Initial Response Of Birds To Shale Gas Development In A Forested Landscape

Open Access
Fronk, Nathan R
Graduate Program:
Wildlife and Fisheries Science
Master of Science
Document Type:
Master Thesis
Date of Defense:
August 26, 2013
Committee Members:
  • Margaret Brittingham, Thesis Advisor
  • Matthew Marshall, Thesis Advisor
  • William David Walter, Thesis Advisor
  • Marcellus shale
  • well pads
  • forest interior
  • synanthropic
  • core forest
Pennsylvania is currently experiencing rapid shale gas exploration, with the focus being on the Marcellus Shale play. Unlike the shallow gas extraction of western Pennsylvania, Marcellus shale development uses much greater quantities of land, water, and other resources. Marcellus shale development is concentrated in two areas within Pennsylvania, the north-central and south-west regions of the state. In the heavily forested north-central part of the state, forest habitat is being cleared and fragmented due to Marcellus shale exploration. North-central Pennsylvania holds the majority of core forest within Pennsylvania and many area-sensitive Neotropical migrant bird species depend on these forests for breeding habitat. Shale gas development in north-central Pennsylvania is of particular concern because of the importance of these forests to a variety of forest specialists. Marcellus shale gas development has created increased levels of fragmentation and edge habitat throughout the region through the creation of pipelines, well pads, and other Marcellus related infrastructure. In order to investigate the effects of Marcellus shale development on bird species, we used a Before-After Control-Impact study design using the newly completed 2nd Pennsylvania Breeding Bird Atlas (PBBA) as before data and as a sampling framework. During the PBBA (2004-2008) the state was divided into BBA blocks measuring ~2,500 hectares per block. Eight point count bird surveys were completed in each block to estimate bird abundance. During the 2011 and 2012 field seasons, points were resurveyed in 37 PBBA blocks, which served as the after data. Additionally, we compared current bird abundance with differing levels of Marcellus shale development at the BBA block (2488.9 ha) level. We created three species habitat guilds to aid in our analysis; synanthropic (or human-associated) species, early successional species, and forest interior species. The synanthropic species showed a significant positive response to Marcellus shale development in the Before-After Control-Impact (BACI) study and had a positive relationship with increasing levels of Marcellus shale development at the block level. The forest interior species guild exhibited a negative response to Marcellus shale development in the BACI analysis and had a weak negative relationship with increasing levels of well pads at the block level. The early successional species guild exhibited no relationship to Marcellus shale development. These results suggest that Marcellus shale development has caused changes in community structure. The initial response of birds to Marcellus development is an increase in human-associated or synanthropic species, which tend to be generalists, which can utilize newly created disturbances. Forest specialists have not shown extensive declines yet. This is most like due to the short time interval since shale development was initiated and the predominately forested landscape, which still persists. Declines in specialist species and an increase in generalist species will result in biotic homogenization throughout the region.