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The Effect of Climate Change on
Biodiversity, Forestry and Conservation
Recommendations for DPI/NGO.
This report is preliminary and In 2009,
this working group plans to explore this
question in depth.
Current authors: Jennifer Lanier, Paul
Leadley, Dominique Bachelet, Larry
Roeder
I. Introduction
Climate change is an issue as complex
and challenging as any that humans have
yet faced. Methods to predict global
climate change are growing more
sophisticated, and projections
increasingly anticipate severe
consequences for a wide range of biota,
including climate-related extinctions
(Root et al. 2003; Parmesan and Yohe
2003; Walther 2004; Walther et al. 2002;
Pounds et al. 1999, 2006). Whether these
effects may have both positive and
negative results is outside the purview
of this paper. What is within our remit
is the expected dramatic evolution shift
that will push the limits of
survivability.
However, few evidence-based strategies
exist that may help human and natural
systems adapt to climate change. The
existing static network of protected
areas, and associated conservation
strategies, is inadequate for helping
dynamic systems and their current
assemblages of species to persist in the
fact of abrupt climate change. Even
optimistic carbon mitigation and
sequestration scenarios estimate that
global temperatures will continue to
increase for 80-100 years. Clearly, we
cannot wait and expect that someone else
will solve the dilemmas presented to
human and natural systems by climate
change.
II. Problem Statement
Evolution generally occurs naturally,
everyday in small almost unperceivable
steps. There are numerous events that
speed up or otherwise change the
dynamics of evolution, either on a
global (asteroid strike) or regional
(Industrial Revolution) scale. There are
at least three general assumptions about
Climate Change: 1) That the effects will
be global but unevenly distributed; 2)
That change will be punctuated by abrupt
events (e.g. droughts, floods,
outbreaks,, human conflicts); and 3) in
relation to normal evolution changes
will be very rapid with the potential to
push every living organism and system to
their limits. It is this extreme and
rapid change that is of greatest
concern.
As the effects will be global and will
affect human habitat and economies, it
is important to identify where these
effects may and may not occur. It is
most certain that niche environments
(tundra), jurisdictions with limited
resources or influence (developing
world), boundary locked people and
animals (islands, mountain tops) will
potentially be affected the most.
Agreements of cooperation and
action-based preparedness are critical
to mitigate these aggravating
circumstances. For example, water is
already the most limiting resource for
human activities and native species.
With increased predicted temperatures
and periods of drought, the competition
between individuals (humans, fauna, and
flora) for water will increase. This has
the potential for greater conflict
between individuals, and for putting
additional pressure on communities and
nations. These conflicts and pressure
will be evident at all levels of life
for all species and systems affected,
from soil organisms, to humans, from
plant communities to nations. .An
alternate way to look at the
complexities and issues is to look at
the niche instead at a single issue such
as water availability.
The Greater Yellowstone Ecosystem (GYE),
in the USA, is a macro niche spanning
73,000 km2 and three states. It is a
mosaic of state, federal, and private
lands, and contains two national parks,
seven national forests, and three
national wildlife refuges. The ecosystem
is home to the highest concentration of
mammals in the lower 48 states. The
Rocky Mountains, with their complex
topography, are the core of the GYE and
are expected to act as important refugia
for wildlife and plants in the face of
climate change. Aggravation of any one
critical stressor such as increased
fragmentation, due to human activities
or Climate Change, of the GYE will
hinder floral and faunal responses to
climate change in general. The GYE case
study can provide insight into how
climate change strategies might be
applied across multiple jurisdictions,
and how barriers to coordination can be
overcome. This macro niche and extant
importance becomes greater when
considering migratory species.
