ASSESSMENT OF A TURTLE COMMUNITY IN THE CEDAR RIVER, IOWA

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

We initiated a pilot project at Ingawanis Boy Scout Camp along the Cedar River 
(Bremer County, Iowa) to assess the river turtle community.  Wire turtle traps 
(Nichols Net & Twine Co., Inc., Granite City, Illinois) were opportunistically 
placed at a depth of no more than 1 m and baited with fat, gristle, and bone.  
Most trapping took place on weekends between late-May and early-September 2004.  
Significant flooding prevented trapping for several weeks throughout the summer.  
We recorded 47 captures of 46 individual turtles representing five species; 
spiny softshells (Apalone spinifera; n = 19), snapping turtles (Chelydra 
serpentina; n = 11), painted turtles (Chrysemys scripta; n = 12), common map 
turtles (Graptemys geographica; n = 2), and false map turtles (Graptemys 
pseudogeographica; n = 2).  All turtles were weighed, measured, and marked by 
drilling a binary code on the posterior scutes with a Dremel® tool.  Chelydra 
serpentina were the largest turtles captured, exceeding our capability to weigh 
them accurately; new equipment has since been purchased for use in the field 
during the next trapping effort.  Mean carapace length and mean carapace width 
was greater for Apalone spinifera than for Chrysemys scripta, but mean total 
mass was greater for Chrysemys scripta. Both Graptemys species were smaller in 
all measurements than the other species.  Graptemys pseudogeographica were 
larger than G. geographica.  We intend to continue and expand this project on 
river turtles to address issues of community-level and population-level change.


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