A COMPARISON OF RIVER TURTLE COMMUNITIES AT TWO SITES ON 
THE CEDAR RIVER, IOWA

Valerie A. Kimler, Andrew J. Huck, and Gerald L. Zuercher
Department of Natural and Applied Sciences, University of Dubuque, 2000 University 
Avenue, Dubuque, IA 52001

In the absence of long-term monitoring, it is unclear whether spatial and temporal 
changes in river turtle community structure are due to environmental change or to 
exploitation by humans.  Although river turtle species richness may not differ between 
distant locations along a major watercourse, the composition of those communities often 
does differ.  Spatial differences may be reflective of different environmental conditions 
or may be due to different harvest pressure; only a few turtle species are currently 
protected from harvest in Iowa.  The Cedar River, Iowa represents an ideal test of spatial 
heterogeneity.  We compared river turtle communities at 2 sites on the Cedar River: 
Lower Cedar River (near Moscow, Iowa) and Upper Cedar River (near Waverly, Iowa).  
Species richness was identical for the 2 sites, but composition was different.  Turtle 
species captured from lower and upper reaches of the Cedar River were A. spinifera 
(spiny softshell turtle), Chelydra serpentina (snapping turtle), and Chrysemys picta 
(painted turtle).  At the Lower Cedar River site Graptemys ouachitensis (Ouachita map 
turtle) and Trachemys scripta (red-eared slider) also were captured while at the Upper 
Cedar River site Clemmys insculpta and G. pseudogeographica (false map turtle) were 
captured.  The capture of Clemmys insculpta is noteworthy due to its Endangered status 
that has been designated by Iowa Department of Natural Resources.  Multiple measures 
of community similarity suggest only moderate similarity between the 2 sites.  Measures 
of diversity were typically higher for the Lower Cedar River site.  Morphological 
comparisons (carapace length, carapace width, and total mass) of A. spinifera, Chelydra 
serpentina, and C. scripta between the Lower and Upper sites suggests differences occur 
within each species.

Keywords: Apalone spinifera, Cedar River, Chelydra serpentina, Chrysemys scripta, 
Iowa