Transcript Document

自然保育學
Restoration ecology
鄭先祐(Ayo)
國立 臺南大學 環境與生態學院
生態科學與技術學系 教授
Introduction
• Given th extensive damage already caused
by human activities, many scientists and
practitioners turn to restoration as the
primary means to conserve biodiversity.
• Meaningful execution requires some measure
of tenacity(堅毅), clairvoyance (千里眼) , and
dumb luck(運氣).
2
Contents
• Ecological restoration
• Animal reintroduction
• Restoration in marine environments
• Environmental regulations that drive
restoration practice
• Concluding thoughts
3
Ecological restoration
• Aldo Leopold initiated plant community restoration at
the University of Wisconsin Arboretum during the 1930s.
• Leopold and his colleagues restored approximately
120ha of forest and mixed-grass prairie, primarily
through manipulating ecosystem processes first, and
vegetative structure second.
• Today restoration ecology draws on all major disciplines
and sub-disciplines of the natural sciences, including
ecosystem and landscape ecology, geomorphology,
hydrology, soil science, geochemistry, animal behavior,
theoretical ecology, population biology, invasion biology,
and evolutionary ecology.
4
Fig. 15.1 the trajectory of a restoration project
may be viewed in terms of ecosystem
structure and processes. (Bradshaw, 1984)
5
Restoration is an iterative process
that includes
1. Examining preexisting, historic, and current
reference conditions prior to designing the
restoration plan.
2. Developing a restoration design or plan
3. Obtaining the necessary permits, where
relevant to perform the work
4. Implementing the design, which can include
modifications to soil, hydrology, and plant and
animal communities as appropriate.
5. Monitoring of the restored site
6
Restoration
• enhancement, reclamation, re-creation,
rehabilitation, remediation, augmentation, and
translocation.
• Rehabilitate or restore plant communities,
animal “restoration” usually is undertaken only
for species that are highly endangered, typically
through intensive ex situ breeding
reintroduction and translocation programs.
7
Role of restoration ecology in conservation
• Restoration ecology is a young and controversial (爭
議性的) discipline.
• Restoration ecology offers the opportunity to conduct
experiments that provide insights into important basic
biological questions, such as community assembly
dynamics, secondary succession, fire cycles, the role
of keystone species, and the nature of invasibility of
ecosystems.
• Insights from this type of research can be invaluable
for the management of natural areas, address issues
such as controlling nonnative species invasions,
reintroducing keystone species such as large
predators, and restoring natural disturbance regimes
such as fire cycles or flooding.
8
• A serious concern regarding ecological restoration is
its effect on the regulation of ecosystem conversion
for human purposes.
• However, pro-development forces increasingly do
view ecological restoration as an alternative on in
situ conservation.
• The ecological restoration and conservation are
complementary parts of an overall ecosystem
protection and management strategy.
• Critically, ecological restoration should never be
seen as a substitute for protection of intact
ecosystems.
9
A flowchart of the decisions made in
designing and carrying out an ecological
restoration project. (Fig. 15.2)
1. Determine restoration goal (restore what?)
2. Identify constraints (physical, biochemical
feedbacks, trophic-level interactions, species
pool, landscape, environmental changes)
3. Prioritize constraints
4. Address constraints
5. Characterize changed system
6. Maintain the system
10
Steps in designing and implementing
ecological restorations
1.
Site assessment：背景資料、包括：pollen cores, historical
accounts, survey records, and old photographs
2.
Setting goals：目標取向？限制？
3.
Design：multidisciplinary approach
4.
Implementation：
5.

when possible, local community members should be
included in implementation.

Maintaining control groups and applying treatments to
portions of the restoration site allow for adaptive
management and for statistical analysis of restoration
outcomes.
Monitoring and adaptive management

