Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Adriana Dinu, Regional Practice Leader Environment and Energy
October 12th, 2010
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Proprietary and Confidential. Not For Distribution Without Prior Written Permission.
MANAGING ECOSYSTEMS TO IMPROVE
RESILIENCE
Putoransky, Taimyr
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Overview
What is Ecosystem Resilience?
- Definitions
Why is Resilience important?
- Key drivers of biodiversity loss
- Tipping points
- Loss of Resilience could lead to collapse
Managing for ecosystem resilience
- Landscape planning
- Grasslands
- Forests
Nalichevo Park, Kamchatka
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
What is Resilience?
Materials science: property of returning to the original shape after deformation
that does not exceed the elastic limit
Psychology: the positive capacity of people to cope with stress and catastrophe
Ecology: capacity of an ecosystem to persist in the face of disturbance
• cope with disturbances (storms, fire) without shifting into a qualitatively
different state
• withstand external pressures and reorganize, so as to still retain the same
function, structure, identity and feed-backs
A resilient ecosystem is able to maintain its ‘identity’ in terms of taxonomic
composition, structure, ecological functions, and process rates
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Without resilience, ecosystems become vulnerable to the effects of
disturbance that previously could be absorbed
Climate change, interacting with other land use pressures, might
overcome the resilience of even some large areas of primary ecosystems,
pushing them into a permanently changed state.
Past an ecological ‘tipping point’, ecosystems could be transformed into
a different type, and, in extreme cases, a new ecosystem state.
The new state may be biologically and
economically impoverished, and irreversible.
Why is Resilience Important?
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Drivers of biodiversity loss
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Changes in ecosystem structure and function: Aquatic
freshwater habitats, wetlands, Arctic and alpine
ecosystems;
Bogs, mires and fens - most vulnerable - 50 % affected
(concern as they are important carbon stores);
Snow, ice and frozen ground: increased number of
glacial lakes; increased ground instability in permafrost;
Approx. 10% of species at high risk of extinction for every
1°C rise in global mean temperature;
Amphibians - 45 % of species negatively affected
Current Impacts of CC on Biodiversity
Ecosystems are approaching tipping points
Shift to a new state
Difficult to predict
- Approach may be accompanied by slow, subtle
changes, vs. the rapid, drastic changes that
occur when a tipping point is reached -
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Climate Tipping Points and Thresholds
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Climate Change and Other Pressures: Driving
BD to Tipping Points
Source: GBO-3
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Example : Grasslands exposed to over-grazing
Original state
High biodiversity
Native grass
Grass dominated system
High economic value
Altered state
Low biodiversity
Invasive species – weeds
Shrub dominate system
Low economic value
Even when grazing pressure is relaxed, there may be little change in
composition, because of the advantage of woody vegetation over grass when the
woody is dominant
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Example : Coral reefs exposed to nutrient pollution
Original state
High biodiversity
Coral-dominated NPP
Medium productivity
High economic value
Biggs et al (in prep) Sourcebook in Theoretical Ecology
Altered state
Low biodiversity
Algae-dominated NPP
High primary productivity
Low economic value
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Example : Lakes exposed to nutrient pollution
Can be reversible – controlled by P input; irreversible shifts between stability domains
Oligotrophic
Low primary productivity
Low nutrient content
High Drinking water quality
High biodiversity
High economic value
Eutrophic
High primary productivity
High nutrient content – algal bloom
Poor Drinking water quality
Low biodiversity
Low economic value
Anthropogenic:
nutrients input from
agriculture,
sewage…
Natural causes: in aging
lakes – building-up
concentration of plant
nutrients
Slow process – over
centuries.
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Key points in understanding resilience
Climate patterns of the past will not be the same in the very near future and will
continue to fluctuate.
Reversibility and irreversibility of ecological states, and likelihood of regime
shifts.
Landscape scale is critical for maintaining resilience across different ecosystems
Management actions and land use decisions may increase or decrease resilience.
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Planning at a landscape level to maintain large
scale resilience of ecosystems
Biodiversity conservation is essential as insurance to maintain resilient ecosystems and
ensure a sustainable flow of ecosystem goods and services to society.
Existing PAs are unlikely to incorporate the long-term and large-scale dynamics of
ecosystems. Conservation strategies have to incorporate land managed for human
use.
Present static PAs should be complemented with dynamic reserves, such as ecological
fallows and dynamic successional reserves, that are part of ecosystem management
mimicking natural disturbance regimes at the landscape level.
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
External memory
- Sources for
colonization-
Ecological Memory – key component of resilience
Internal memory
- Biological legacies –
sources for
regeneration
Dispersal filtersActing in patch
Between siteWithin site
-needed for ecosystems to reorganize after large-scale disturbances;
-composed of: species, interactions and structures that make ecosystem reorganization
possible, and its components may be found within disturbed patches as well in the
surrounding landscape.
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Temporal and spatial scale in resilience planning
Developing landscape plans and policies requires a historical understanding of how the
current ecosystem arrived at its current condition.
