Terrestrial vertebrates in Pennsylvania: Status and conservation in a changing landscape

In this paper, I review major historical conservation events, changes in landscape (cover types) patterns, and agency (state and federal) inventory and monitoring programs to help explain trends in terrestrial vertebrate populations in Pennsylvania. I then give recommendations for the long-term conservation of terrestrial vertebrates within the context of a future changing landscape in the Commonwealth. In Pennsylvania, the amount of forest has remained relatively constant since the 1970s, while the extent of early successional, grassland, and wetland/riparian habitats is declining. These trends, combined with direct human disturbance, degradation of water quality, and loss of critical habitat features have contributed to the endangered or threatened status of 31 vertebrate species in the state. Based on two major databases, the Pennsylvania Breeding Bird Survey and the Pennsylvania Breeding Bird Atlas, bird species occupying early successional, grassland, or wetland/riparian habitats, in particular, have generally shown negative trends in abundance and distribution, respectively. According to the Pennsylvania Gap Analysis Project, highest species richness or "hotspots" of mammals and birds are in areas with expanses of intact forest, as on public lands in the north central part of the state. The future conservation status of terrestrial vertebrates is contingent on several factors, ranging from wise stewardship of public and private lands to an understanding of the impacts of global climate change on vertebrate populations. Among the conservation recommendations are the need to improve connectivity among wildlands, understand the long-term impact of landscape changes on wildlife biodiversity, and develop databases on abundance and distributional trends of terrestrial vertebrate populations.