK
1 IK
1 IK
1
2015/
2016
2016/
2017
1 IK
1 IK
2 IK
1 IK
1 IK
2 IK
1 IK
1 IK
2 IK
1
1
2 IK
3 IK
1
2 IK
3 IK
1 IK
1
2 IK
25
1 IK
1 IK
1 IK
1 IK
ESRD
TPR
PCA
ESRD
1 IK
1 IK
1 IK
1 IK
1 IK
1 IK
1 IK
1 IK
1 IK
ESRD
TPR
1 IK
3 IK
1 IK
1 IK
1 IK
1 IK
1 IK
1 IK
ESRD
ESRD
3
15
42
1 IK
1 IK
15
15
Priority3
2018/
2019
1 IK
1 IK
2 IK
3 IK
1 IK
ESRD
2017/
2018
Total
10 IK
Urgent
5
9 IK
Urgent
15 IK
Necessary
2 IK
Necessary
25
1 IK
1 IK
1 IK
50
10 IK
Beneficial
5 IK
Necessary
1 IK
10 IK
Necessary
2 IK
Necessary
2 IK
Necessary
63
Urgent
15
Recovery
Plan
Section
Action
Lead
Agency1
Cost (thousands per fiscal year)2
2014/
2015
1
2
3
4
5
6
7
8
9
10
11
12
13
14
8.4
Develop feasibility and strategic breeding
plan
Develop silviculture and deployment plan
Develop a hazard rating to assess risk,
prioritize seed zones, conduct selection
surveys and fill inventory gaps
Assess role of seed zones and adaptive
variation in collection and deployment
strategies
Strategically make bulk and single tree cone
and scion collections
Screen for rust resistance from seed and
scion collection from putatively resistant
trees
Propagate seedlings for ex situ conservation
and restoration plantings
Examine influence of environmental
variables on rust resistance
Establish provenance/family trials and
assess genetic diversity
Establish a field clone bank for various
genotypes and phenotypes
Review the feasibility of establishing seed
orchards (if breeding program is determined
to be feasible)
Estimate potential loss of genetic diversity
due to white pine blister rust
Develop a comprehensive germplasm bank
Revise provincial genetic conservation
strategy
Habitat and natural regeneration
ESRD-For
ESRD-For
ESRD-For
5
80
ESRD- For
5
ESRD-For
PC
ESRD-For
60
2
ESRD-For
15
2015/
2016
2016/
2017
5
5
10
50
10
50
Total
2017/
2018
10
50
Priority3
2018/
2019
10
50
10
Urgent
45
280
Urgent
Necessary
5
Necessary
60
2
15
60
2
30
60
2
30
60
2
30
310
Urgent
105
Urgent
15
15
15
15
75
Urgent
20
20
20
60
Beneficial
ESRD-For
40
40
80
Necessary
ESRD-For
40
40
80
Necessary
3
3
Beneficial
5
5
10
Necessary
5
5
25
2
Urgent
Beneficial
ESRD-For
ESRD-For
ESRD-For
ESRD-For
ESRD-For
TPR
5
5
1
1
43
5
Recovery
Plan
Section
Action
Lead
Agency1
Cost (thousands per fiscal year)2
2014/
2015
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
management
Examine impact of disturbance for
regeneration and survival
Examine role of competition in stand
dynamics
Characterize regeneration niche
Assess competition removal methods
Develop strategies for working with
wildfire and prescribed fire
Explore feasibility of assisted migration
Determine effects of white pine blister rust
on cone and seed production
Determine importance of alternate host
species for white pine blister rust
Assess nutcracker habitat requirements
Monitor nutcracker populations in mast and
non-mast years
Gather information on distribution and
abundance of nutcrackers
Ensure regeneration as future food source to
keep nutcrackers on landscape
Examine effect of seed predation on
reproductive potential
Develop study of cone development and
phenology
Document mycorrhizal associates and
examine their ecology
Identify aspects of habitat alteration that
ESRD/TPR
2015/
2016
50
ESRD
TPR
ESRD
ESRD
TPR
PCA
TPR
ESRD
ESRD
2016/
2017
2 IK
2 IK
3 IK
10
5 IK
2 IK
2 IK
2 IK
3 IK
10
5 IK
2 IK
2 IK
2 IK
2 IK
5
10
ESRD
Priority3
2018/
2019
50
50
10 IK
1 IK
2017/
2018
Total
100
Necessary
100
Necessary
16 IK
20
13 IK
18 IK
Urgent
Necessary
Beneficial
10
5
4 IK
20
15
15
Beneficial
50
1 IK
1 IK
2 IK
2 IK
Necessary
Beneficial
ESRD
TPR
PC
TPR
1 IK
2
1 IK
2 IK
2
2 IK
15
2 IK
2
2 IK
10
1 IK
2
1 IK
10
1 IK
2
1 IK
35
10
7 IK
7 IK
Beneficial
Necessary
PC
1 IK
1 IK
1 IK
1 IK
1 IK
5 IK
Necessary
20
20
20
60
Beneficial
40
2 IK
30
Necessary
2 IK
Necessary
ESRD
ESRD
2 IK
20
20
ESRD
10
10
10
ESRD
1 IK
1 IK
44
Necessary
Necessary
Recovery
Plan
Section
Action
Lead
Agency1
Cost (thousands per fiscal year)2
2014/
2015
17
8.5
1
2
3
4
8.6
1
2
8.7
1
2
3
4
8.8
1
interfere with regeneration
Build restoration into reclamation plans for
commercial operations.
