Fish Community Assembly in the Missouri River Basin

Warmwater fish communities of the Missouri River basin are poorly studied. I conducted a series of investigations intended to explain fish community structure and composition therein. I focused on relations between environmental characteristics and fish species because abiotic factors are considered most important for stream fish community dynamics, particularly within harsh streams, such as those of the Missouri River basin. I began with a study of broad scale patterns among western tributary drainages of the Missouri River. I took an island biogeography approach and tested to determine whether tributaries were insular in the sense that tributary drainage area and isolation from the source of colonists could account for native species richness and composition. I focused on western tributaries (i.e., those within the Great Plains geomorphic province) to control for major differences in hydrology and geomorphology. Eastern Missouri River tributaries of the Central Lowlands or Ozark Plateaus provinces are physically different from those of the Great Plains and such differences would certainly confound an island biogeography study. Findings showed that both tributary drainage area and isolation were important for determining fish species richness and composition among western Missouri River tributary basins. They also showed that fish faunal similarity among tributary drainages corresponded closely to geography. These findings were expected because there is a strong environmental gradient of increasing cold from downstream to upstream along the Missouri River, which, along with distance, presumably explains the importance of tributary basin isolation to fish community structure. The importance of tributary drainage area likely is due to the presence of a wider range of habitats within larger tributary drainages and the ability of larger drainages to support larger populations of each species. As a result, dramatic climate fluctuations that have typified the Great Plains for 2.8 million years cause more fish species extirpations from smaller tributary drainages, while more species persist in larger tributary drainages. My second study analyzed fish faunal patterns among river drainages of South Dakota. I analyzed zoogeographic patterns throughout the state for both historic (all natives) and recent (post-1990) faunas. I also assessed faunal change from historic to recent times. Findings indicated that historic and recent river drainage faunas differed dramatically between the Great Plains and Central Lowlands geomorphic provinces. In addition, there was high faunal disparity (beta diversity) between neighboring river drainages. The river drainages of South Dakota compose a “riverine archipelago” where every drainage has a distinct fish fauna, similar to a chain of islands. The recent fish fauna of South Dakota was dramatically different from the historical fauna with several species being absent from the state or from certain river drainages, other species having expanded distributions, and several species being introduced to the state. The Great Plains and Central Lowlands fish faunas were substantially homogenized because several native species that were historically restricted to the Central Lowlands disappeared, while other species that were historically restricted to the Central Lowlands became established within the Great Plains. A lower level of faunal homogenization was detected statewide among all river drainages, again indicating that some native species with restricted distributions have declined while others have expanded. As a group, species that were introduced to South Dakota did not contribute to homogenization because they had limited distributions. However, their continued spread could increase homogenization in the future, particularly if native species with restricted distributions continue to decline. My third study assessed relations between river size and fish assemblage structure and composition. This study was focused on the four major rivers of southwestern South Dakota because four previous studies provided comparable data on fish assemblages and river size along each river. In addition, U. S. Geological Survey gage and National Elevation Database data provided alternative measures of river size and gage data were also useful to assess discharge flashiness (environmental harshness). All four rivers increased substantially in size from upstream to downstream but, in contrast to typical rivers, discharge flashiness did not decrease as river size increased. Fish species diversity remained similar along each river, suggesting that high discharge flashiness may limit species diversity. Fish species composition was variable along the Bad River, presumably because habitat conditions changed from the headwaters to the river mouth. Fish species composition was variable along the Belle Fourche and Cheyenne rivers in association with dams. Dams appeared to favor small river fishes and impact large river fishes. In contrast, fish species composition was relatively similar along the undammed White River, suggesting that large river fishes would have been widespread in the much larger Belle Fourche and Cheyenne rivers prior to dam construction. Overall, fish faunal structure was less variable than fish faunal composition, suggesting that local habitat features may determine fish assemblage composition while large-scale environmental features, such as discharge flashiness, must determine fish species diversity. My fourth study examined fish assemblage structure (diversity, species abundance distributions) and composition among five streams within the Cheyenne River watershed of South Dakota.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation - University Access Only

Discipline thesis:degree_discipline

Wildlife and Fisheries Science

Year

2006

Author dc:creator

• Hoagstrom, Christopher W.

Contributors dc:contributor

• Charles R. Berry Jr.

• fish communities
• missouri river
• basin
• environment
• Natural Resources and Conservation

Statement dc:rights

• Copyright © 2006 Chris W. Hoagstrom. All rights reserved.

Language dc:language

en

Repository record dc:identifier

https://openprairie.sdstate.edu/etd/471

OAI identifier oai:identifier

oai:openprairie.sdstate.edu:etd-1471