Download Forests - Bruce Peninsula Biosphere Association

Forests
Definition
This feature represents all forest types including native deciduous, coniferous and mixed forests, and cultural
forests such as plantations, woodlots and windbreaks.
Ecosystem Description
The Bruce Peninsula represents the largest remaining forested area in southern Ontario, consisting of a “megawoodland” extending for 57 km from Tobermory along the Niagara Escarpment from Whippoorwill Bay near Lion’s
Head and extending to the coast to Pike Bay. The extensive natural forest cover of Bruce Peninsula is a critical
refuge for rare plants, amphibians, migratory and breeding birds, large mammals and several other wildlife
species. According to the Southern Ontario Land Resource Information System (SOLRIS), the plan area contains
66146.7 ha of forest cover, representing 69.15% of the total area. The current forest cover in the plan area is
classified as 45.94% coniferous forest, 14.35% deciduous forest, and 8.19% mixed forest with the remainder being
plantations, hedgerows, or not classified (SOLRIS 2008).
The structure and composition of the Bruce Peninsula’s forests have changed significantly since European
settlement in the mid-1800s as a result of extensive logging, agricultural settlement and human-induced fire.
Based on surveyors’ notes of the former Lindsay and St. Edmunds Townships, Suffling et al. (1995) described
changes in vegetation types from 1855-1981. The pre-settlement climax hemlock forests that dominated the
region have been largely replaced by a second-growth forest dominated by early successional species such as
eastern white cedar, trembling aspen and white birch. Stands of white, red and jack pine are still relatively
common and are often mixed with eastern white cedar. On sites with deeper soils, the natural maple-beech-oak
deciduous forest has mostly been cleared for agriculture and only pockets of this mature forest type remain on the
Bruce Peninsula. The vast majority of the present forest stands date from the early 1900s following the major fires
and logging, or from the 1920s onward as second-growth following farm abandonment in many areas. As a result
the forests on the Bruce Peninsula are primarily intermediate in age (<100 years) and much of the mature or oldgrowth forests are no longer found in the plan area. In some areas, such as Cabot Head and Hope Bay, some forest
stands are approaching an older growth, undisturbed condition (NEC 2011). Mature forests are often associated
with higher biodiversity providing multiple age-class structures and an abundance of specialized habitat features
such as tree cavities, snags and downed woody debris (Larsen et al. 1999).
Biodiversity
A wide variety of plant species specialize in forest habitat such as certain bryophytes (E.G. mosses and liverworts),
herbaceous understory plants, shrubs and of course some 40 species of trees. Within maple-beech-oak forests
there are a wide variety of herbaceous understory species including: hepaticas, trilliums, trout lily, dog-tooth
violet, Dutchman’s breeches, Indian cucumber root, Jack in the pulpit, wild leeks, blue cohosh, and wild ginger.
There are also a number of fern species that specialize in hardwood forests including maidenhair fern, ostrich fern
and the Hart’s-tongue fern, a species at risk. Jack pine, spruce and cedar forests host a different understory
assemblage, with small herbaceous plants including fringed polygala, starflower, large-leaved aster, and orchids
such as ram’s head and calypso. The dwarf lake iris, another species at risk, is also found within cedar and jack pine
forest edges. Many of these herbaceous plants as well as understory shrubs are important food sources for
wildlife, including everything from small pollinators to white-tailed deer.
CHAPTER 3: BIODIVERSITY FEATURES
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Figure 3.1. Forest community types of the Bruce Peninsula.
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COMMUNITY CONSERAVTION AND STEWARDSHIP PLAN
Figure 3.2. Dominant forest species on the Bruce Peninsula.
CHAPTER 3: BIODIVERSITY FEATURES
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Table 3.1. Total forest cover and forest type by subwatershed (SOLRIS 2008).
