Download 7 - WWF

WWF / MacArthur Foundation
Developing an approach to adaptation in the Insular
Caribbean: the hawksbill turtle as an indicator species
Outline
This document is intended to outline possible adaptation strategies for marine turtles negatively affected by
climate change effects such as increasing temperatures and sea level rise. This document intends to attempt to
exhaustively list all such options (from highest risk, least advisable, to lowest risk, most advisable, based on best
available scientific knowledge to date) and to seek comments on these strategies from a panel of experts (the
ACT initiative members). However, there are a great number of new adaptation strategies that could be used
and readers are invited to submit additional adaptation options for review. The result of this document would
be a list of adaptation options that cannot be supported by marine turtle experts and a list of adaptation
strategies that warrant further investigation and testing.
Introduction
Climate change is now well understood and documented. Modern conservation practices, however, frequently
do not yet include considerations for climate change and how to manage biodiversity protection under future
climate scenarios. For this reason, the MacArthur Foundation made a grant to the World Wildlife Fund to try
to investigate some adaptation options that could be tested and recommended in marine turtle conservation
programmes. A workshop was held in Miami in December 2007 to convene upon the latest understanding of
climate change effects on marine turtle ecology and to recommend where the most important research gaps
lie. Following on from this workshop, the ACT initiative now intends to create some recommendations for
marine turtle “adaptation strategies” to cope with the negative effects of climate change.
Adaptation – what does it mean?
Simply any means by which the negative effects of climate change on marine turtles can be mitigated.
Complicating adaptation, particularly for marine turtles, is the relative lack of understanding of the effects of
climate change, which means that some adaptation ideas could be risky.
What if we do nothing? Ultimately, we cannot predict with any certainty what effect inaction would have on
marine turtles under future climate scenarios that were warmer, with stronger storms and altered
precipitation patterns. However, published anthropogenic threats to marine turtles, such as by-catch, boat
strikes, direct harvest for eggs, meat and shell, pollution (both chemical and physical causing illnesses and
entanglement) and coastal development, could all be compounded by climate change, if climate change
threatens human socio-economic and infra-structure systems as expected (IPCC, 2007). Likewise, published
non-anthropogenic threats to marine turtles, such as predation, disease, and prey availability could be altered
by future climate change (REFS). The magnitude and direction of such compounding effects is, however, very
complex to predict with any confidence. Logic would suggest that a future scenario in which human coastal
populations were less likely or able to protect coastal natural resources due to effects of climate change on
humans (e.g. droughts, flooding, altered crop production, food production and disease) leading to impaired
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anthropogenic function (e.g. infrastructure, health care, economic development and education), and where
natural systems were altered from their current state would not be positive for marine turtle conservation.
So should we do something? Available scientific literature suggests that climate conditions may affect some
turtle behavioural patterns (Hawkes et al., 2007; Pike, Antworth & Stiner, 2006; Saba et al., 2007; Saba et al.,
2008; Van Houton & Bass, 2007). For example, turtles can begin nesting earlier if spring sea surface
temperatures are warmer (Weishampel, Bagley & Ehrhart, 2004) and if such behavioural change reduces
negative effects of climate change, it may confer an advantage. However, for other currently published threats
of climate change to marine turtles, such as temperature dependent sex determination (TSD; (Hawkes et al.,
2007; Janzen, 1994; Mrosovsky, 1984), adaptation may not occur on time scales that match the expected pace
of climate change (IPCC, 2007). Adaptation options may therefore be prudent to investigate, particularly given
that many marine turtle populations are at levels of concern, as listed by the World Conservation Union
(IUCN, 2007). Adaptation options will likely be novel and probably controversial. At their best, they should
pose least risk: for example, a strategy for reducing nesting beach erosion of replanting coastal mangrove
forests in non-nesting areas along shore from the nesting beaches would not likely negatively impact turtles if
the strategy did not work. If “no risk” strategies could be developed to mitigate effects that we expect are
likely to happen then they could be recommended and explored further.
