Response of Louisiana Waterthrush to shale gas development
We examined effects of shale gas well and infrastructure development on Louisiana Waterthrush (Parkesia motacilla) at Lewis Wetzel Wildlife Management Area (WMA), WV. During 2009-2014, we quantified waterthrush nesting survival, territory density, and return rates on 57.9 km of headwater streams (n=12). We assessed vegetation immediately surrounding nests, and quantified a waterthrush Habitat Suitability Index (HSI) and the EPA Rapid Bioassessment protocol for in-stream characteristics important to aquatic macroinvertebrate prey. During 2013-2014, we quantified epigenetic (DNA methylation) differentiation of adults and nestlings in impacted versus unimpacted streams as an evolutionary adaptive response to a rapidly changing and potentially stressful environment. We then related the incidence of methylation in individuals to contaminant levels in feathers collected from those same individuals.
Early in the study (2009-2011) when little shale gas activity had occurred, we observed high annual return rates (57% in 2010, 61% in 2011) of 73 banded adults, territory density had minimal correlation with percent of stream impacted by shale gas development (2009: r2= 0.03; 2010: r2= 0.24; 2011 r2= 0.04), and nest survival within territories classed as impacted by shale gas development (43.2%; n=39) was similar to unimpacted territories (46.7%; n=84). However, the HSI and EPA indices were lower for nests in impacted territories suggesting that habitat quality had declined. Data from 2013 and 2014 are currently being analyzed. Overall trends across years suggest decreasing territory density and a decline in annual nest survival. We also noted increased parasitism rates of waterthrush nests since 2010 by Brown-headed Cowbirds (Molothrus ater); no parasitism occurred before 2010. Preliminary epigenetic results indicate that there is DNA methylation variation at specific DNA loci between individuals in unimpacted and impacted areas. Methylation also varies between adults and nestlings. Heavy metals associated with shale gas drilling appear to be correlated to the amount of methylation across loci. The presentation will summarize data for all aspects of the study from 2009-2014.