Document: MAR-3-65-32

The effects of habitat destruction in finite-patch landscapes: A chain-binomial metapopulation model.

HILL, M.* and H.CASWELL

Woods Hole Oceanographic Institution, Woods Hole MA 02543 ¹

Abstract:
We present a new stochastic model for metapopulations in landscapes with a finite but arbitrary number of patches. The model, similar in form to the chain-binomial epidemic model, can describe the effects of habitat destruction in finite patch landscapes. The model is an absorbing Markov chain (where extinction is the absorbing state), and includes a function describing the ability of propagules to search for suitable patches to colonize. We show how to calculate quasi-equilibrium patch occupancy frequencies (), mean extinction times (), and survival probabilities (l(t)) as a function of the number S of suitable patches. We found: (i) that habitat destruction can lead to short term increases in when S is small, (ii) that increasing the searching ability of propagules increases the amount of habitat destruction the metapopulation can tolerate, (iii) that is an exponential increasing function of S, and (iv) that l(t) declines rapidly from 1 to 0 over a small range of habitat destruction. Our results show that and (l(t) are highly sensitive to changes in S. These measures provide a better assessment of metapopulation viability than patch occupancy frequencies.

Keywords: Metapopulation models, habitat destruction, stochasticity, extinction times, survival probabilities.

This abstract is being presented at: 10:45 AM in session:
Oral Session #56: Metapopulation Analysis.