control soil erosion. Kudzu had no natural enemies there and was able to outcompete native
species of vines and take over their niches (Figure23.18).
Figure 23.18: Kudzu, a Japanese vine, introduced intentionally to the southeastern United
States, has outcompeted the native vegetation. ( 8 )
As already discussed in the Communities lesson, the competitive exclusion principle states,
that if niche overlap occurs, either one species will be excluded, character displacement will
occur (as in Darwin’s Finches), or extinction occurs.
Habitat
Thehabitatis the ecological or environmental area where a particular species lives; the
physical environment to which it has become adapted and in which it can survive (Figure
23.19). A habitat is generally described in terms of abiotic factors, such as the average
amount of sunlight received each day, the range of annual temperatures, and average yearly
rainfall. These and other factors determine the kind of traits an organism must have in order
to survive there (Figures23.20and23.21).
Habitat destruction is a major factor in causing a species population to decrease, eventually
leading to it being endangered or even going extinct. Large scale land clearing usually results
in the removal of native vegetation and habitat destruction. Poor fire management, pest and
weed invasion, and storm damage can also destroy habitat. National parks, nature reserves,
and other protected areas all provide adequate refuge to organisms by preserving habitats.
TheEnvironmental Problemschapter will discuss habitat destruction in further detail.