Information and outreach
Engage private landowners and disposition
holders
Provide outreach to recreational users
Engage grazing managers
Community based restoration initiatives
Research
Communicate research priorities to research
institutions
Advocate for and/or sponsor research
priorities as documented in Section 6.0
Plan implementation, management and
administration
Maintain the recovery team co-chairs as the
key contacts for consultation and liaison
Conduct annual recovery team meetings and
reporting
Maintain the role of the recovery team in
providing overall coordination and
implementation
Recognize team members’ contributions
toward recovery goals
Resource acquisition
Funding securement
2015/
2016
2016/
2017
Total
2017/
2018
PCA
ESRD
2 IK
1 IK
1 IK
ESRD
1 IK
1 IK
1 IK
1 IK
ESRD/TPR/
PCA
ESRD
ESRD
1 IK
1 IK
1 IK
3
1K
3
TPR
PC
TPR
PC
ESRD
5 IK
3 IK
1 IK
1 IK
1 IK
ESRD
Priority3
2018/
2019
4 IK
Beneficial
1 IK
5 IK
Necessary
1 IK
1 IK
5 IK
Necessary
1 IK
3
3
3
2 IK
15
Necessary
Beneficial
1 IK
2 IK
1 IK
1 IK
1 IK
1 IK
2 IK
1 IK
1 IK
1 IK
1 IK
2 IK
1 IK
1 IK
1 IK
1 IK
2 IK
1 IK
1 IK
1 IK
20 IK
Necessary
15 IK
Beneficial
5 IK
5 IK
5 IK
5 IK
5 IK
25 IK
Urgent
ESRD
1 IK
1 IK
1 IK
1 IK
1 IK
5 IK
Urgent
ESRD/TPR/
PCA/CFS
5 IK
5 IK
5 IK
5 IK
5 IK
25 IK
Necessary
ESRD
0.5
0.5
Beneficial
ESRD
1 IK
5 IK
Urgent
45
1 IK
1 IK
1 IK
1 IK
Recovery
Plan
Section
Action
TOTAL
Lead
Agency1
Cost (thousands per fiscal year)2
2014/
2015
312
118 IK
1
2015/
2016
278
99 IK
2016/
2017
496
95 IK
2017/
2018
506
77 IK
Total
2018/
2019
379
68 IK
Priority3
1 971
457 IK
Lead agencies are identified for those groups that will be taking the management actions. The lead agency will engage other agencies according to all current policies,
agreements, MOUs, and availabilities of expertise. Agencies and proposed costs are in no particular order.
2
IK = In-kind contribution by identified agency(s)
3
Prioritization: Urgent = high priority for immediate species conservation, initiate as soon as possible; Necessary = medium priority for long term species conservation; Beneficial
= lower priority, primarily directed at potential future activities
46
10.0 SOCIO-ECONOMIC CONSIDERATIONS
The principles identified in Section 7.2 of this plan will guide recovery actions for limber pine.
