Prioritizing aquatic conservation areas using spatial patterns and partitioning of fish community diversity in a near-natural temperate basin
S. B. Cook, Department of Biology, Tennessee Technological University, Box 5063, 1100 North Dixie Avenue, Cookeville, TN 38505, USA. E-mail: SBCook@tntech.edu
- This study investigated spatial patterns and partitioning of fish community diversity in the Emory River basin, Tennessee, USA, which represents the best available biotic condition in a region characterized with high diversity and endemism. Fish community analyses were intended as one criterion for identifying aquatic conservation areas in a Habitat Conservation Plan (HCP) currently developed in the study region under the authority of the US Endangered Species Act.
- Spatial patterns of fish community diversity were examined at 57 stream sites located in the mainstem (13 sites) and four sub-basins (a total of 44 sites) by partitioning γ diversity (total diversity) into α (within-community) and β (among-community) components in a multiplicative manner at two spatial scales. Additional analyses were conducted to assess evidence of dispersal in structuring local communities.
- Mainstem sites were characterized with higher α diversity values relative to sub-basin sites, and γ diversity of 13 mainstem sites was comparable with that of 44 sub-basin sites. Site-level β diversity differed among sub-basins. Among-sub-basin β diversity was only modest, and one sub-basin harboured the majority of total species richness found among all sub-basins.
- Many species had high indicator values for mainstem sites, but sub-basin sites were associated with few indicator species. Spatial autcorrelation of fish community similarity was significant within mainstem sites and sites located within two sub-basins. Catchment area explained among-site variation in species richness better than stream order, link magnitude, confluence link or downstream link. Overall, there was a lack of evidence that dispersal played an important role in shaping local fish communities in either mainstem or sub-basin sites.
- Aquatic conservation in the study basin should focus on protecting aquatic diversity in the mainstem habitat, while a network of stream sites in the most diverse sub-basin may also be considered as aquatic conservation areas. Copyright © 2012 John Wiley & Sons, Ltd.