Spatial stream modeling of Louisiana Waterthrush (Parkesia motacilla) foraging substrate and aquatic prey in a watershed undergoing shale gas development

We demonstrate the use of spatial stream network models (SSNMs) to explore relationships between a semi-aquatic bioindicator songbird, Louisiana Waterthrush (Parkesia motacilla), and stream monitoring and benthic macroinvertebrate data in an area undergoing shale gas development. SSNMs allowed us to account for spatial autocorrelation inherent to these environmental data types and stream properties that traditional modeling approaches cannot capture to elucidate factors that affect waterthrush foraging locations. We monitored waterthrush along 58.1 km of 1st-and 2nd-order headwater stream tributaries (n = 14) in northwestern West Virginia over a two year period (2013-2014), sampled benthic macroinvertebrates in waterthrush territories, and collected wetted perimeter stream channel and water chemistry data along a 50 m fixed point stream grid. Spatial models outperformed traditional regression models and made a statistical difference in whether stream covariates of interest were considered relatable to waterthrush foraging. Waterthrush foraging probability index (FPI) was greater in areas where family and genus-level multi-metric indices of biotic stream integrity were higher (i.e. WVSCI and GLIMPSS). Waterthrush were found foraging both among stream flow connected and unconnected sampled sites on relatively further upstream locations where WVSCI and GLIMPSS were predicted to be highest. While there was no significant relationship found between FPI and shale gas land use on a catchment area scale, further information on waterthrush trophic dynamics and bioaccumulation of surface contaminants is needed before establishing the extent to which waterthrush foraging may be affected by shale gas development.

Automated summary

This study demonstrates the use of spatial stream network models (SSNMs) to explore the relationship between the Louisiana Waterthrush and stream monitoring and benthic macroinvertebrate data in an area undergoing shale gas development. The results show that SSNMs can effectively capture factors that affect the foraging locations of the waterthrush. The study found that the waterthrush foraged more in areas with higher biotic stream integrity. Additionally, there was no significant relationship found between the waterthrush foraging and shale gas land use in the catchment area, but further research is needed to determine the extent of the impact of shale gas development on waterthrush foraging.