Date of Award

5-2010

Level of Access Assigned by Author

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Ecology and Environmental Sciences

Advisor

Kathleen P. Bell

Second Committee Member

Kate Beard

Third Committee Member

Aram J. K. Calhoun

Abstract

In this dissertation I investigate the impacts of both growth management regulations and vernal pool protection regulations on landscape permeability for wood frogs (Rana sylvatica), a vernal pool-obligate species. Motivated by new legislation in Maine (USA) to protect vernal pools and the species that depend on them, I combined a spatially-explicit economic model of the conversion of undeveloped parcels to residential use with a landscape permeability model for wood frogs. I estimated the economic model using a Bayesian Gibbs Sampler to account for spatial error dependence and used the results to predict future landscape patterns in a focal town, Falmouth, Maine, under different growth management and vernal pool buffer policies. Through a series of simulated vernal pool distributions, I also examine the importance of the degree of clustering of pools on the effectiveness of pool buffers. I also produced buildout scenarios for the focal town assuming cluster zoning and conservation zoning. I analyzed each of these predicted landscapes using the landscape permeability model to assess the resulting functional connectivity of the future landscapes at three scales based on the life cycle of wood frogs. Specifically, I examined connectivity between breeding pools, between breeding pools and non-breeding habitat, and between clusters of breeding pools. The results suggest that vernal pool buffers offer moderate protection at the breeding pool level but less protection to amphibians migrating beyond breeding pools. Open space requirements in subdivisions also appear capable of improving permeability for migrating amphibians, but they are generally less effective than breeding pool buffers. Nonetheless the differences in permeability across different levels of open space and the interaction between buffers and open space requirements suggest that different land use planning and open space policies may alter the effectiveness of buffer zones across space and across jurisdictions. The results suggest the need for a multi-scale approach to pool-breeding amphibian conservation and point to conservation zoning as a promising multi-scale approach.

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