Watershed
2FA-02
2FA-03
2FA-04
2FA-05
2FA-06
2FA-07
2FA-08
2FA-12
2FA-13
2FA-14
TOTAL
Total
Forest
Cover (ha)
4656.58
4391.57
6222.47
7389.59
17087.94
6868.26
8953.90
9000.99
1187.64
441.43
66200.36
Forest Type (%)
% of
Watershed
Deciduous
Coniferous
Mixed
71.57
47.30
75.01
79.36
80.77
72.25
56.90
65.23
86.31
61.67
69.18
42.8
27.9
15.1
4.2
8.0
8.5
14.7
13.7
0.9
0.0
14.35
19.4
13.0
43.4
66.0
66.4
55.6
34.9
40.9
63.7
56.9
45.94
8.4
6.1
15.2
8.0
6.0
7.6
6.8
10.0
18.8
1.6
8.19
The large, relatively intact forests of the Bruce Peninsula are able to support a diverse array of flora and fauna. The
Bruce Peninsula supports an important population of interior forest birds, primarily due to the large forest size and
the location of the Bruce Peninsula within the core of the breeding ranges of many neotropical migrants. Forest
interior breeding birds are those species that need relatively large contiguous tracts of forest to support viable
breeding populations, as ovenbird, winter wren, Swainson's thrush, black and white warbler and pileated
woodpecker. The large tracts of contiguous forests on the Bruce Peninsula also provide important habitat for many
migratory land birds during spring and fall migrations. The northeastern portion of the Bruce Peninsula at Cabot
Head is recognized as an Important Bird Area (Bird Studies Canada 2005) and has a high concentration of migratory
land birds with 224 different species documented by the Bruce Peninsula Bird Observatory. Forests within a few
kilometres of the shoreline are particularly important as resting and feeding areas for species during migration.
During spring, many amphibian species concentrate in breeding pools within or adjacent to forest patches, such as
the eastern newt, blue-spotted salamander, spotted salamander, American toad, gray tree frog, spring peeper,
wood frog, leopard frog, and green frog. These breeding ponds may be along the edge of swamps, in floodplains, in
groundwater seeps, or in depressions in upland forests. Surrounding woodland habitat of various compositions
must provide a closed canopy offering a shaded, moist understory to retain breeding pond function. The forest
understorey should offer an abundance of downed woody debris to act as cover for amphibians while they are
living in terrestrial habitats. For a woodland pond to continue functioning as a breeding pond for amphibians it
must remain connected to surrounding woodland habitat to facilitate movement between the pond and
surrounding terrestrial habitats. Both elements are required by most amphibians to complete their life cycles.
The presence of large, wide-ranging mammals, such as black bears and fishers, is an indication of high ecological
integrity on the Bruce Peninsula, as these mammals are particularly vulnerable to habitat fragmentation because
of their large spatial requirements. The Bruce Peninsula is home to the southernmost population of black bear in
Ontario, which is genetically distinct due to isolation from other populations in the province. Obbard et al (2013)
estimated that 316 black bears (SE 46.6, 95% confidence interval 225–408) inhabit the Bruce Peninsula and there is
concern that the population may become extirpated within the next 50 years due to its small size and isolation,
combined with the loss and fragmentation of its habitat. Although black bears use a variety of habitats, dense
mixed and dense deciduous forests are the preferred habitat type on the Bruce Peninsula (Coady 2005). These
dense and relatively mature forest stands are important for feeding (Obbard et al. 2012), especially those that
produce hard mast items (e.g. beech nuts, acorns), and to facilitate extensive seasonal movements which can be
up to 40-80km.
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COMMUNITY CONSERAVTION AND STEWARDSHIP PLAN
Ecosystem Processes
Natural disturbance is an essential process in forest ecosystems. Forests are in constant flux when viewed from a
landscape perspective, disturbed by either catastrophic stand-replacing events such as fire, insect outbreak, and
extensive wind throw, or periodic small-scale gap processes. The frequency, intensity and scale of disturbance
events create a diverse, heterogeneous forest landscape. Forest types are often associated with a specific
disturbance regime. In some areas on the Bruce Peninsula, stands of white, red and jack pine, and red oak show
evidence that they historically required low intensity fires for continued existence (Suffling et. al, 1995). In
comparison, the maple-beech deciduous forests that dominated the southern portion of the peninsula was
primarily a wind forest and was driven by a gap dynamic process. However, humans have altered natural
disturbance regimes since early settlement on the Bruce Peninsula. It has been hypothesized that the fire regime
changed following a series of human-induced fires, which changed the vegetation landscape of the Bruce Peninsula
drastically. Furthermore, current fire prevention measures have significantly reduced the potential for large fire to
occur, which may have may have an effect on species like red oak and jack pine.
