river modification, channelization, species richness, turtles, Iowa
Comparisons were made of turtle populations in Red Rock Reservoir and the major rivers of the Mississippi River and Missouri River damage systems in Iowa. Of the inland rivers of the Mississippi drainage examined in this study, the Des Moines River had the least amount of remaining turtle habitat. Number of turtle species ranged from five in the Des Moines River to 11 in the Mississippi River, but only three species were found in Red Rock Reservoir. In the Missouri drainage, number of turtle species ranged from three in both the Little Sioux and Nishnabotna rivers to five in the Missouri River. Regression analysis found remaining turtle habitat to be the strongest predictor of species richness. Stream modification appeared to lower the species richness of riverine turtles by eliminating intolerant species. Intolerant forms were absent when river modification eliminated their habitat and created a more uniform and simplified environment Map turtles (Graptemys geographica LeSueur), false map turtles (Graptemys pseudogeographica Gray), Blanding's turtles (Emydotdea blandingi Holbrook), and smooth soft-shells (Apalone mutica LeSueur), appeared to be most affected by modification. Turtle species richness was lower in Red Rock Reservoir than in the Des Moines River, possibly due to the great fluctuation in the water level of the reservoir.
Journal of the Iowa Academy of Science
© Copyright 1996 by the Iowa Academy of Science, Inc.
Vandewalle, Terry J. and Christiansen, James L.
"A Relationship Between River Modification and Species Richness of Freshwater Turtles in Iowa,"
The Journal of the Iowa Academy of Science: JIAS: Vol. 103:
, Article 3.
Available at: http://scholarworks.uni.edu/jias/vol103/iss1/3