Neutral theory as a predictor of avifaunal extinctions
following habitat loss
|
The worldwide loss of natural habitat leads not only to the loss of endemic species but also to further and protracted extinctions in the reduced areas that remain. In the neutral model we derive an exact solution for the rate of loss of species in a closed community. The simple closed-form solution exhibits hyperbolic decay of species richness with time, which implies a potentially rapid initial decline followed by much slower rates long-term. Our empirical estimates of extinction times are based on published studies for avifaunal extinctions either on oceanic islands or in forest fragments which span a total of six orders of magnitude in area. The formula's predictions agree well with observed rates over three orders of magnitude of area (between 100ha and 100,000ha) both for islands and for forest fragments. |
| Back: Japanese / English |