The relative effects of habitat amount, habitat configuration, and urbanization intensity on forest breeding birds

It is clear that urbanization causes changes in landscape structure that adversely affect biodiversity. However, the relative impacts of different components of landscape structure remain unclear. Using the 2006 National Land Cover Database and 2010 U.S. Census data, I quantified habitat amount, habitat configuration, and matrix quality in concentric landscapes of ten different radii (ranging from 0.2km to 16km) centered on forested point counts spanning the state of Pennsylvania in order to distinguish the independent impacts of these three aspects of landscape structure. I estimated forest bird abundance, species richness, species evenness, and American robin and Scarlet tanager occurrence from a large and spatially-extensive dataset of point counts collected during the 2nd Pennsylvania Breeding Bird Atlas conducted 2004-2009. I used generalized linear modeling and a multi-model inference approach to determine the relative effects of these three aspects of landscape structure in Pennsylvania landscapes on avian biodiversity in remnant forest. Of the three elements of landscape structure investigated, matrix quality was the most influential predictor of diversity and species occurrence. This research suggests that modifications to the urban and agricultural matrix surrounding forest patches will have more influence on forest birds than attempts to alter forest amount or configuration. These results are expected to be of particular interest to land managers given the emergent intensity of the Marcellus shale gas industry and its impacts on landscape structure in Pennsylvania landscapes.