CONTENTS
The following subheadings are designed to cover the majority of negative climate change effects to marine
turtles:
1. Available nesting beach
2. Sex ratios
3. Genetic diversity and depensation
4. Foraging sites
5. Disease and infection
6. Coastal management
7. Communications
AVAILABLE NESTING BEACH
Turtles require sufficient dry beach above the high tide line for nesting. Ideally beaches should have a sufficient
depth of non compacted sand, free from excessive vegetation roots, rocks and other items. They should also
be free of artificial light, beach obstacles (such as beach furniture) and other disturbances such as people,
vehicles and predators. Sea level rise could cause a net loss of nesting beaches, particularly in the insular
Caribbean where maximum land elevations are frequently comparatively lower than many mainland costs, with
little potential spatial refugia. Coastal development may also cause a net loss of available nesting beach since
they can prohibit landward regression of coastal areas (“coastal squeeze”). Suggested adaptation options for
mitigating against loss of nesting habitat (with space to annotate invasiveness (Inv.) and risk) are:
1
2
3
4
5
6
7
Detail
Re-seed nesting populations to alternative, more “suitable” nesting areas
Use erosion control strategies (such as sandbags, beach re-nourishment, groynes, wave
attenuation (note: coral reefs do this naturally) to mitigate beach loss
Move existing infrastructure landward to make available more nesting beach
Alter existing infra-structure management to make developed beach front areas more
turtle friendly (e.g. reduced lighting, move beach furniture off the beach at night, reduce
access at night)
Regulate new development to be more turtle friendly (e.g. turtle friendly lights, turtle
friendly beach furniture, reduced beach use at night, appropriate setbacks)
Coastal set backs used (a variety of options, informed by a GIS tool, (Fish et al., 2008)
Focus efforts on specific nesting rookeries to maintain overall genetic diversity
Inv. Risk
1
2
3
4
5
6
7
2
8
Revise coastal management and use recommendations / regulations
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SEX RATIOS
Marine turtle primary sex ratios reported in peer reviewed science literature are presented in figure 1. Despite
significant conservation effort at a wide range of nesting locations, the translation of the sex ratio of hatchlings
produced from nests into effective adult sex ratios and the accompanying population dynamics are little
understood. This means that a comprehensive understanding of what constitutes an “ideal” primary sex ratio is
not yet available. Current reported primary sex ratios, coupled with nesting metrics from a variety of nesting
rookeries suggests that marine turtles can maintain viable population fertility with proportionally few males at
large in the population (between 5 and 10%), but likely depend on exchange of individuals between rookeries
or even subpopulations that may have slightly different primary sex ratios (Bowen & Karl, 1997). Suggested
adaptation options for mitigating against extremely skewed sex ratios that could prevent fertilisation of nesting
females from adequately occurring include:
1
2
3
4
5
6
7
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Detail
Artificially incubate, ex-situ in controlled temperature (CT) rooms all marine turtle eggs for
desired sex ratios
Artificially incubate, in beach hatcheries, all marine turtle eggs for desired sex ratios by
manipulating:
i)
beach substrate albedo
ii)
beach substrate ventilation (grain size)
iii)
Shading (artificial and vegetation)
iv)
Precipitation (using watering)
v)
Clutch size (fewer eggs = less metabolic heat to likely maximum 1°C)
vi)
Flooding / water table
Adopt beach hatcheries and measure the incubation temperatures of all clutches, report
results and move nests to different thermal regimes accordingly to desired sex ratio
Measure the incubation temperatures of all clutches, report results and move nests to
hatcheries with different thermal conditions to natural nests accordingly to desired sex
ratio
Transplant all nests from hottest parts (or lethally hot conditions) of the nesting season to
hatcheries with cooler conditions or incubators to produce viable hatchlings
Head start selected rookeries of nesting populations that are known to produce a higher
proportion of male offspring
Head start selected rookeries of nesting populations that are known to consist of different
genetic stocks to maintain genetic diversity within the population as a whole
Create “thermal refugia” (selected portions of beach that have different sand albedo, grain
size, shading, precipitation patterns, flooding patterns) that would provide cooler
incubation conditions on portions of known nesting beaches that turtles could nest in.
Monitor use of these refugia and report results
Inv. Risk
1
2
3
4
5
6
8
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GENETIC DIVERSITY AND DEPENSATION
The loss of genetic diversity within a population can decrease fitness and contribute towards risk of extinction,
particularly so for populations at dramatically reduced levels (the ‘depensation’ effect’) where growth rate may
be impaired (Stephens & Sutherland, 1999). A mixed stock, one that contains a genetically representative
portion of all colonies within a population, is therefore likely the best choice to ensure resilience after an
impact and should confer better likelihood for population recovery. Suggested options for adaptation strategies
could be:
Detail
Inv. Risk
3
1
2
3
4
5
6
7
Breed in captivity and head start specific genetic stocks to maintain desired diversity
Head start specific genetic stocks of hawksbills to promote relative abundance of different
haplotypes in the populations
Translocate small numbers of males to breeding areas with different haplotype
combinations
Identify and differentially protect a representation of different haplotypes of hawksbill
turtles
Identify and differentially protect a replication of different haplotypes of hawksbill turtles
Effectively manage direct take of different genetic stocks of hawksbill turtles
Effectively ban illegal direct take of different genetic stocks of hawksbill turtles
FORAGING AREAS
The foraging habits and dietary preferences of marine turtles differ between the 7 species of turtle (Bjorndal,
1997). In this document, we will focus on hawksbill turtles, which are thought to mainly forage on sponge
species, such as the sponge orders Astrophorida and Hadromerida (Leon & Bjorndal, 2002; Meylan, 1988).