Long-term monitoring is vital to guide the adaptive
management of the restored site.
11
Restoration challenges
• Lack of knowledge
• Scale issues in restoration
• Implementation in practice
12
Lack of knowledge
• Much more information is available on birds and
mammals than on bacterial communities across the
globe, yet the success of a project may be dependent
on appropriate soil bacteria being present.
• We know that animals often play key roles in structuring
ecosystems. However, the majority of restoration efforts
are focused on plant communities.
• In many cases, a “bottom-up” approach may be the
most effective– that is, once essential ecosystem
components, such as soil structure and geochemistry,
hydrological functions, and vegetative structure are
restored, animal communities may assemble
themselves. However, suitable habitat does not by itself
guarantee the presence and viability of specific animal
populations.
13
Scale issues in restoration
• Restoration projects that focus on a small scale
may succeed in establishing native ecological
systems in the short term, but may fail in the
longer term because the large ecological
context required to allow these restoration
efforts to be self-sustaining is either not present,
too degraded, or operating at too small a scale.
• When ecosystem degradation has been
extremely intense or of great spatial extent,
restoration can be particularly difficult to
achieve (Fig. 15.7)
14
15
Implementation in practice
• Many restoration projects do not use a
multidisciplinary approach.
• Instead, they focus more narrowly on a single
taxon or a single ecosystem function.
• Restorations not only make use of scientific
knowledge, but add to it as well.
• When resources are available to support an
experimental approach and to allow long-term
data collection, ecological restoration offers
unique opportunities to add to our scientific
knowledge while increasing ecosystem
functioning.
16
Animal reintroduction
•
Well-justified reintroduction objectives
include (IUCN)
1. Enhancing the long-term survival of a
species
2. Reestablishing a keystone species
3. Providing long term economic benefits to
the local and/or national economy.
17
Guidelines designed to maximize
success
1. Conduct a feasibility study, including assessment of the
biology of the species, availability of individuals of the
same taxonomic status for reintroduction, and whether
other species have taken up the ecological role of the
species that has been extirpated from the wild.
2. Select and evaluate sites within the historic range of the
species, ensuring that suitable habitat is available that
is not subject to the same threats.
3. Identify and evaluate suitability of stock to be
reintroduced, including genetic factors.
4. Evaluate social, political, and economic conditions at
the reintroduction site to ensure that long-tem financial
and political support will be available.
18
5. Plan a properly financed reintroduction with
approval by all stakeholders, and in
coordination with management agencies.
Design pre- and post-release monitoring to
make the reintroduction a carefully designed
experiment, with the capability to test
methodology, thereby allowing improvements
for future releases.
6. Post-release monitoring should be done using
an adaptive model, ensuring that necessary
intervention can be carried out.
19
Restoration in marine environments
• Marine restoration activities are
widespread, particularly where restoration
enhances commercially important
fisheries.
– Reforestation projects to restore mangrove
ecosystems, areas cleared for shrimp ponds
and other fisheries.
– 人工魚礁
– Still in the trial-and-error stage.
– 2004, December 26, 海嘯之後，如何復育？
20
Environmental regulations that
drive restoration practice
• The financial burden of restoration is
significant, with the total cost of a typical
restoration project in the US mounting to
as much as US$3.00 per square foot, or
over US$130,000 per acre .
– Such expense renders even small-scale
ecosystem restoration projects problematic.
21
Regulations in the United States
• Clean water act (CWA), 1972
• Endangered species act (ESA), 1973
• Surface mining control and reclamation
act (SMCRA), 1977
22
International regulations
• Many countries share common elements in
their restoration-related legislation.
– For example, mining regulations require reclamation
of degraded lands in Chang, India, and Canada
• Convention on Biological diversity.
– Restore degraded ecosystems and threatened
species, with particular emphasis on forests, inland
waters, and marine ecosystems, including coral reef.
23
Concluding thoughts
• 1970s, to restore ecosystem were based not on good
science or bad science, but on no science at all.
• 1980s, many restoration efforts involve simply the
replanting of native nursery stock.
• 1990s, working in interdisciplinary teams with diverse
backgrounds and objectives, restoration ecology was
more “ ad hot” or “compromise” ecology than a science
based primarily on sound ecological principles.
• 2000s, experimentation and adaptive management of
restoration projects.
– Programs that are devoted to the training of ecosystem
restorationists.
– There is still plenty of basic science to come by to advance the
field.
24
• Increasingly, restoration may become a vital
component of conservation practice, as we seek to
improve degraded habitats.
• Coupling restoration efforts to larger conservation
efforts may offer many opportunities.
• Because restoration is itself a long-term process, it
forces us to consider how we might influence
biodiversity conservation over longer time scales.
• One of the greatest needs for future work in
restoration as a conservation tool is to increase our
capacity to learn from restoration efforts, via
comparative analyses and experimental approaches.
25
問題與討論
• Ayo 台南 NUTN 站
http://myweb.nutn.edu.tw/~hycheng/
26