Botkin Environmental Science Earth as Living Planet 8th txtbk

182 CHAPTER 9 Ecological Restoration
Table 9.3 GOALS, PROGRESS, AND STATUS AS OF 2006
PROGRESS IN MEETING
STATUS AS
SPECIES MITIGATION GOALS REQUIREMENTS OF 2006
California Tidal channels with 75% of the fish Met standards FWS recommended
species and 75% of the number of fish
change from
found in natural channels
endangered to
threatened
Salt-marsh Through reintroduction, at least 5 patches Did not succeed on constructed islands Still listed as
bird's beak (20 plants each) that remain stable but an introduced population on natural endangered
or increase for 3 years
Sweetwater Marsh thrived for 3 years
(reached 140,000 plants); continue to
monitor because plant is prone to
dramatic fluctuations in population
Light-footed Seven home ranges (82 ha), each Constructed Still listed as
clappeer rail having tidal channels with: endangered; in 2005,
a. Forage Species equal to 75% of the Met standards eight captive-raised
invertebrate species and 75% of the
birds were released
number of invertebrates in natural areas
b. High marsh areas for rails to find refuge Sufficient in 1996 but two home ranges fell
during high tides short in 1997
c. Low marsh for nesting with 50% All home ranges met low marsh acreage
coverage by tall cordgrass
requirement and all but one met cordgrass
d. Population of tall cordgrass that is
requirement and six lacked suffcient tall
self-sustaining for 3 years
cordgrass Plant height can be increased
with continual use of fertilizer but tall
cordgrass is not self-sustaining
Note: FWS stands for U.S. Fish and Wildlife Service
Critical Thinking Questions
1. Make a diagram of the food web in the marsh showing how
the clapper rail, cordgrass, invertebrates, and nitrogen are related.
2. The headline of an article about the Sweetwater Marsh project
in the April 17, 1998, issue of Science declared, “Restored
Wetlands Flunk Real-World Test.” Based on the information
you have about the project, would you agree or disagree with
this judgment? Explain your answer.
3. How do you think one can decide whether a constructed
ecosystem is an adequate replacement for a natural
ecosystem?
4. The term adaptive management refers to the use of scientific
research in ecosystem management. In what ways has adaptive
management been used in the Sweetwater Marsh project?
What lessons from the project could be used to improve
similar projects in the future?
SUMMARY
Ecological restoration is the process of helping degraded
ecosystems to recover and become more self-sustaining,
and therefore able to pass through their natural range
of conditions.
Overarching goals of ecological restoration are to help
transform degraded ecosystems into sustainable ecosystems
and to develop new relationships between the
natural and human-modified environments.
Adaptive management, which applies science to the restoration
process, is necessary if restoration is to be successful.
Restoration of damaged ecosystems is a relatively new
emphasis in environmental sciences that is developing
into a new field. Restoration involves a combination of
human activities and natural processes. It is also a social
activity.
Disturbance, change, and variation in the environment
are natural, and ecological systems and species have
evolved in response to these changes. These natural
variations must be part of the goals of restoration.