Although coral reefs are known to respond to excessively high water temperatures by bleaching (HoeghGuldberg, 1999) and that macro-algae may increase in abundance in response to disturbed coral reef systems
(Mumby, Hastings & Edwards, 2007), little is known about the effects of such altered dynamics on the diversity
and abundance of sponge species (Hill, 1998). Healthy reefs are normally defined as those in which one
observes a high proportional live coral cover, presence of crustose corraline algae (which facilitate coral
seeding), a good diversity of coral species and high biomass of fish species (Burke & Maidens, 2004; HoeghGuldberg, 1999; Hoegh-Guldberg et al., 2007; Hughes, 1994; Mumby, Hastings & Edwards, 2007). Although
some coral species (e.g. Acropora, pocillopora) are fast growing and early maturing (Baird & Maynard, 2008), the
majority of coral species are not (Hoegh-Guldberg et al., 2008). Alternative natural responses of corals to
climate change could be physiological acclimation and formation of symbioses with multiple species of thermally
tolerant dinoflagellates. However, there have been climate related mass coral mortalities in paleontological past
(Hoegh-Guldberg et al., 2008), suggesting that the ability of corals to adapt may be limited.
One assumption could be that current reef biodiversity and dynamics host sufficient prey diversity and
abundance to maintain hawksbill foraging (as evidenced by the presence of foraging hawksbills on reefs). Under
this assumption, suggested options for mitigating against dramatic alteration to current foraging sites could be:
1
2
3
4
5
6
7
8
9
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Detail
Inv. Risk
Screening / sprinkling / shading reef areas to mitigate effects of increased surface 1
temperatures and UV light penetrance
Using coral nurseries of known resilient species to re-seed reef areas impacted by localised 2
warming events
Increase the biomass of herbivorous fish species on coral reefs using nurseries / screening
3
Reduce the harvesting of herbivorous fish species on coral reefs and surrounding areas
4
Effectively protect (using MPA’s, effluent reduction and other mitigating measures) a 5
network of coral sites to enhance transport and replenishment of coral polyps between
areas
Identify and protect critical “refugia” that are protected from bleaching by natural factors 6
(e.g. shading, currents) and are exposed to a good source of replenishment
Identify and protect a representation of different types and species of corals
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Identify and protect a replication of different types and species of corals
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Effectively manage coral reef areas (reduce threats, enhance recruitment and recovery)
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DISEASE AND INFECTION
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The prevalence and transmission of infectious diseases is thought to occur at increased rates in warmer
conditions. In turtles, the etymology and spread of well recorded diseases such as Fibropapillomatosis (FP;
reviewed in (Chaloupka & Balazs, 2005) are little understood at present (REF). Potential adaptation options for
the this threat could be:
1
2
Detail
Improved agricultural practices using less chemicals
Managing effluents from agricultural practices
Inv. Risk
COASTAL MANAGEMENT
Although climate change is a well known and documented anthropogenic threat, little coastal management
policy, especially in the Caribbean, has climate change components. Further, coastal management may be
compounded by climate change threats (e.g. sea level rise, coastal development and salt water intrusion) such
that many aspects of current anthropogenic function would be impaired: for example increased frequency and
severity of both severe droughts and flooding could occur, affecting crop production and potentially causing
food shortages. Altered severity of extreme storm events and conditions afterwards could increase the spread
of diseases and affect health care and damage infrastructure such that economic development and educational
facilities could also be affected.
In the case of marine turtles and climate change, coastal management encompasses the conservation of
adequate beach space for nesting (see section 1), the protection of nesting females and their eggs, which could
be more preferentially harvested for meat and shell products, the reduction of pollutant run off in known
nesting areas and the reduction of accidental capture of juvenile and adult turtles in coastal waters. Suggestions
for adaptation options to mitigate such an effect could be:
1
2
3
4
5
6
7
8
9
10
11
12
Detail
Inv. Risk
Move existing infrastructure landward to make available more nesting beach
Alter existing infra-structure management to make developed beach front areas more
turtle friendly (e.g. reduced lighting, move beach furniture off the beach at night, reduce
access at night)
Regulate new development to be more turtle friendly (e.g. turtle friendly lights, turtle
friendly beach furniture, reduced beach use at night, appropriate setbacks)
Coastal set backs used (a variety of options, informed by a GIS tool, (Fish et al., 2008)
Increased presence of beach guards to prevent un-permitted take of nesting females
Increased presence of beach guards to prevent un-permitted take of turtle eggs
Use of beach hatcheries to protect incubating clutches
Use of managed take programmes to control take of nesting females from beaches
Use of managed take programmes to control take of turtle eggs from beaches
Improved agricultural practices using less chemicals
Managing effluents from agricultural practices
Reducing / banning the use of nets / trawls / long lines in the vicinity of turtle nesting
beaches and juvenile foraging grounds
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What next?
