Temporal and spatial variation in the long-term functional organization of fish assemblages in a large river
- 182 Downloads
We examined abundances of fishes by ecological categories for variation with time (years) and longitudinal river distance (km) in the Wabash River, a large US Midwestern river. An ordination resulted in significant correlations with time for an axis that represented increases in surface-feeding invertivores and species that prefer sand substrates. We found increased abundances of planktivores and species with high tolerance to silt in downstream river sites. We found significant changes in abundance for the majority of ecological categories in comparisons of upstream–downstream locations. There was a general decrease in abundances of taxa in ecological categories that tend to inhabit upstream reaches: species that prefer rubble substrates, inhabit fast, and moderate current velocity habitats, and that have low silt tolerance with time. These abundance changes suggest that the upstream river experienced increased sedimentation during 1974–1998. The use of ecological categories provided information for likely habitat changes, such as increased sedimentation, that were not apparent in previous taxonomic analyses. We suggest that combinations of anthropogenic impacts including hydrologic alterations and agricultural activities in the Wabash River resulted in ecosystem changes and subsequent changes in abundance of fishes by ecological categories.
KeywordsFish assemblages Large river Community ecology
We are grateful to James Gammon for data.
- Benjamini, Y. & Y. Hochberg, 1995. Controlling the false discovery rate: a practical and powerful approach to multiple testing. Journal of the Royal Statistics Society: Series B 57: 289–300.Google Scholar
- Benke, A. C. & C. E. Cushing, 2005. Rivers of North America. Elsevier Academic Press, Burlington, MA.Google Scholar
- Gammon, J. R., 1998. The Wabash River Ecosystem. Indiana University Press, Bloomington, IN.Google Scholar
- Irons, K. S., G. G. Sass, M. A. McClelland & J. D. Stafford, 2007. Reduced condition factor of two native fish species coincident with invasion of non-native Asian carps in the Illinois River, U.S.A. Is this evidence for competition and reduced fitness? Journal of Fish Biology 71(Suppl D): 258–273.CrossRefGoogle Scholar
- McCune, B. & J. B. Grace, 2002. Analysis of Ecological Communities. MjM Software Design, Gleneden Beach, OR.Google Scholar
- McCune, B. & M. J. Mefford, 1999. PC-ORD. Multivariate Analysis of Ecological Data. Version 4.20. MjM Software, Gleneden Beach, OR.Google Scholar
- Pyron, M., C. C. Vaughn, M. R. Winston & J. Pigg, 1998. Fish assemblage structure from 20 years of collections in the Kiamichi River, Oklahoma. Southwestern Naturalist 43: 336–343.Google Scholar