Lori Pierce

Degree Name

Master of Science (MS)

Semester of Degree Completion


Thesis Director

Edward O. Moll


A community of six species of turtles from the Wabash River and its backwaters was studied to determine diet composition of each species and amount of dietary overlap among species. Species studied included: Trionyx muticus, Trionyx spiniferus, and Graptemys ouachitensis in the river; Trachemys scripta and Chrysemys picta in both the river and backwaters; and Chelydra serpentina in the backwaters only.

Trionyx muticus, T. spiniferus, and G. ouachitensis all belong to a guild that specializes on aquatic insects. The highest diet overlap (69.6%) was between the two softshells, T. muticus and T. spiniferus. Coexistence is possible because T. spiniferus are rare and there is some indication that they are feeding in different microhabitats, with T. spiniferus utilizing the bottom of the river and T. muticus feeding in the water column. Moderate overlap occurred between T. muticus and G. ouachitensis, but 58% of the diet differed.

Trachemys scripta are able to coexist with the other riverine species because they belong to a different guild. This species is highly herbivorous (93%) in the river, more so than in the sloughs (69%). Turtles occurring in the river had more diet overlap with T. scripta occurring in sloughs than with those in the riverine habitat. This could be due to niche partitioning in the river to reduce competition.

The remaining species encountered showed little diet overlap with any other turtle. Chelydra serpentina were piscivorous, while Chrysemys picta were omnivorous.

Turtle species of this community are able to coexist by feeding on different food items, foraging in different areas, and by occurring in small numbers.

Included in

Zoology Commons