Diet and disturbance: Seaside Sparrow resource use driven by oiling and Hurricane Isaac

The 2010 Deepwater Horizon (DWH) disaster led to extensive oil deposition in Louisiana’s coastal wetlands, followed two years later by Hurricane Isaac. These disturbances changes saltmarsh invertebrate communities, potentially affecting higher-level predators and the food web. Seaside Sparrows ( Ammospiza maritima ) are ubiquitous, year-round residents of affected DWH spill, where they consume diverse invertebrates may be considered an indicator species for ecosystem’s integrity. We used DNA metabarcoding evaluate prey consumed understand how sparrows responded residual contamination from spill ecosystem disturbance caused To do so, we evaluated metrics diet (prey richness, diversity, overall composition) resource use (total niche width, individual specialization) 2011 2017 on oiled, unoiled, reference sites. found that while composition varied across site type, Isaac had even greater effect richness diversity consumed. Resource use—as measured total width populations degree specialization—was most stable unoiled sites compared Finally, analyzed each combination type year (i.e.: “2014 oiled sites”), which indicated a strong correlation between specialization width: as increased, individuals became more specialized, following predictions Niche Variation Hypothesis.