Environmental Engineering Reference
In-Depth Information
Figure 8-28
Natural capital restoration:
in the mid-1980s, cattle had degraded the vegetation and soil on
this stream bank along Arizona's San Pedro River (left). Within ten years, the area was restored through natural
regeneration after banning grazing and off-road vehicles (right).
■
Rely on pioneer species, keystone species (p. 154),
foundation species, and natural ecological succession
to facilitate the restoration process.
■
Control or remove harmful nonnative species.
Some analysts worry that environmental resto-
ration could encourage continuing environmental de-
struction and degradation by suggesting that any
ecological harm we do can be undone. Some go further
and say that we do not understand the incredible com-
plexity of ecosystems well enough to restore or man-
age damaged natural ecosystems.
Restorationists agree that restoration should not
be used as an excuse for environmental destruction.
But they point out that so far we have been able to
protect or preserve no more than about 7% of nature
from the effects of human activities. Ecological
restoration is badly needed for much of the world's
ecosystems that we have already damaged. They also
point out that if a restored ecosystem differs from the
original system, it is better than nothing, and that in-
creased experience will improve the effectiveness of
ecological restoration.
Costa Rica is the site of one of the world's largest
ecological restoration
projects. In the lowlands of its Gua-
nacaste National Park (Figure 8-24), a small tropical
dry deciduous forest has been burned, degraded, and
fragmented by large-scale conversion to cattle ranches
and farms.
Today, it is being restored and relinked to the rain
forest on adjacent mountain slopes. The goal is to elim-
inate damaging nonnative grass and cattle and reestab-
lish a tropical dry forest ecosystem over the next
100-300 years.
Daniel Janzen, professor of biology at the Univer-
sity of Pennsylvania and a leader in the field of
restoration ecology, has helped galvanize international
support and has raised more than $10 million for this
restoration project. He recognizes that ecological
restoration and protection of the park will fail unless
the people in the surrounding area believe they will
benefit from such efforts. Janzen's vision to have the
nearly 40,000 people who live near the park become an
essential part of the restoration of the degraded forest,
a concept he calls
biocultural restoration.
By actively participating in the project, local resi-
dents reap educational, economic, and environmental
benefits. Local farmers make money by sowing large
areas with tree seeds and planting seedlings started in
Janzen's lab. Local grade school, high school, and uni-
versity students and citizens' groups study the park's
ecology and visit it on field trips. The park's location
near the Pan American Highway makes it an ideal area
for eco-tourism, which stimulates the local economy.
The project also serves as a training ground in
tropical forest restoration for scientists from all over
the world. Research scientists working on the project
x
H
OW
W
OULD
Y
OU
V
OTE
?
Should we mount a massive
effort to restore ecosystems we have degraded even though it
will be quite costly? Cast your vote online at http://biology
.brookscole.com/miller11.
Science Case Study: Ecological Restoration
of a Tropical Dry Forest in Costa Rica
A degraded tropical dry forest in Costa Rica is being
restored in a cooperative project between tropical
ecologists and local people.
