Date of Graduation
Davis College of Agriculture, Natural Resources and Design
Wildlife and Fisheries Resources
The development of horizontal drilling for natural gas in the Marcellus Shale in 2004 resulted in rapid exploitation of the play in the Appalachian Basin. This “unconventional” gas well drilling accesses resources deeper beneath the surface and allows for multiple wells to be co-located on a single well pad. This results in fewer, but larger, well pads on the landscape than traditional vertical wells. Pipelines are required to transport the volumes of gas produced by unconventional wells to production facilities and market. The effects of gathering pipelines, which transport gas from well pads to larger transport pipelines, are poorly studied compared to other types of disturbance.
This study evaluated how ruffed grouse (Bonasa umbellus), salamanders and snakes, and pollinators use pipeline right-of-ways (ROW) in a forested environment. Forested areas of Appalachia have undergone forest maturation and young forest habitat has declined. This habitat modification led to declines of ruffed grouse and pollinator species. Although ROWs increase forest fragmentation in large forest patches, they must be maintained as herbaceous vegetation to protect pipeline integrity. The goals of this research were to determine how variation in ROW reclamation influences wildlife use of these ROWs. Difference in use can provide recommendations that enable ROWs to provide the most benefit to these species, and if they could act as an analogue for early successional habitat.
All research was conducted on the Tiadaghton State Forest and Game Commission Game Lands 12, two land parcels in North-Central Pennsylvania managed by the state. These areas are heavily forested and contain a network of natural gas ROW that varied in age, width, and reclamation. Surveys from ruffed grouse and pollinators were conducted on these sites from May –August 2019 and 2020. Cover boards used to sample for reptiles and amphibians were deployed in summer 2019 and surveyed from May — August 2020.
Too few ruffed grouse were observed during surveys to perform analysis, but incidental observations of white-tailed deer (Odocoileus virginianus) and eastern wild turkeys (Meleagris gallopavo) on ROWs suggests that they provide some benefits to these species. Eastern red backed salamanders (Plethodon cinereus) were used as a case study to examine the effects of the ROW on forest salamanders. Salamander occupancy increased as distance from the ROW edge increased, due to the negative effects of edge. Occupancy overall decreased as ROW age increased, and occupancy at all distances from the ROW edge decreased as ROW age increased. This suggests that edge effects degrade habitat along ROW over time, and that edge effects influence adjacent forest for at least 30m (farthest cover boards from the ROW edge). Snakes were observed on the ROW more than on the edge or in forest, and rodents were observed at most ROW sites. These suggest that snakes are more likely to utilize ROWs and that prey abundance is higher. Pollinators were more likely to be found at sites with higher percentages of flowering forbs. Butterfly species richness, butterfly density, and bee density were all positively related to the percent of flowers on the ROW. Pollinator density of each transect (10m ×100m) was not related to total ROW width, indicating that pollinator density is a function of flower abundance rather than an interaction between width and flower abundance. This suggests that pollinator abundance would increase as ROW width increases assuming flower percentage remains constant.
For the species in this study, ROW width negatively impacts forest salamanders but can be beneficial to snakes and pollinators. Differences in seed mix will change available food resources and vegetative structure. The best reclamation plan will vary based upon the circumstances and most imperiled species at each location. Overall, ROWs should be located along existing disturbance in forested areas to limit additional forest fragmentation. Reclamation should include seed mixes that prioritize native plants and maximize flowering throughout the growing season. The temporary workspace of each ROW should be replanted with fruiting trees and shrubs to increase forage for wildlife and soften the forest edge to reduce edge effects on salamanders. A ROW with these characteristics provides a balance between wildlife while providing resources which would otherwise be absent.
Knopka, Samuel C., "Unconventional Gas Pipeline Right-of-Way Influence on Wildlife" (2021). Graduate Theses, Dissertations, and Problem Reports. 8000.