recommendation
The adaptation strategies in this document should be compiled, edited and completed by the WWF MacArthur
ACT initiative members and the strategies later reviewed by a different panel of experts. The reviewing
audience should rank and rate the adaptation strategies and suggest which of the strategies they most
recommend and which they suggest are inappropriate. A form will be given to each audience reviewer to add
their comments and to rate the adaptation options. To ease the process, each audience reviewer could only
review one section of the seven listed, and this would be chosen at random. The reviewing could take place by
email submission from interested parties, or by online form submission at the WWF panda ACT website.
Another suggested way to achieve this is to present the adaptation strategies for review to the next
International Symposium on Sea Turtle Biology and Conservation in Brisbane, Australia (February 2009). A
sponsored side session could be hosted, in which participants are invited to sample randomly from the seven
adaptation themes and to appraise the adaptation strategies. Each strategy should be scrutinised for a number
of different factors: i) Suitability – how suitable is this adaptation strategy? Do you think it is a good idea?
Would you recommend it? Do you think it would work and would work well? Add a ranking between 0 and 10
(where 0 means you expressly do NOT recommend that the strategy is used, 5 means you recommend it as
much as not and 10 means you think it is an excellent idea); ii) Feasibility – do you think we could actually do
this? Logistically and financially, is it just way too resource intensive? Add a ranking between 0 and 10 (where 0
means you think it just would never happen, 5 means you think it could as easily as not work out and 10 means
you think it would be simple to implement, maybe even using existing infrastructure, or it is already
underway!). The suitability and feasibility scores can be multiplied to obtain a composite score that reflects the
overall best and worst marine turtle adaptation strategies.
CHEAPEST AND MOST
RECOMMENDED
MOST RECOMMENDED BUT
MOST EXPENSIVE
CHEAPEST BUT LEAST
RECOMMENDED
NOT HIGHLY RECOMMENDED
AND EXPENSIVE
cost (time and money)
Next steps should be:
1.
2.
3.
4.
Circulate this document round all ACT initiative members for additional adaptation options;
Create a questionnaire with each adaptation strategy, grouped into the seven sections;
Sponsor a session at the ISTS / create online form submission / solicit response online;
Randomly circulate questionnaires to participants of sponsored session for recommendations for each
strategy, which cover:
a) Feasibility (how likely is it this strategy could actually be achieved?)
b) Suitability (how suitable do you think this strategy is)?
c) Recommendation (do you recommend this strategy?)?
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Appendix
1. What is adaptation?
To many biologists, “adaptation” is synonymous with beneficial evolutionary responses of species of animals
and plants; to wildlife managers it can be aligned with conservation techniques (such as adaptive management);
to donors / funding agencies it can be sequestering Carbon dioxide. In the appendix we have collected the
definitions from the dictionary, from Wikipedia, from the IPCC, from the World Bank, from the UNDP and
from the CBD. We have chosen these definitions since they are public, well read and probably therefore well
thought out. There are many others. In general, the definitions, in the context of climate change, seem to have
in common a change in a variety of processes and practices to cope with climate change impacts, all seem to
imply the inclusion of humans and all are fairly general. Most of all they are rather vague - some definitions
require definitions of their composite words (e.g. vulnerability, resistance, resilience) and are not specific. What
does and does not constitute adaptation is hard to understand from even this set of 5 definitions. This is a
problem – not only do scientists, conservationists and managers not seem to understand the term well, funding
agencies and trusts also seem to find it problematic in terms of what it specifically refers to, which could lead,
in worst case scenarios, to an under-funding of legitimate adaptation work.
Hence what we mean by “adaptation” is novel.
