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Physical Heterogeneity and Aquatic Community Function in River Networks
Citation:
Thoms, M., M. Delong, J. Flotemersch, AND S. Collins. Physical Heterogeneity and Aquatic Community Function in River Networks. Mississippi River Reserach Consortium, La Crosse, Wisconsin, April 26 - 28, 2017.
Impact/Purpose:
In previous research efforts, we delineated the functional process zones (FPZs) of the Kanawha River. In this study, we examined the relationship between the hydrogeomorphically-derived zones with food webs. We found a significant correlation which means we will be able to account for an increased amount of natural variability in systems when working to detect impacts from various anthropogenic activities.
Description:
The geomorphological character of a river network provides the template upon which evolution acts to create unique biological communities. Deciphering commonly observed patterns and processes within riverine landscapes resulting from the interplay between physical and biological components is a central tenet for the interdisciplinary field of river science. Relationships between the physical heterogeneity and food web character of functional process zones (FPZs) – large tracts of river with a similar geomorphic character - in the Kanawha River (West Virginia, USA) are examined in this study. Food web character was measured as food chain length (FCL), which reflects ecological community structure and ecosystem function. Our results show the same basal resources were present throughout the Kanawha River but their assimilation into the aquatic food web by primary consumers differed between FPZs. Differences in the trophic position of secondary consumers – fish - were also recorded between FPZs. Overall, both the morphological heterogeneity and heterogeneity of the river bed sediment of FPZs were significantly correlated with FCL. Specifically, FCL increases with greater FPZ physical heterogeneity, supporting tenet 8 of the river ecosystem synthesis.