Without some form of agreement and
mitigation planning most responses to
the pressures and conflicts will remain
reactionary responses and not address
the underlying issue. As it is true that
in the overall timetable of earth,
societies, species (Alley et al. 2003;
Benton and Twitchett 2003) and
environmental systems will find balance,
as a species, under stress, we can not
afford to sit and wait a few hundred or
million years for a ‘natural
equilibrium’. As we are partially
responsible for the current climate
change, and have a vested interest in
the short and long term future,
constructive strategies and actions are
needed to diminish negative and enhance
positive effects of Climate Change.
The following are areas of concern or
understanding needed to address the
underlying issues:
Novel climates, uncharted portions of
the climate space, novel flora
communities, possible mismatch with
preserves, static parks delineation
(Williams and Jackson 2007)
Uncertainty about where species will
move because we know about realized
niche not necessarily fundamental niche
(Loehle 1996)
Corollary to previous statement: There
is no equilibrium, nature is dynamic and
so is species range (Hannah et al. 2007)
Refugia will maintain some species, how
do we identify refugia and at what
scale?
Complex topography will help buffer
Climate Change impacts: quote from
Hamann and Aitken
“Protected areas that have a large
elevation range may be able to buffer
against climate change because species
can migrate over short distances to
entirely different habitat conditions.”
Mortality/establishment depend on
extreme events (wet year in desert area
for seedling establishment, LT drought
for diebacks, fire for serotinous cone
species, combination of fuel-building
wet years and fuel-drying year for stand
replacement fires)
Migration vs adaptation
Invasives with long distance dispersal
can rapidly occupy new potential habitat
under climate change and successfully
outcompete remnant native populations
and transform biogeochemical cycles
affecting the direction of natural
succession.
III. Current Situation
**Are there examples of static,
territory based, myopic efforts?**
Example, of good but limited efforts? Do
we want examples?** In 2009, this
working group plans to explore this
question in depth.
Innovative processes are being
developed. For example, in the US a
group of varied stakeholders with
international experience have formed The
Climate Change Conservation
Collaborative Solutions Group (C4) to
actively address potential issues.
***Need examples from around the
world**** In 2009, this
working group plans to explore this
question in depth.
The tools: strengths and limitations
Species distribution models (Araujo et
al. 2004, Williams et al 2005, Lawler et
al.) are useful tools to simulate
potential range shifts but they assume
that species ranges are in equilibrium
with climate. These models are based on
the realized niche of the various
species and can thus underestimate
future ranges as new climates create new
conditions these species may thrive in.
On the other hand, these models are
static and may overestimate future
ranges if between two periods of
projections of range, extreme events
(ex. droughts) causes the extinction of
the species. Several efforts are now
underway to link dynamic vegetation
models that can be used to track habitat
response to climate with species models
projection range contractions and
expansion.
GARP: genetic algorithm for rule set
prediction – species distrib model using
multiple statistical and rule based
techniques to project range changes
GAM: generalized additive modeling –
statistical modeling technique
climate envelope modeling (Schwartz et
al. 2001, Hamann and Wang 2005)
conservation planning software systems
SITES (Williams et al 2000)
Worldmap
Climate change scenarios
general circulation models (GCMs)
GCMs were designed to simulate the
climate of the earth. They include
state-of-the-art understanding of
atmospheric and ocean physics and
chemistry principles. Given their level
of complexity, they are
computer-intensive and provide
coarse-scale projections of future
climate on the planet. Ecologists have
been downscaling these large scale
projections to the regional and even
local level for which climate models
were not designed to simulate. Because
GCMs assume homogenous vegetation cover
and topography, downscaled information
continues to assume limited feedbacks
between actual land cover or ocean
fluxes and the atmosphere. Coastal areas
are either represented as pure ocean
cells or pure land cells in climate
models at coarse scale. Complex
topography also renders projections
inadequate to project the future of
potential refugia such as valley bottoms
protected from regional warming by cold
air drainage, inversion layers and other
locally important cloud cover dynamics.
regional climate models (RCMs)
RCMs which provide finer resolution
projections are initialized with
boundary conditions driven by GCM output
and thus include similar limitations.
arbitrary scenarios
The vast majority of models of the
impacts of climate change on
biodiversity have focused on the effects
of long-term climatic trends. There is
growing concern that the occurrence of
extreme climatic events such as drought,
extreme ocean temperatures and
hurricanes may increase in the future
and that these events will play an
important role in driving mortality.
