Identifier

etd-11042015-125939

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

Louisiana’s small streams provide critical habitat for diverse ecologically and economically important fish species. However, the relationship between these fish assemblages and habitat variables remains poorly understood. The role of anthropogenic alteration of dendritic stream connectivity is of specific interest and has been shown to significantly influence stream ecology. This study explored the interaction among watershed characteristics, stream connectivity, stream physico-chemistry, and fish assemblages in little-studied Red River basin of central Louisiana as well as how reservoir littoral zones compared to streams, both in terms of fish assemblage and habitat. Fish and habitat were sampled in 21 headwater streams, half of which flowed directly into a reservoir, and in four reservoir littoral zone sites. Multivariate analyses indicated that level of dendritic connectivity did not explain a significant amount variation in stream fish assemblages. Fish assemblage composition and its relationship to common environmental gradients were similar in in all streams regardless of connectivity. Additionally, the assemblage and habitat of the reservoir littoral zone was comparable to that found in streams indicating that reservoirs were not serving as deleterious barriers to stream fish assemblages. However, individual species modeling revealed greater abundance of three species in streams with unaltered connectivity. These results do not parallel trends observed in other examinations of altered dendritic connectivity, however, they are concurrent with studies of coastal plain fishes’ response to other disturbances. Understanding the magnitude and structure of response to disturbance is critical for preserving aquatic ecosystems and focusing conservation efforts. Even systems such as the Red River Basin, which evidence strong resilience to human disturbance, warrant closer inspection before heedless system alteration continues.

Date

2015

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Kaller, Michael

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