Modeling avian responses to changes in land-use practices at the landscape level
White, Craig George
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I examined the influence of the landscape structure and composition, as well as modifications to Conservation Reserve Program (CRP) pine plantings, on the avian community (northern bobwhite [Colinus virginianus], songbirds, and eastern wild turkey [Meleagris gallopavo silvestris]) in a Southeastern landscape dominated by agricultural and silvicultural practices. Modifications to CRP pine plantations (thinnings and openings) were designed to simulate current CRP recommendations for already established pine plantings. Predictive models were developed based on correlation of habitat characteristics and nest locations, avian indices, and wildlife movements. The study was aided by the use of radio-telemetry, GIS, remote sensing, and multivariate analysis. Components of landscape structure that were important in predicting nest site selection of bobwhite at different spatial scales were patch density and open canopy planted pine. Songbird abundance within pine plantings was predicted by patch density within the landscape. The percentage of early successional and hardwood habitat and the interspersion of habitat types in the landscape predicted songbird richness within pine plantings. For wild turkey, hardwood land cover was overwhelmingly the best predictor of female breeding, female post-incubating, and male post-breeding activity. The male wild turkey breeding model predicted (81.35% after cross-validation) avoidance of field/hardwood edge and agriculture/closed-canopy planted pine edge, and shorter distances to closed-canopy planted pine/field edge during the spring than random locations. I also provided land managers with accessibility to a model developed from vector GIS data, which predicts wild turkey nest locations using raster GIS data. The ability of the model to discriminate nesting sites from random sites using satellite data was almost equal to model results using original vector data (73.7 % vs. 79.0 %). Results from this study support mechanically modifying CRP pine plantings to include openings and low tree densities and thus create a diverse vegetative structure within the plantings. Results also indicated the importance of considering the mosaic of habitat types in the landscape immediately around pine plantings. This study is one of the first to examine the effects that modifications to CRP, pine plantations, and subsequent landscape changes have on populations of northern bobwhite, songbirds, and eastern wild turkeys in the Southeast.