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 1. Details of Module and its Structure

Module Detail

Subject Name < Botany>

Paper Name <Ecology>

Module Name/Title < Biodiversity Drivers>

Pre-requisites <Basic knowledge about biodiversity, its status, monitoring, and

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Content Reviewer (CR) < N.S.R. Krishnayya>

Language Editor (LE) <Dr. A Y Latey> Savitribai Phule Pune
University

Biodiversity
Ecology
Biodiversity Drivers
 TABLE OF CONTENTS(for textual content)

1. Major drivers of biodiversity change

2. Biodiversity management approaches
3. References

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 F
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process on its own has varying negative effects on biodiversity such as a reduction in carrying
capacity (coming from the loss in natural habitat), decline in abundanceor reduction in adaptive
nature of the species. Inset: a fragmented forest reserve in the northeast Brazilian Amazon in
2004 succumbing to fire. (b) Ecosystems show about different pressurising processes acting
synergistically. An additive model simply sums up negative impacts of all the processes. In
reality this may not happen exactly in a similar manner. Additive impact can differ from one
situation to another. At times multiplicative impact, partial or non additive impact can also be
seen. Larger additive or multiplicative impacts can significantly lower population size (at times
lower than Minimum Viable Population) increasing the extinction risk of the species. Some of
the species can continue over longer time scales with smaller population size (small population
paradigm) (Source: Brook et al., 2008)

Biodiversity
Ecology
Biodiversity Drivers
 These drivers of biodiversity change act either antagonistically or synergistically. In
antagonistic interactions, biodiversity will respond only to the driver to which it is the most
sensitive. In synergistic interactions, biodiversity will respond either additively or multiplicatively
to the drivers of biodiversity change.The most severe driver of changes in biodiversityis Land-use
change (Fig. 2). For example, change of tropical forests into grasslands outcomes into local
extinction of most plant species and the associated animals whose habitat is largely determined by
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Fig. 2: Relative impact of changes in major drivers of biodiversity. For the year 2100
ADexcepted biodiversity change for each biome was calculated as the product of the predictable
change in drivers multiplied by the force of each driver on biodiversity for each biome. Values
are averages of the estimates for each biome and they are made relative to the maximum change,
which resulted from change in land use. Thin bars are standard errors and signify variability
among biomes. (Source: Sala et al., 2000)

Biodiversity
Ecology
Biodiversity Drivers
 The increase in atmospheric CO2 is expected to have the largest effect on biodiversity of
those biomes where plant growth is most limited by water availability and where there is a mixture
of C3 and C4 species. These species differ in the effect of CO2 on their water-use efficiency,
differential physiological response. A hike in Nitrogen deposition may have maximum impact on
biodiversity in biomes relatively more sensitive to changes in soil Nitrogen. In Nitrogen-limited
systems, additional deposition can primarily give a combativeadvantage to plant species with high
growth rates, which then stop the slower growing species. In deserts and tropical
forests biodiversity may respond the least to supplementary Nitrogen deposition because plant
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Biodiversity Drivers
 Fig. 3:Biodiversity threatening processes show energy relative to habitat loss and fragmentation.
(a) A large population growing in a unmodified, contiguous habitat occupies all the available
niches and its long-term abundance fluctuates near full carrying capacity (K). (b) When natural
habitat is reduced (e.g. 50% area loss), total abundance declines accordingly. (c) However, this
simple habitat–abundance relationship is complicated by the spatial configuration of habitat loss.
In the given example, all remaining fragmented subpopulations might fall below their minimum
viable population (MVP) sizes even though total abundance is in the same proportion as of K as
seen in (b). As such, limited connectivity between subpopulations implies much greater
extinction risk than that predicted for the same habitat loss in less fragmented landscapes.
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Fig. 4:An example of the synergistic feedbacks which threaten species in disturbed tropical rain
forests (Source: Brook et al., 2008).

It is expected that Land-use change isto have the largest global impact on biodiversity,
mostly because of its negative impact on natural habitat availability and consequential species

Biodiversity
Ecology
Biodiversity Drivers
 extinctions. Climate change will be another important driver of biodiversity change, mostly having
a negative impact on high latitudes, polar regions. Overharvesting, smaller population sizes are
critical drivers in changing biodiversity. Future biodiversity also will have extensive alterations due
to changes in atmospheric CO2, biotic exchange, and Nitrogen deposition, with their relative
importance being regionally variable. Variability among biomes is maximal for land use, indicating
their larger sensitivity towards this driver. In contrast, changes in atmospheric CO2 showed minimal
variability because CO2 is well mixed in the atmosphere and the range of ecological responses is
quite narrow In coming decades this could augment the problem The other drivers have
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Extinctions continue through ‘ recovery’ period

Mass extinctions permit radiation and speciation of previously
subordinate taxa
Correlates of extinction Primary drivers: habitat destruction and fragmentation;
overexploitation; pollution
Secondary drivers of increasing importance: climate change;
environmental variability; invasive species
Evolved traits predispose species to extinction: narrow geographic
extent; ‘ slow’ vital rates; natural rarity; specialisation

