Influence of exurban development on bird species richness and diversity

Exurban development is an accelerating land use trend in the United States with new housing units emerging in formerly closed forests. Conservation practitioners and planners suspect exurban development alters ecological processes and biodiversity to a considerable larger extent than suspected by inhabitants of exurban development areas, but empirical support for this assertion is lacking. To examine the consequences of exurban development, we studied forest bird communities in exurban development and forests located in and around Shenandoah National Park and Massanutten Mountain in northern Virginia, USA. We conducted point-count surveys for birds three times at 106 sample locations from April to July 2006. We recorded 44 species in total; 30 species were present in both exurban development and forests, 9 species were only found in exurban development, and 5 species only in forest. Bird species composition differed significantly between land-use types based on analysis in a multi-response permutation procedure (MRPP; P < 0.01). Relative bird abundance for forest specialist species changed significantly in exurban development versus forest (t test, P < 0.05). Three species, American Robin Turdus migratorius, Northern Cardinal Cardinalis cardinalis, and Common Grackle Quiscalus quiscula were indicators of exurban development. Indicators of forest were Carolina Chickadee Poecile carolinensis, Eastern Towhee Pipilo erythrophthalmus, and Wood Thrush Hylocichla mustelina. Our study demonstrates that exurban development alters bird community composition and relative abundance of forest specialist species.