Forest Assessment
Size
Indicator: Percent of Interior Forest per Subwatershed
Current Status: UNRANKED
Description: Forest interior is the area of a forest patch that is more than 100 m from the forest edge and are
critical for many area-sensitive species. The 100 metre perimeter is considered ‘edge’ habitat and is prone to high
predation, sun and wind damage, and intrusions by non-native species. The structure and functions of habitat
edges are inherently different from those within habitat cores, and as a result, these areas tend to support a
different number and range of species (Ewers and Didham 2006). According to Environment Canada (2013), the
proportion of the watershed that is forest cover and 100 metres or further from the forest edge should be greater
than 10%.
Landscape Context
KEA: Ecosystem Connectivity
Indicator: Landscape Corridors
Current Status: UNRANKED
Description: Guidelines from Environment Canada (2013) suggest that connectivity width will vary depending on
the objectives of the project and the attributes of the forest nodes that will be connected. Corridors designed to
facilitate species movement should be a minimum of 50 to 100 metres in width. Corridors designed to
accommodate breeding habitat for specialist species need to meet the habitat requirements of those target
species and account for the effects of the intervening lands. Although it has not been used for this report, tools are
available for measuring landscape fragmentation for specific species which have been used to assess connectivity
in Bruce Peninsula National Park.
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While parts of the Bruce Peninsula forests are fragmented by roads, residential development and agriculture, the
landscape can still be considered largely intact. The Greenway Initiative (REF) identified six key connection routes
in the plan area that may provide safe movement corridors for many species and provide a basis to qualitatively
assess landscape connectivity. Although most of the routes appear to be in good condition, the connectivity is
limited along the western coast of the Bruce Peninsula at Little Pike Bay by agricultural lands and along the eastern
coast at Isthmus Bay, although this was not identified as a connection route.
Condition
KEA: Tree Health
Indicator: Crown vigour (% dieback)
Current Status: VERY GOOD
Description: Tree mortality is a natural process and allows forests to progress along expected successional
trajectories. Tree mortality is caused by a variety of natural stressors (i.e. extreme weather events, insects, and
diseases) and human stressors (i.e. fragmentation, timber harvest). Changes in tree mortality rates can alter forest
structure, composition, and ecosystem services through both species change and changes in gap dynamics
(Mantgem et al. 2009). Increased tree mortality can also have an effect on the amount and type of detritus being
deposited on the forest floor (Busing 2005). This indicator is based on the forest biodiversity monitoring protocol
developed by the Ecological Monitoring and Assessment Network (EMAN 2004) to monitor crown condition or the
percent of foliage indicating signs of dieback in dominant and co-dominant trees. Sajan (2006) proposes that a
forest stand should be considered healthy if the annual mortality rate is found to be less than 5% in dominant and
co-dominant trees. Eight forest stands monitored by Parks Canada and two by the Niagara Escarpment
Commission were considered healthy with less than 5% severe crown dieback in dominant and co-dominant trees.
The Bruce Peninsula Biosphere Association has also collected several years of data for this indicator at seven
monitoring plots but these data have not been analyzed. An additional indicator for tree health is the mean annual
mortality rate, however, there was insufficient data for this report.
Indicator: Downed Woody Debris
Current Status: UNRANKED
Description: Downed woody debris is an important structural component of forest ecosystems as it reduces soil
erosion, increases water retention, provides a seedbed for trees, influences nutrient cycling, and creates habitat
for wildlife. Downed woody debris has been assessed by Parks Canada at eight monitoring plots since 2002 based
on position, diameter and decomposition class of fallen logs and stumps. The total amount of downed woody
debris in 2008 was 1.00 m2 which was greater than the threshold of 0.87 m2 indicating a healthy condition but
insufficient data was available to assess this indicator for this report. The Bruce Peninsula Biosphere Association
has also collected several years of data for this indicator at seven monitoring plots but this data has not been
analyzed.
