Dissertations and Theses @ UNI


Thesis (UNI Access Only)


Redhorses--Habitat--Iowa; Redhorses--Conservation--Iowa; Black redhorse--Habitat--Iowa; Black redhorse--Conservation--Iowa;


The upper Mississippi is an interesting region because of its complex geological history and contemporary human impacts. These processes have influenced riverine ecosystems and dictated aquatic habitats. Landscape alteration and modification to waterways by human activity has resulted in contemporary changes to riverine habitats. These changes have imperiled numerous freshwater species in the region. One fish species listed as threatened and a species of greatest conservation need is the black redhorse, Moxostoma duquesnei. The goal of this study is to determine if specific habitat components are limiting black redhorse distribution and abundance in Iowa and if so are these components influenced by historical or contemporary process. This study examines the distributional extent, habitat associations, abundance, and genetic variation of the black redhorse in northeast Iowa. Prior to this study, information regarding black redhorse in Iowa was severely limited. Listing was predicated on the species restricted distribution and infrequent presence in fish assemblages. Ecological nice modeling revealed a relationship where black redhorse presence and distribution in the state is influenced by stream order and glacial landscape alterations. Analyses of habitat demonstrated a relationship between substrates and abundance. Estimates revealed that abundance was low among the rivers and streams of north central and northeastern Iowa but substantially higher in a transitional zone between two northeastern landform regions. Genetic analyses identified a uniform high genetic diversity across drainages. However, there was evidence of population substructure dividing the species into two distinct population clusters one of, which is largely confined and isolated. Based on what is known about other native fish species in the region and the life history of black redhorse the best explanation is that historical processes have largely dictated the species population dynamics in the state. However, the vulnerability of the species to changes in habitat is troubling where the landscape has been significantly altered by contemporary processes. The restricted distribution, potential for future habitat disturbance, and the isolation of a unique genetic cluster provide valuable data to substantiate the state threatened listing and guide future management actions.

Year of Submission


Degree Name

Master of Science


Environmental Science Program

First Advisor

Peter Berendzen, Chair

Date Original


Object Description

1 PDF file (ix, 128 pages)



File Format


Off-Campus Download