Impacts of gas and oil development on sharp-tailed grouse (Tympanuchus phasianellus) nest success and predator dynamics in western North Dakota.

摘要

Recent advancements in extraction technologies are resulting in rapid increases of gas and oil development in western North Dakota. This expansion of energy development may have unknown effects on local wildlife populations and the ecological interactions within and among species. Sharp-tailed grouse (Tympanuchus phasianellus) are a popular upland game bird species that rely on grassland habitat found throughout the state. Potential impacts of gas and oil development on the nest success of sharp-tailed grouse is an area of particular interest as it is an important factor in avian reproduction. Similarly, it is equally important to understand the impacts experienced by the mammalian predator community as these species are the primary cause of sharp-tailed grouse nest failure. Our objectives for this study were to evaluate potential impacts on sharp-tailed grouse nest success and nest predator dynamics using two study sites that represented areas of high and low energy development intensities in western North Dakota. During the summers of 2012 and 2013, we monitored a total of 163 grouse nests using radio telemetry. Of these, 90 nests also were monitored using miniature cameras to accurately determine nest fates, estimate nest predator frequencies, and record various hen behaviors. We evaluated various nest site characteristics on daily nest survival using Program MARK. American badgers (Taxidea taxus) and striped skunks (Mephitis mephitis) were the primary nest predators, accounting for 56.7% of all video recorded nest depredations. Top models included predictors of study area and whether or not the nest was monitored with a camera. Nests in our high intensity gas and oil area were 1.95 times more likely to succeed compared to our minimal intensity area. Model average estimated daily nest survival was 0.975 (CI = 0.963-0.984) in the high intensity area, and 0.955 (CI = 0.937-0.967) in the low intensity area. Camera monitored nests were 2.03 times more likely to succeed than non-camera monitored nests. To evaluate the impacts of energy development on mammalian predators' use of the landscape, we simultaneously conducted predator surveys using camera scent stations during the summers of 2012 and 2013. We detected coyotes ( Canis latrans), striped skunks (Mephitis mephitis), red fox (Vulpes vulpes), American badgers (Taxidea taxus), and raccoons (Procyon lotor). We conducted occupancy analysis to evaluate differences in predator occurrence between study areas while incorporating various covariates associated with survey site characteristics and year in Program MARK. We found the mammalian predator community as a whole to be 4.5 times more likely to occur in our study area of minimal gas and oil intensity compared to the high intensity area, suggesting a negative relationship between energy development and predator occurrence. Although only a correlative study, our results suggest energy development may be negatively impacting the predator community, thereby increasing nest success for sharp-tailed grouse in areas of intense development while adjacent areas of minimal development may have increased predator occurrence and reduced grouse nest success. Thus, our study illustrates the potential influences of energy development on the nest predator prey dynamics of sharp-tailed grouse in western North Dakota and the complexity of evaluating these impacts on wildlife.