The role of dispersal in Florida Key deer metapopulation dynamics
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Metapopulation dynamics of species that occur in patchy or island subpopulations are an important consideration in the conservation of endangered species. Key deer (Odocoileus virginianus clavium) are endemic to the Florida Keys and occur on 11 island-complexes in the Lower Keys from Big Pine Key to Sugarloaf Key. While deer numbers have increased notably, the majority of the population occurs on two of the islands, Big Pine and No Name Keys. Deer dispersal between islands is possible due to short distances between islands and shallow water. Key deer have been documented to actively disperse between islands but at very low rates (11% males, 3% females). However, increased population densities could possibly increase dispersal rates as island populations on Big Pine and No Name Keys approach carrying capacity. We examined the probability of deer colonization of peripheral islands using a sex- and stage-structured metapopulation model. Our objectives were to (1) evaluate the effects of distance and dispersal rate on Key deer island subpopulations and (2) estimate the probability of Key deer colonizing surrounding islands with viable populations. Results suggest that over the next 20 years, the Key deer population could colonize 6 of the 11 island-complexes with viable populations. However, of the remaining five islands, three lack the resources to support a minimum viable population, and while Cudjoe and Sugarloaf Keys have the potential to support >200 deer each, they are not projected to increase to above 50 deer by 2021 regardless of dispersal rate due to distance from source population. © 2005 Elsevier B.V. All rights reserved.
author list (cited authors)
Harveson, P. M., Grant, W. E., Lopez, R. R., Silvy, N. J., & Frank, P. A.