During implementation of this recovery plan, social and economic impacts will be taken into
account as part of a cooperative approach among stakeholders. Recovery efforts will likely have
nominal economic effects on industries working in limber pine habitat, most notably forestry and
energy. The effect on these activities is small because so far, only a relatively small part of
limber pine habitat overlaps with areas suitable for industrial development (although this could
change in the future). Conversely, a large portion of limber pine’s distribution occurs on lands
with cattle grazing; however, recovery actions may only incur minor effects on
landowners/lessees who graze cattle where limber pines grow. Limber pine provides important
wind protection and refuge for cattle in the winter
Protection of high-value stands could increase the costs of industrial or recreational development
and cattle grazing. Costs to industry may occur at the planning level if it is necessary to re-align
planned roads or change block or lease boundaries. Incurrence of some cost to industry and
recreational developers would also be expected as they work to reduce their impact on
regeneration or reduce incidental death of limber pine trees; however, increased recognition and
support is anticipated for those operators that demonstrate responsible conservation practices by
accepting constraints that benefit the needs of limber pine. Costs to cattle ranchers may occur if
white pine blister rust-resistant trees are identified on grazing lands, in which case one-on-one
communications with landowners/lessees and development of stewardship approaches could be
used to mitigate most of the negative effects on individual limber pines and their habitat.
Removal of lodgepole pine trees to protect limber pine stands from mountain pine beetle risk, or
to reduce competition, could affect the timber resources in localized areas. However, monitoring
of new diseases and pests as part of limber pine recovery could benefit forestry and natural
capital.
Reducing wildfire or altering prescribed fire plans near high-value limber pine stands could
interfere with benefits that occur in the wake of fire, but could also potentially benefit other
species that prefer older-growth forest. Removal of herbaceous species to reduce competition
with limber pine seedlings could be an issue if any sensitive species are removed.
Little is known about the traditional use of limber pine by First Nations in Alberta. However, the
seeds share the characteristics of large size and significant energy content that have led to the
frequent use of whitebark pine seeds as a food source by humans in parts of that species’ range
(reviewed by Keane et al. 2012). There is speculation that the Knunaxa of British Columbia ate
and traded limber pine seeds, and further speculation that that they might have propagated them
in new areas such as along traditional trade routes, where relatively dense populations of limber
pine can be found today (R. Moody, pers. comm). Based on recent oral history interviews with
elders of the Blackfoot Confederacy (Augare-Estey 2011), whitebark pine sap and needles were
used in many ways, and it is likely that limber pine was used in similar ways. While some elders
voiced concern over human intervention in whitebark pine restoration, there seemed to be some
consensus that if done properly it would be beneficial (Augare-Estey 2011).
47
In the United States, there are several reports of First Nations use of limber pine seeds.
Prehistoric grinding stones found in Nevada were likely used on limber pine seeds (Lanner
1996). The Apache, Chiricahua and Mescalero were reported to roast and hull the seeds or
sometimes to grind and eat the seeds, shell and all (Castetter and Opler 1936).The Navajo used
the tree for medicinal or ceremonial purposes, including as a ceremonial emetic and as a
medicine for cough and fever (Vestal 1952). The Navajo were also reported to burn the seeds
(Kershaw et al. 1998) or smoke the plant (Vestal 1952); in both cases the smoke was considered
to bring good luck.
Aside from the specific conservation benefits of the species itself, and the conservation benefits
to Clark’s nutcrackers and to biodiversity when enough limber pine persists on the landscape to
maintain populations of Clark’s nutcrackers, the recovery of limber pine will benefit biodiversity
in Alberta and support the ecosystem services that this species provides.
Other activities — such as inventory, monitoring, research aimed at limber pine and Clark’s
nutcrackers, collecting cones, breeding/screening/planting, and deploying semiochemicals —
would have minimal effect on other interests or other species beyond the cost of these activities.
48
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Personal Communications
Peter Achuff, Scientist Emeritus, Parks Canada Agency (retired).
Leonard Barnhardt. Manager, Alberta Tree Improvement and Seed Center, Alberta Environment
and Sustainable Resource Development.
Reg Ernst. Independent Ecologist.
Brad C. Jones. Forest Health Officer, Alberta Environment and Sustainable Resource
Development.
Dave Finn. Provincial Fire Behaviour Specialist, Alberta Environment and Sustainable Resource
Development.
Greg McDermid, Associate Professor, Department of Geography, University of Calgary
Randy Moody, Keefer Ecological Services Ltd.
Vernon Peters, Associate Professor of Ecology, The King's University College.
Cyndi Smith. Vegetation Specialist, Waterton Lakes National Park, Parks Canada Agency
(retired).
Carmen Wong. Ecologist Team Leader, Yukon Field Unit, Parks Canada Agency.
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