Fracking, which mines natural gas using horizontal, hydraulically fractured wells, is widespread across Pennsylvania, with high-volume horizontal hydraulic fracturing (HVHHF) from the Marcellus and Utica shales covering up to 280,000 km² of the Appalachian Basin. 

A new paper in the Annals of the New York Academy of Sciences by Dr.Erik Kiviat, of the Hudsonia ecology group, says that natural gas wells are a threat to biodiversity, including pollution from toxic chemicals, the building of well pads and pipelines, and changes to wetlands.

Kiviat cites physical and chemical impacts of fracking, including pollution by toxic synthetic chemicals, salt, and radionuclides, landscape fragmentation by wellpads, pipelines, and roads, alteration of stream and wetland hydrology, and increased truck traffic. He says that there has been little study of the impacts on habitats and biota. Taxa and guilds potentially sensitive to HVHHF impacts include freshwater organisms (e.g., brook trout, freshwater mussels), fragmentation-sensitive biota (e.g., forest-interior breeding birds, forest orchids), and species with restricted geographic ranges (e.g., Wehrle's salamander, tongue-tied minnow).

"Shale gas has engendered a great deal of controversy, largely because of its impact on human health, but effects on biological diversity and resources have scarcely been addressed in the public debate," said study author and ecologist Erik Kiviat. "This study indicated a wide range of potential impacts, some of which could be severe, including salinization of soils and surface waters and fragmentation of forests. The degree of industrialization of shale gas landscapes, and the 285,000 km² extent of the Marcellus and Utica shale gas region alone, should require great caution regarding impacts on biodiversity."

Citation: Erik Kiviat, 'Risks to biodiversity from hydraulic fracturing for natural gas in the Marcellus and Utica shales', Annals of the New York Academy of Sciences, Volume 1286, The Year in Ecology and Conservation Biology pages 1–14, May 2013 DOI: 10.1111/nyas.12146