Examples of this include the recent
episodes of severe coral reef bleaching
due to extreme sea surface temperature
anomalies (Hoegh-Guldberg et al 2007) or
forest dieback in temperate forests due
to extreme heat and drought (Breda et al
2006, Breshears et al 2005). Extreme
climatic events pose two challenges for
biodiversity modelers.
First, extreme climatic events are
difficult to model because of their very
nature of being rare events in space or
in time. The simulation of extreme
events is an area of active research
within the climate community, but much
of the most recent work has not yet been
used by the biodiversity modeling
community. Secondly, many models are not
designed to handle extreme events. In
particular, the statistical
relationships between distribution and
climate in niche-based models are
typically based on long-term averages of
climate and distribution making them
difficult to apply to extreme climatic
events. However models such as forest
gap-dynamic models or DGVMs contain the
mechanisms to account for some types of
extreme events on trees or plant
functional groups,. Several novel types
of models are also now under development
and may provide the mechanisms to
simulate the response of a large number
of species or functional groups to
extreme events.
Emission scenarios: predictability of
societal and political choices
Climate change impacts models
Dynamic global vegetation models: PFTs
vs species: DGVMs were designed to
simulate the impacts of climate change
on global land cover to eventually
provide biofeedbacks to the GCMs.
Instead of providing snapshots of
species location on the surface of the
planet like species (climate envelope)
or biogeography models do, they provide
a continuous projection of how
vegetation shifts and their associated
biogeochemical cycles may respond to a
change in climate and associated
disturbance regimes (fires, permafrost
melting). DGVMs however do not include
species characteristics. They focus on
functions and are more closely related
to the notion of ecosytem services than
biodiversity. They can however provide
valuable information on how habitats may
change with time following abrupt
changes such as decadal droughts, stand
replacing fires etc. It is unrealistic
to think that increasing DGVM complexity
by replacing plant functional types (PFTs)
by species will give us a better tool to
simulate biodiversity. Several efforts (IGBP
DIVERSITAS) are underway to increase the
number of PFTs to represent
underrepresented organisms such as
mosses and lichens which play an
important role in the carbon cycle and
fire regime of boreal forests or such as
wetland plants which have not been
included in most global carbon
accounting based on simulations despite
the extreme importance of their
importance as a conduit for methane
fluxes.
Forest gap-dynamic models simulate the
dynamics of species succession in
forests using empirical relationships
describing the growth and regeneration
of tree species in gaps created by the
death or removal of trees. These models
have been relatively successfully used
to reproduce past and current species
composition of temperate forests and
therefore are powerful tools for
simulating the effects of global change
on temperate tree species. They have
been less successful in describing
species dynamics in tropical forests
where a variety of other models
including "neutral" models have been
applied. There are currently a variety
of efforts to improve the representation
of the functional response of trees to
global change and to simulate mortality
and migration in gap-dynamic models (Rickebusch
et al 2007).
Gene flow models simulate the flow of
genes within and among populations (see
"NCEAS web site" for review). These
models can be combined with models of
population demography to simulate the
long-term viability of populations in
response to human disturbances such as
habitat fragmentation. More recently
these models have been adapted to
explore the genetic and phenotypic
adaptation of species to climate change
(Kramer A, pers comm.). Few other types
of models account for the possible
adaptation of plants and animals to a
changing environment. These models are,
however, difficult to parameterize and
test for more than a few species and
generally have very limited
representations of the functional
response of plants or animals to their
environment.
c. Sea level rise models: SLR vs local
subsidence
d. Earth system models: biofeedbacks,
local climate, complex topography
In 2009, this working group plans to
explore this question in depth.
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