TROPICAL RAINFORESTS: Disappearing Opportunities

Presence Does Not Always Signify Survivability in Degraded Forest

The presence of certain species in an area of degraded forest can be misleading in trying to interpet their resiliency to forest disturbance. In some cases disturbed forest may provide enough resources for a species to exist but not maintain a positive population growth rate. Their presence in the forest patch (known as a population sink) is only maintained by continued migration from an adjacent source population in an area of undisturbed or higher quality forest (known an a population source). Though the behavior and population densities of the two areas may be similar, the population of the degraded habitat can not be sustained without the source population.

If the high quality habitat is disturbed and there are no other adjacent habitats of suitable quality, both populations will be lost and the species will become extinct in the area. This is an important consideration for wildlife conservation through sustainable development schemes. For some species to persist, there must be corridors connecting intact habitats with secondary forests.

Continued: Extinction

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