Mechanisms underlying nest predation near energy development: A test of the mesopredator release hypothesis Lindsey Sanders 2 and Anna Chalfoun 1,2 1 US Geological Survey; 2 Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming
Habitat alteration
Accelerated Natural Gas Production Kerr 2010
Wildlife and Energy Development Northrup and Wittemyer 2013
Shrubland birds are on the decline Knick et al 2003, Sauer et al 2013
Sauer et al 2013 Sagebrush-obligate songbirds = species of greatest conservation need W. Ammann Brewer s Sparrow J. Gallagher Sagebrush Sparrow Sage Thrasher J. McCarty
Nest Success with Habitat Loss Brewer s Sparrow 90% due to Predation Sagebrush Sparrow J. Gallagher Sage Thrasher J. McCarty Adapted from M. Gilbert thesis 2010
Nest Predator Identification Y. Krishnappa QK Eliminators Rodents = 80% of nest J. Spendelow predation events S. Creek D. Williams KJ Thurgood Discovery Planet C. Kurtzl Pixshark Hethcoat and Chalfoun 2015
WARNING: This footage is gruesome!!
Relative Abundance of Rodents Ground Squirrel Detections Deer Mouse Captures/ 100 Trap Nights Hethcoat and Chalfoun 2015
Mesopredator Release Crooks and Soule 1999
Is a mesopredator release driving rodent abundance near natural gas development? Apex Predator Detections Rodent Perceived Predation Risk
Study Area Pinedale Anticline Well Locations Upper Green River Basin, western Wyoming 2 natural gas fields: Pinedale Anticline and Jonah Field 5km Jonah Gas Field
Study Area Pinedale Anticline Well Locations Study Plots Upper Green River Basin, western Wyoming 2 natural gas fields: Pinedale Anticline and Jonah Field Sixteen 25-hectare study plots 5km Jonah Gas Field
Methods: Apex Predator Detections Trail Cameras Coyotes and badgers Point Counts Raptors
Predict: Decreased Apex Predator Detections Coyote Detections per Survey Badger Detections per Survey Raptor Detections per Survey
Result: Increased Apex Predator Detections Coyote Detections per Survey p = 0.194 χ 2 = 1.7 Badger Detections per Survey p < 0.001 χ 2 = 22.0 Raptor Detections per Survey p = 0.007 R 2 = 22%
Is a mesopredator release driving rodent abundance near natural gas development? Apex Predator Detections Rodent Perceived Predation Risk
Methods: Perceived Predation Risk Giving-Up Density (GUD) Experiment Safe tray Risky tray Charnov 1976, Brown 1988
Predict: Lower Perceived Predation Risk Safe tray Risky tray
Result: Higher Perceived Predation Risk Odds more seed eaten from safe foraging patch 4% Risky tray R 2 = 32% 95% CI = (1.002, 1.073)
Results Summary Sage Thrasher Daily Nest Survival (%) Deer Mouse Captures/ 100 Trap Nights Hethcoat and Chalfoun 2015
Results Summary Sage Thrasher Daily Nest Survival (%) Deer Mouse Captures/ 100 Trap Nights Badger Detections per Survey
Results Summary Sage Thrasher Daily Nest Survival (%) Deer Mouse Captures/ 100 Trap Nights Badger Detections per Survey Perceived Predation Risk
Is a mesopredator release driving rodent abundance near natural gas development? Apex Predator Rodent Perceived Detections Predation Risk NO NO
Future Research Directions Alternative hypotheses: food resource availability
Management Outcomes Mechanistic understanding important for targeted management and conservation Improve understanding of how processes with fitness consequences (predation) are altered by humans
Questions? Contact Info: sanders.lindsey@gmail.com Big Thanks to: The Chalfoun Lab Merav Ben-David Andrea Orabona Mark Thornoff Matthew Hethcoat Mandi Larson Mike Curran Tayler Scherr Tracey Johnson Ken Gerow Susan Patla Dale Woolwine Michelle GIlbert Sophie Miller Jay Norton Pete Guernsey