The Spring River, located within the Interior Highlands, supports one of the most biodiverse fish faunas (137 species) within Arkansas. However, threats to the fish communities include chronic pasture land-use and potential fish introductions from farm ponds within the watershed. These threats may degrade instream habitats, shift fish community composition to an alternative stable state, and cause biotic homogenization. Spring River fish collections during the 1970s were repeated at 31 sites using seines to examine fish community change over 40 years. This study aimed to address how pasture land-use may influence fish and stream conditions at multiple spatial scales. We also wanted to examine potential relationships between farm ponds and translocated species.
The Spring River watershed had the highest fish community persistence (mean = 0.69; range = 0.49-0.84) and stability (mean = 0.59; range = 0.46-0.75) when compared to several recent stream surveys within the Black River System. Community shift and biotic homogenization were detected at small catchments sites (< 500 km2) based on the results of a NMDS (PerMANOVA; p = 0.018) and a PCoA (PERMDISP; p = 0.007). Communities becoming more similar in composition were attributed to tolerant pool-dwelling fish and intolerant benthic fishes which have appeared to increase during the Contemporary period. Although many species expanded notably (> 20%) at sites between the two periods, only one species experienced a notable contraction. Arkansas Saddled Darter (Etheostoma euzonum) decreased at a substantial number of small catchments sites (-5) but remained stable at large catchments sites (> 500 km2).
Of the spatial scales examined, pasture at the two smallest scales (local buffer and 3 km upstream mainstem buffer) explained the most variation and was significantly associated with increasing number of tolerant species, number of tolerant species that expanded, % gravel at site, bank angle, and sorting index. The results of our study also demonstrated that farm ponds might contribute to homogenized fish communities. Number of farm ponds (1000 m radius) was positively associated with expanding number of tolerant species and expanding number of translocated species. Compared to other fish community studies with evidence of biotic homogenization, our system differs because of both tolerant and intolerant species additions. Our study is also the first to examine fish community change in the Spring River watershed, and among the first to demonstrate how farm ponds can influence fish communities.
|Advisor:||Adams, Ginny, Adams, Reid|
|Commitee:||Connolly, Matthew H., Quinn, Jeffery W.|
|School:||University of Central Arkansas|
|School Location:||United States -- Arkansas|
|Source:||MAI 82/8(E), Masters Abstracts International|
|Subjects:||Ecology, Geographic information science, Wildlife Conservation, Aquatic sciences, Limnology, Water Resources Management|
|Keywords:||Biotic homogenization, Historical repeat surveys, Multiscale land-use analysis, Native stream fish communities, Pasture land-use, Spatiotemporal dynamics, Spring River, Watershed|
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