Date of Award

Summer 7-5-2023

Document Type

Thesis

Degree Name

Master of Science in Fisheries and Wildlife Science

Committee Chair

Susan Colvin

Second Committee Member

John Jackson

Third Committee Member

Dustin Lynch

Fourth Committee Member

Darrell Bowman

Program Director

Tom Nupp

Dean of Graduate College

Sarah Gordon

Abstract

The karst region of NW Arkansas is home to many headwater endemic Species of Greatest Conservation Need (SGCN). This includes many species of darters, such as Etheostoma cragini, E. microperca, and E. mihileze, as well as crayfish such as Faxonious meeki brevis and F. nana. NW Arkansas is rapidly urbanizing, increasing the need to construct structures like culverts, bridges, and fords. These man-made road crossings can cause stream habitat degradation and fragmentation, as well as impair overall stream connectivity. To evaluate the impact that road crossings have on aquatic SGCN species and their habitat, 30 headwater streams were sampled throughout Benton and Washington counties. A series of Wilcoxon signed-rank tests were used to examine relationships between road crossing presence and stream habitat. Stream sites with road crossings had significantly higher water temperatures and conductivity, as well as more embedded substrates and increased levels of bank incision. Partial least squares regression was used to examine how road crossing presence and stream habitat variables influence SGCN abundance, density, condition, diversity indices, and community metrics. The composition of fine sediment and aquatic vegetation, which is preferred habitat for E. cragini and E. microperca, was significantly lower at sites with road crossings. SGCN darters tended to occur less frequently at sites with these structures, and at smaller abundances when they did occur. However, SGCN crayfish occurred at higher abundances at sites with road crossings, which typically had larger substrates. Additionally, the condition of F. nana, along with two other non-SGCN species, was significantly higher when these structures were present. These data suggest the need for multispecies conservation approaches, as road crossings may affect SGCNs uniquely, especially across taxonomic groups.

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