Defense Date

9-7-2017

Graduation Date

Fall 1-1-2017

Availability

One-year Embargo

Submission Type

dissertation

Degree Name

PhD

Department

Biological Sciences

Committee Chair

Brady A. Porter

Committee Member

Jan E. Janecka

Committee Member

David J. Lampe

Committee Member

Steven C. Latta

Keywords

birds; diet; EPT taxa; macroinvertebrates; next-generation sequencing; resource subsidies

Abstract

Elucidating the diet of Neotropical migratory birds is essential to our understanding of their ecology and to their long-term conservation. Beyond broad taxonomic or morphological categories, however, the diet of Neotropical migrants is poorly documented. Using the molecular techniques of DNA barcoding and next-generation sequencing, we elucidated the diet of Neotropical migratory songbirds breeding in the riparian zones of headwater Appalachian streams. This approach resulted in a genus- or species-level description of diets that improved the current understanding of how songbirds utilize aquatic prey resources in riparian habitats. Furthermore, our approach revealed that breeding songbirds partition prey resources within a shared riparian habitat. Despite substantial differences in foraging strategy, we provide evidence that syntopic riparian species opportunistically prey upon pollution-sensitive emergent aquatic insects, thus emphasizing the importance of aquatic resource subsidies for songbirds breeding in riparian habitats. For the stream-dependent Louisiana Waterthrush, the provisioning of aquatic insects was significantly higher than other riparian songbirds. As a result, waterthrush breeding in riparian habitats with reduced availability of aquatic arthropods expanded their diet by targeting a more diverse array of insects that included significantly more terrestrial taxa. In addition to providing support for our hypothesis that Louisiana Waterthrush compensate for food shortages by targeting terrestrial arthropods in degraded riparian habitats, our findings emphasize the vulnerability of Louisiana Waterthrush to anthropogenic disturbances that compromise stream quality and the availability of pollution-sensitive aquatic insects.

Language

English

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