Bird community response to Marcellus shale gas development

The Appalachian shale play, which includes the Marcellus shale formation, is an important source of natural gas and underlies much of the remaining large areas of extensive contiguous forest within the eastern United States, areas that are important breeding sites for forest songbirds. Shale gas development in contiguous forest creates large disturbances and causes habitat fragmentation; the landscape matrix remains characterized by stands of mature forest. We assessed the effects of shale gas development on counts of passerines and near-passerine birds within an extensively forested landscape. We surveyed birds within 2 broad forest types (northern hardwood and mixed oak) at increasing distances from 49 shale gas pads established within contiguous forest habitat. We compared counts of individual species and 3 vegetation-association groups (forest interior, synanthropic, and early successional) in relation to distance from a pad edge, and we compared community composition with distance from a pad edge. Counts of individuals and species within the forest interior group increased with increasing distance from a pad edge; counts of individuals were approximately 4 times greater at 250 m than at 0 m and 3 times greater than at 50 m. Twelve of 15 species in the forest interior group increased with increasing distance from a pad edge with no species showing a declining trend. In contrast, counts of synanthropic (i.e., human-associated) individuals and species were greatest at the pad edge and declined with distance to a pad edge. Counts of individuals at 250 m were 92% lower than at 0 m, and counts for 4 of the 5 individual species declined with increasing distance from a pad edge. Counts of individuals and species within the early successional habitat group were greater in oak (Quercus spp.) than in northern hardwood forests, and the response to a pad edge differed among species and between the 2 forest types. In northern hardwood stands, counts were greatest near the pad edge, whereas counts in oak stands showed no trend with distance to a pad edge. Overall, the combined avian community differed with distance from a pad edge. Our results suggest that synanthropic species, which are rare in core forest, are able to rapidly exploit new development-associated habitat. Counts of forest interior specialists declined, suggesting the habitat is becoming less suitable for this group. Our results are an early indication that shale gas development in core forest can hav