Loss and fragmentation of grassland habitat can influence populations of the animal communities dependent upon this ecosystem. Grassland birds have faced notable declines in some areas of their range, potentially a result of changes to suitable habitat. Managing populations of grassland birds requires an understanding of the effects of habitat loss and fragmentation at a local and regional scale. We studied two grassland-dependent bird species, Eastern Meadowlarks (Sturnella magna) and Northern Bobwhites (Colinus virginianus), in an area of recent explosive growth in oil and gas related development. First, we quantified habitat lossand fragmentation of grassland habitat using remotely sensed datasets at multiple scales. We then assessed the effects of habitat loss and fragmentation resulting from oil and gas development and woody shrub encroachment via hierarchical distance sampling models of bird abundance. We found that meadowlark abundance was negatively related to woody shrub encroachment. The effect of oil and gas development varied from 2013 and 2015 – negative impacts in 2013 and neutral effects in 2015. Similar effects of oil and gas development were found with bobwhites, a negative effect in 2013 and no effect in 2015. The effects of woodycover also varied where it was a negative effect in 2013 and a positive quadratic relationship in 2015. Collectively, our results show that environmental perturbations – like drought (2013) and oil and gas development – cause variability in populations that are difficult to discern with short-term data. These results will help managers better understand how grassland birds respond to oil/gas development and the maps produced from our analyses will help prioritize areas for future conservation and improvement.
