Brook trout distributional response to unconventional oil and gas development: Landscape context matters

• Published in: The Science of the total environment Vol. 628-629; pp. 338 - 349
• Main Authors: Merriam, Eric R., Petty, J. Todd, Maloney, Kelly O., Young, John A., Faulkner, Stephen P., Slonecker, E. Terrence, Milheim, Lesley E., Hailegiorgis, Atesmachew, Niles, Jonathan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2018
• Subjects: Animals; Cumulative impacts; Ecosystem; Environmental Monitoring; Habitat loss; Land use change; Marcellus shale; Oil and Gas Fields; Rivers; Salvelinus fontinalis; Species distribution modeling; Trout - physiology; Species distribution modeling; Salvelinus fontinalis; Marcellus shale; Cumulative impacts; Habitat loss; Land use change
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.02.062

•We assessed the role of landscape context in modulating brook trout response to UOG.•UOG impacted 11% of streams and resulted in a loss of predicted occupancy in 126.•Streams with a predicted loss of occupancy had intermediate non-UOG stress.•Model results were supported by pre- and post-UOG disturbance samples.•Effects of UOG are most relevant in streams with pre-existing habitat degradation. [Display omitted] We conducted a large-scale assessment of unconventional oil and gas (UOG) development effects on brook trout (Salvelinus fontinalis) distribution. We compiled 2231 brook trout collection records from the Upper Susquehanna River Watershed, USA. We used boosted regression tree (BRT) analysis to predict occurrence probability at the 1:24,000 stream-segment scale as a function of natural and anthropogenic landscape and climatic attributes. We then evaluated the importance of landscape context (i.e., pre-existing natural habitat quality and anthropogenic degradation) in modulating the effects of UOG on brook trout distribution under UOG development scenarios. BRT made use of 5 anthropogenic (28% relative influence) and 7 natural (72% relative influence) variables to model occurrence with a high degree of accuracy [Area Under the Receiver Operating Curve (AUC)=0.85 and cross-validated AUC=0.81]. UOG development impacted 11% (n=2784) of streams and resulted in a loss of predicted occurrence in 126 (4%). Most streams impacted by UOG had unsuitable underlying natural habitat quality (n=1220; 44%). Brook trout were predicted to be absent from an additional 26% (n=733) of streams due to pre-existing non-UOG land uses (i.e., agriculture, residential and commercial development, or historic mining). Streams with a predicted and observed (via existing pre- and post-disturbance fish sampling records) loss of occurrence due to UOG tended to have intermediate natural habitat quality and/or intermediate levels of non-UOG stress. Simulated development of permitted but undeveloped UOG wells (n=943) resulted in a loss of predicted occurrence in 27 additional streams. Loss of occurrence was strongly dependent upon landscape context, suggesting effects of current and future UOG development are likely most relevant in streams near the probability threshold due to pre-existing habitat degradation.