Ecological Responses to Hydrogeomorphic Fluctuations in a Sand Bed Prairie River: River Complexity, Habitat Availability, and Benthic Invertebrates

Abstract

Rivers with stochastic precipitation have fauna that overcome unique challenges. Organisms surmount these challenges by using refugia. Research was conducted on the sand bed Kansas River (Kaw). I (a) quantified how the hydrology affects the Kaw's shallow habitat complexity, (b) compared the amounts of hard vs. sand substrates, and (c) related abiotic variables to the community composition of benthic macroinvertebrates. I developed the riverscape complexity ratio, a metric that measures all types of river structures, found there was little hard substrate for zoobenthos to colonize, and that the zoobenthos had different communities at different river complexity levels. Zoobenthos in the Kaw use the river structures as refuges from flow spikes that eliminate species in the main channel. Unfortunately, flood control structures have eliminated much of the complexity in the Kaw. These habitats must be preserved since much of the food web uses these structures as vital nursery and feeding habitats.