Need for a new framework of adaptive governance that:
- embraces uncertainty and change;
- builds knowledge and understanding of ecosystem dynamics, including resilience;
- develops management practices that measure and respond to feedback
loops, including ecological thresholds; and
- supports flexible institutions and social networks in multi-level governance systems.
• (Hughes, 2005)
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
10 principles for maintaining landscape-scale resilience
Maintain and create large, complex patches of vegetation and small areas of native
vegetation keystone structures
Maintain structural complexity and mimic the matrix of natural vegetation patterns
Create buffers around sensitive areas or buffer patches around native vegetation
Maintain or create corridors or stepping stones to improve connectivity
Maintain landscape scale heterogeneity and capture environmental gradients
Source: Fischer, J., et al., 2006.
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
10 principles for maintaining landscape-scale resilience
Maintain key species interactions and functional diversity by identifying keystone
species and key seed dispersal agents
Apply appropriate disturbance regimes (e.g., fire regimes, hydrological flow regimes)
Control aggressive, over-abundant invasive species
Minimize threatening ecosystem-specific processes
Maintain species of particular concern (e.g., highly threatened/rare species)
Source: Fischer, J., et al., 2006.
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Forest resilience
Resilience of a forest ecosystem is determined by the:
• diversity of species
• genetic variability within species
• regional pool of species and ecosystems
• size of forest ecosystems - the larger and less fragmented, the better
• condition and character of the surrounding landscape
Primary forests are more resilient than modified natural forests or plantations
Some degraded forests, especially those with IAS may be stable and resilient
• They can become serious management challenges if attempts are made to re-
establish the natural ecosystem to recover original goods and services
Some Forest s with naturally low species diversity have a high resilience
• Boreal pine forests : are highly adapted to severe disturbances, and their dominant
tree species have a broad genetic variability that allows tolerance to a wide range of
environmental conditions
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Managing Forest ecosystems for resilience
Maintain genetic diversity in forests: by avoiding practices that select only certain
trees for harvesting based on site, growth rate, or form
Maintain stand and landscape structural complexity: using natural forests and
processes as models
Maintain connectivity across forest landscapes by reducing
fragmentation, expanding protected area networks, and establishing ecological
corridors.
Maintain functional diversity and eliminate the conversion of diverse natural
forests to monotypic or reduced-species plantations.
Reduce non-natural competition by controlling invasive species and reduce
reliance on non-native tree crop species for plantation, afforestation, or reforestation
Maintain biodiversity at all scales and components
Ensure national and regional networks of scientifically
designed, comprehensive, adequate, and representative protected areas.
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Work at the Landscape level
Include all grassland types across environmental gradients in protected areas: as
we do not know precisely which grassland types will be most sensitive to CC
Protect relict and native-dominated communities: as models for habitat restoration
and help in understanding how grasslands altered vs. unaltered are affected by CC.
Minimize fragmentation by land use changes and roads: protect core grassland
habitats distant from roads and human disturbances; time road maintenance to avoid
spread of invasives; monitor roadside vegetation.
Improved Connectivity: to facilitate the migration of species in response to CC - where
it is critical for maintaining gene flow among populations of rare species
Low-intensity, sustainable grazing practices: where native species are adapted to it;
Reduce/remove grazing from sites where the predominant native species lack a long
evolutionary history of grazing by large hooved herbivores; Maintain heterogeneity of
management at the landscape and mimic grazing patterns of native herbivores;
Managing Grasslands/Steppes for resilience
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Prevent and control the spread of invasive species: focus on the causes of invasion
Restoration and reintroductions of native species: IAS control, inoculations with soil
biota for native plant vigor, nutrient cycling ; restoration of native disturbance regimes
Maintenance of natural fire regimes: influences health and heterogeneity
Provide buffer zones: for shifting of populations to lands bordering reserves as
conditions inside reserves become unsuitable; act as barriers to the spread of new
invaders away from roads.
Identify and protect functional groups and keystone species: increased tolerance to
environmental extremes and recovery potential as native species richness increases.
Protect climatic refugia at multiple scales: so they can again function as refugia
during present and future CC
Managing Grasslands/Steppes for resilience (contd)
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Designing conservation strategies for resilience
• Landscape Approaches
• Working at all institutional scales – international, national, local; private, public
• Maintain or restore ecological function
• Allow redundancy and inefficiency in the system
• Pay attention to disturbance – don’t exclude them; keep them from propagating
• Implement adaptive management strategies– Explicit goals; provisional hypotheses; data gathering; evidence-based decisions;
– Monitor key ‘slow variables’
– intervene in dynamics only where unacceptable and irreversible change is otherwise unavoidable
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
Take home messages
Resilience is not good or bad; it depends on your objective
We are currently generally unable to precisely predict the position of thresholds
leading to regime shifts, but we know they occur
We do know some generalised attributes of systems that promote or erode
resilience
High efficiency and high connectivity reduce resilience to external shocks
Functional diversity and redundancy increase resilence
Annual meeting of Biodiversity Projects, Bratislava 12 – 14 October 2010.
THANK YOU!!!
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