Landscape Patterns Associated with Occupancy of Disturbance-Dependent Birds in the Blackland Prairie Ecoregion of Alabama and Mississippi
2019
Gilbert, Neil A. | Ferguson, Paige F.B.
The Blackland Prairie Ecoregion of Alabama and Mississippi, formerly a mosaic of prairie, shrubland, and forest, has undergone massive landcover change in the past 2 centuries. Even though the region is now dominated by agriculture and ranchland, disturbance-dependent birds—a guild in decline—continue to inhabit the Blackland Prairie Ecoregion. Therefore, we investigated the relationship between landscape patterns at 4 spatial scales (within 200 m, 600 m, 1000 m, and 3000 m of survey points) and occupancy for 17 species of disturbance-dependent birds. We used a Bayesian occupancy model to relate avian detections to landcover covariates and used stochastic search variable selection to identify covariates that were relevant to occupancy for each species. The amount of canopy cover was the covariate most frequently identified as relevant to occupancy. Grassland and open-country species showed a negative relationship with canopy cover, while shrubland species showed a positive relationship with canopy cover. The association between occupancy and covariates was strongest at the smaller spatial scales, though covariates at the larger spatial scales were still selected as relevant to occupancy. Our results highlight the importance for land managers to consider the landscape context prior to making on-the-ground conservation action; measures aimed to conserve grasslands, for example, will likely be ineffective if they take place in landscapes with high canopy cover.
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