Biology Reference
In-Depth Information
Fig. 5.5
The role of alien species in designed habitat. In Mauritius, since the early 1980s c. 40 ha
of forest have been weeded and partly fenced. These plots of designed habitat, known in Mauritius
as Conservation Management Areas (CMA), typically cover only a few hectares and are embed-
ded in a matrix landscape dominated by alien species. These CMAs are intended to mimic the
prehuman habitat states, are almost completely composed of native vegetation, but are dependent
on constant human intervention such as weeding or fencing against invasive animals such as rats
or monkeys (Photo Christoph Kueffer)
high frequency management) and habitat conditions (e.g., high light availability
combined with low soil fertility) may provide invasion opportunities for specific
types of invaders.
5.6.3
Impact of Alien Species and Management Action
In the case of designed habitat, alien species may be deliberately introduced to
restore degraded soils, remove surplus nutrients from abandoned agricultural land,
provide perches for birds or shading and nurse trees for regenerating plants, or
enhance seed dispersal, among many others (D'Antonio and Meyerson 2002; Ewel
and Putz 2004). A major concern is the possibility that deliberately introduced spe-
cies of an ecological design project may spread to other conservation areas. This
risk may be particularly high because alien species best suited for ecological design