Biodiversity
Ecology
Biodiversity Drivers
 Allee effects; inbreeding depression important but poorly quantified
Pattern and process Modern extinction rates >> background rate; nonrandom across taxa;
lags common
Causes of decline decoupled from causes of extinction
Emergence of generalists following major die-offs
Rapid modern extinctions change processes of evolution
Biodiversity loss reduces ecosystem function and leads to more
extinctions of codependent species
Role of humans Humans are agents of ‘ 6th mass extinction event,’ which started _50
000 d i t ifi d d i th t 500
ected

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large-scale changes because of various drivers.

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recommendations and management practices have been suggested for action at diverse spatial
scales, requiring participation of people at various levels. These include improved regional
institutional coordination, expanded spatial and temporal perspective, incorporation of climate
change and other potential scenarios into all kinds of planning and action (Fig. 6).Greater efforts are
to be made to focus on multiple pressures of global change drivers concurrently that are responsive
to and comprehensive of human communities.These drivers of change raise concerns about the
effectiveness of existing biodiversity protection strategies. Biodiversity conservation lean

Biodiversity
Ecology
Biodiversity Drivers
 predominately on fixed systems of protected areas, and to protect particular species assemblages are
the mandated goals of many conservation agencies and institutions and ecosystems within these
systems.

Fig. 6:Adaptation scheme involves a few key steps, each complex and requiring collaboration
among land managers, the public, scientists, funders and lawmakers. Recommendations reviewed
here address aspects of these steps, but without specifying where they fit in relation to one another.

Biodiversity
Ecology
Biodiversity Drivers
 (Source: Heller and Zavaleta, 2009)

Current changes are driving many vegetation types and individual species to loss
anddepletion in most of the protected areas.Due to human activities, landscapes on the exteriorside
of protected areas are antagonistic to the survival of many species. Projected rates of change are so
fast that in situ genetic adaptation of many populations to new climate conditions is not probablyto
be supportive nor their migration is likely to be fast enough for many species Most of the
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schedules, grazing limits,incentive programs)

3 Mitigate other threatssuch as invasive species, disintegration, pollution
4 Study response of species to climate change physiological, behavioral, demographic
Securing populations by practicing intensive management
Translocate species
5 Number of fundsincreased
6 Address scale problems match modeling, management, and experimental spatial scales
for improved predictive capacity
Improve inter-agency, regionalcoordination

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 7 Growth and maintain basic monitoring programs
Practice adaptive management
Conserve large areas, increase reserve size
8 Generate and control buffer zones around reserves
9 Construct ecological reserve networks big reserves, associated by small reserves,
treading stones
Develop improved modeling and analysis capacity i.e. more effective software,
integration with GIS, integrate greater complexity
Do integrated study of multiple global change drivers
Develop techniques for the extrare-establishment of wetlands and rivers
Increase interdisciplinary collaboration

Predict effects of directional climate change on ecosystems, communities,populations

Preserve genetic diversity in populations
Represent each species in more than one reserve
14 Create culturally appropriate adaptation/management options
Generate education programs for public about land use practices and effects on and
with climate
Develop best management practices for climate change scenarios
Institute flexible zoning around reserves
Increase investment in climate related research
Increase communication of knowledge about climate change impacts to policymakers
and stakeholders

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Ecology
Biodiversity Drivers
 Initiate dialogue among stakeholders Institute government reform (i.e. adaptive
governance)
Locate reserves in areas of high heterogeneity, endemism
Maintain natural disturbance dynamics of ecosystems
Practice proactive management of habitat to mitigate warming
Protectedges of existing preserves
Start tactical zoning of landuse to reducetheir impact on climate
Study and monitor ecotones and gradients
Study effectiveness of corridors
Use predictive models to make decisions on where to situate new reserves
15 Anticipate surprises and threshold effects i.e. major extinctions or invasions

Locate reserves so major vegetation transitions are in core

Locate reserves at core of ranges
Manage for landscape asynchrony
Manage human-wildlife conflict as change occurs
Manage populations to reduce temporal fluctuations in population sizes
Develop guidelines for climate sensitive restoration and infrastructure development
Need to increase social acceptance of shared resilience goals
Promote personal action plans among employees to reduce emissions
Protect endangered species ex situ
Protect functional groups and keystone species
Protect mountains

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Ecology
Biodiversity Drivers
 Protect primary forests
Protect urban green space
Quantify environmental susceptibility versus adaptive capacity to inform conservation
planning
Schedule dam releases to protect stream temperatures
Study changes in populations at rear of range rather than only range fronts
Study response of undisturbed areas to climate change
Study social agency and human decision making
Study time-series data on species dynamics
Substitute space for time to study the responses of species to climate change
Train more taxonomists

Biodiversity
Ecology
Biodiversity Drivers