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CAS Workshop on Ecosystem Succession Theory and Practice of Ecological Restoration Bird
conservation in riparian ecological restoration after natural resource
damage assessment Huang
Zhangzhi “Charlie” (California
Resources Agency, CDFG-OSPR, P.O. Box 944209, Sacramento, CA 94244,
USA) Abstract:
In the southwestern United States including southern California,
riparian habitats are among the most ecologically productive and
diverse environments. The
land-water ecotone creates moisture gradients that lead to a diversity
of physical environments. Dynamic
river changes create a mosaic of habitats and microhabitats.
Riparian zones are especially important in semi-arid regions
where the availability of moisture and associated microclimate give
these habitats an ecological importance to their area extent.
During the last several decades, riparian habitat in the
southern California has undergone serious decline due to water
diversions and increased development within the floodplain.
For example, about 95 percent of riparian habitat has been lost
in southern California. Urban
and suburban development, agriculture land, and invasion by exotic
plants have all reduced the extent of riparian vegetation and its
accompanying wildlife. For the degraded riparian
ecosystem, ecological restoration is needed.
Historically, ecological restoration was usually direct
mitigation for unavoidable land and plants losses.
However, bird restoration is integral to ecological restoration
because bird diversity reflects food-web consequences in a riparian
ecosystem. Migratory
birds need riparian forest for migration and breeding.
Declining bird species is caused in part by reduction and
fragmentation of forest habitats.
Bird conservation, therefore, requires large scale
reforestation, reconnection, and closure of fragmentation.
As the restoration ecology has progressed substantially in
recent years, riparian ecological restoration can include bird
conservation. Bird
restoration activities can contribute substantially to the ecological
value of riparian habitats. In January 1994, an oil pipeline
ruptured. The largest oil spill occurred in Los Angeles County.
Approximately 190,000 gallons, or 4600 barrels, of crude oil
flowed into the Santa Clara River.
The natural resources injured as a result of the spill and
resultant cleanup activities included approximately 100 acres of woody
and herbaceous vegetation and approximately 150 acres of sediment,
fishes, birds, other wildlife species, and riparian vegetation.
As required under the Oil Pollution Act, when an oil spill or
other pollution event occurs, the oil company is responsible for
compensatory restoration. A
Natural Resource Damage Assessment was performed to determine the
injuries from the spill to the natural resources of the Santa Clara
River. The appropriate
actions were required to restore, rehabilitate, replace, or acquire
the equivalent of the injured natural resources. In January, 1997, a
settlement of $7.1 million was agreed upon as compensation for natural
resource damages resulting from the oil spill.
After the settlement, a Trustee Council was formed including
federal and state agencies, whose responsibility was to develop a
restoration plan for the Santa Clara River, to allocate settlement
funds associated with that effort, and to implement successfully the
restoration projects. This settlement funding provided
opportunities for restoring riparian ecosystem of Santa Clara River.
The restoration of riparian ecosystem is a complex challenge to
many important partners. Communities,
government agencies and technical consultants all share responsibility
of developing successful restoration workplan.
The restoration project of Santa Clara needs an adaptive
management program based on restoration research (i.e., adaptive
restoration). The project
also requires technical expertise from managers, scientists, and the
public leading to implementation of ecological restoration. The scientific and regulatory
foundation of the restoration workplan is presented from a structured,
decision analysis framework. We
demonstrate the applicability of using an integrated approach to bird
conservation from the lower Mississippi alluvial floodplain to
California. A business model for bird conservation is implemented to
enhance the overall health of the ecosystem.
Central to bird conservation is a comprehensive understanding
of (1) biological foundation, (2) conservation design, and (3)
conservation delivery. The
geomatics network was established to provide a starting framework,
integrating a GIS-based user interface with a logic inference engine.
Since the oil spill in 1994,
bird studies were performed along the Santa Clara River.
Bird densities and species richness in riparian systems
demonstrated the importance of these habitats to birds.
Initially, the purpose of the studies was to assist in
determining the injuries that occurred to the natural resources as a
result of the oil spill. Since
January 1997, the focus of the bird studies shifted to restoration
planning. The information that had been gathered assisted the Trustee
Council in prioritizing areas for acquisition, protection and
restoration. Although a successful restoration workplan has been
implemented, .the bird conservation of the recommended areas is only
one step in what should be a multifaceted effort.
If riparian ecological restoration is to be effective, areas
for acquisition must be coupled with conservation, management,
long-term monitoring, and public education.
Combining a GIS with a
computer-aided site selection model, we evaluate parcels of land for
the conservation of potential habitat for bird species.
All the parcels were within the 500-year floodplain of the
Santa Clara River. Criteria
used to assess these sites included the amount and contiguity of
habitat, as well as the cost of land.
Based on an analysis of the model results, we recommended 38
parcels, clustered in two areas of the river, for purchase.
The area of these parcels totaled approximately 2000 aceas. This project will serve as a
foundation for riparian conservation along the Santa Clara River.
In the future, we will design an inference network that links
watershed-scale, riparian-scale, and local habitat characteristics
with river ecological integrity. Large, costly restorations should be approached with
scientific understanding of system function in relation to ecological
structure scales: (1) individual species, carefully (2) selected
assemblages, and (3) habitats placed strategically in the landscape.
Key words:
bird conservation; ecological restoration; natural resource damage
assessment.
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