Inherently as scientists we need to quantify and give reasoning for conservation goals and targets, yet if the
pace of climate change occurs as in high emissions scenarios, we might not have time to collect the evidence
that would normally make us comfortable in proceeding with recommendations. In short, we are charting new
territory and are being hurried for a decision by ongoing climate change. We may need to make uncomfortable
decisions without exhaustive supporting data and recommendations and try to think about how risky each
adaptation strategy could be if it went wrong versus how beneficial it might be if it worked AND deal with a
lack of evidence to be sure about that risk. Tricky stuff…
2. What does adaptation mean in the ACT initiative?
Plainly, we mean:
What things can be done to help turtles cope with adverse effects of climate change?
So in longer terms, these would be activities that would help turtle populations to be more resistant and
resilient to climate change effects, where resistance is the ability to withstand change, and resilience is the
ability to recover after change (see section 4.). For example, an adaptation activity could include securing spatial
refugia for turtles to be able to cope with climate change without additional intervention, e.g. effectively
managed beaches and networked protected areas with sufficient marine turtle habitats; reducing pollution and
run off from agricultural practices (examples of non-climate stressors); intervening to maintain diverse gene
pools for increased resilience by prioritizing conservation at a variety of genetic sources. Adaptations may be
direct (e.g. hatcheries and manipulating sex ratios to mitigate the impact of overheating) or indirect (e.g. Marine
Protected Areas to increase the resilience of feeding sites). Adaptations may take place over large spatial scales.
Based on the above and from discussions at the WWF/MacArthur Miami workshop in December 2007 and the
WWF / Hewlett Packard Climate Camp workshop in February 2008, some specific suggestions for a marine
turtle adaptation agenda are:
1. Supporting efforts to mitigate climate stressors (e.g. WWF lobbying for emissions reductions)
2. Integrating climate change into written management policy (e.g. coastal and MPA management)
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3. Integrating the strengthening of resilience into coastal management by creating / protecting
a) Refugia (“lucky” sites that are naturally more resistant or tolerant to CC)
b) Representation and replication (protect turtles and habitats of a variety of types)
c) Connectivity (incorporate knowledge about connectivity to make sure that hatchling dispersal,
developmental areas etc. are incorporated into networks of protected areas)
d) Good conditions (good water quality, lack of diseases)
4. Reduce local stressors (usually non climate, e.g. direct harvest for meat and/or shell)
5. Protect, maintain or enhance conditions that promote ecosystem recovery (e.g. healthy reefs)
6. Engage stakeholders that benefit from marine turtles (e.g. community conservation programs)
3. Anything else I can read to figure out more?
WWF has made significant inroads into incorporating adaptation into conservation work. There are several
excellent sources of information available to support this work, which give more information about the nature
of adaptation. “Buying time” (http://assets.panda.org/downloads/buyingtime_unfe.pdf) is a manual for protected
area managers to cope with climate change effects and has some core information about adaptation. WWF has
also produced a leaflet about marine turtles and adaptation work that can be used to guide and shape the work
in
the
ACT
initiative
(http://www.panda.org/about_wwf/where_we_work/latin_america_and_caribbean/index.cfm) as well as a
library of different information about climate change and WWF’s climate change work
(http://www.panda.org/about_wwf/what_we_do/climate_change/index.cfm). For even more information, see
http://www.adaptationnetwork.org. This page (a non-profit organization and project of the Earth Island
Institute) has a short but handy discussion of adaptation. Its goal is to promote adaptation in concert with
mitigation to build resilience in future changing climate. It has some helpful publications and presentations.
4. Definitions
Resistance: the ability to withstand change
Resilience: the ability to recover from change
Adaptation: anything that increases a community’s ability to remain intact and functional in the face of
climate change
Vulnerability: Patwardhan (2006) defines vulnerability in 5 key steps, the amount of data required to
estimate, and understanding of vulnerability, increases through the list:
i.
The degree of exposure – a measure of the potential hazards, e.g. a likely range
ii.
The degree of effects – a measure of the physical impacts caused by the hazards
iii.
The degree of loss – a measure of the change in benefits caused by the hazards when nothing is done to
mitigate
iv.
The degree of least loss - a measure of the change in benefits caused by the hazards when the optimal
amount is done to mitigate
v.
The opportunity cost of inaction – the difference in loss between (v) and (iv)
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Bradbury, R.H., Dubi, A. & Hatziolos, M.E. (2007) Coral reefs under rapid climate change and ocean
acidification. Science, 318, 1737.
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(2007) The effect of the El Nino Southern Oscillation on the reproductive frequency of eastern Pacific
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Dr Lucy Hawkes
Marine Turtle and Climate Change Programme Leader
World Wildlife Fund
1061 Queen Helmut Street
Belize City, Belize, Central America
T: (501) 223-7680 / 7684
F: (501) 223-7681
M: (501) 669-8280
E: [email protected]
Belize City, March 11, 2008
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