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COMMUNITY CONSERAVTION AND STEWARDSHIP PLAN
Map 3.3. Interior forests on the Bruce Peninsula.
CHAPTER 3: BIODIVERSITY FEATURES
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Map 3.4. Priority Stewardship Areas and Possible Connection Routes as determined by the GreyBruce Greenway Initiative.
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COMMUNITY CONSERAVTION AND STEWARDSHIP PLAN
KEA: Species abundance and composition
Indicator: Abundance of Forest Birds
Current Status: GOOD
Description: Forest birds are a diverse group of species that exhibit a wide variety of habitat requirements and
behavioural characteristics and are, therefore, good indicators of forest ecosystem integrity providing information
on a variety of ecosystem components and processes. A forest bird monitoring program has been implemented at
Bruce Peninsula National Park since 1994 using methods developed by the Canadian Wildlife Service. These
methods consist of audio surveys conducted at a sugar maple dominated forest near Emmett Lake and a cedarpine forest on Dorcas Bay, representing both deciduous forests and coastal coniferous forests. Focal species
represent four separate foraging guilds including aerial, canopy foliage, understory foliage, and forest floor
foragers. With eleven years of data a baseline was established to assess the natural variability of populations of the
focal species and to define thresholds for rating the status of each focal species in a given year. Based on data from
2006, the ecological integrity of these forest ecosystems was rated as Good or Very Good. The forest bird
community is healthy, with 7 of 9 targeted species within or above expected values.
Indicator: Abundance of Eastern Red-backed Salamanders
Current Status: GOOD
Description: Eastern red-backed salamanders comprise significant biomass in many forest ecosystems in Ontario
and thus play an important role in terrestrial food webs. This species exhibits many characteristics that make them
good indicators of ecological health, including long life spans, high annual survivorship, and low birth rates, and
they are territorial with a high degree of site fidelity. Under normal conditions, therefore, population sizes at a
given location show little variation over time. Furthermore, salamanders are sensitive to various stresses that
influence micro-climates, moisture levels and air and water quality. This indicator is based on the Plethodontid
Abundance protocol developed by the Ecological Monitoring and Assessment Network. Parks Canada and Bruce
Peninsula Biosphere Association have implemented this protocol at eight monitoring stations since 2004. The
monitoring method consists of an array of coverboards arranged in a specific pattern in association with the forest
monitoring plots. Each site is visited weekly in early spring for between four and eight visits and mean number of
salamanders present per site per visit is calculated. Parks Canada assigned thresholds based on baselines of natural
variability with “good” rating as >99 salamanders/160 coverboards, 73 for “fair”, and 47 for “poor” (Patrikeev
2009). Although more data is required to assess long-term trends, between 2006 and 2008 the mean number of
salamanders at the four Parks Canada sites was 116 and therefore rated as “good”. Data from the Bruce Peninsula
Biosphere Associations program has not yet been analyzed.
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Table 3.2. Viability assessment summary of Forests.
KEY ATTRIBUTE
INDICATOR
RATING
Size
Size and extent of
characteristic ecosystems
and communities
% forest cover per subwatershed
% cover by forest type
VERY GOOD
FAIR
Landscape Context
Landscape pattern (mosaic)
and structure
% interior forest per subwatershed
Age class distribution
Forest patch connectivity
Ecosystem connectivity
Regional forest connectivity
Habitat connectivity for select forest species groups
Disturbance regime
Fire regime
VERY GOOD
GOOD
NOT RATED
FAIR
NOT RATED
FAIR
Condition
% exotic plant species
Species abundance and
composition
Community structure
Abundance of forest birds
GOOD
Abundance of amphibians
GOOD
Abundance of black bear
NOT RATED
Tree health (% dieback of dominant and codominant trees)
VERY GOOD
Regeneration
NOT RATED
Downed woody debris
NOT RATED
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NOT RATED
COMMUNITY CONSERAVTION AND STEWARDSHIP PLAN