Dietary Niche of Three Omnivorous Turtle Species in a Northern Florida River: Insights from Stable Isotope Analysis

Abstract

Macrochelys suwanniensis (Suwannee Alligator Snapping Turtle) coexists with 2 other native large omnivorous turtle species (Chelydra serpentina [Snapping Turtle] and Trachemys scripta scripta [Yellow-bellied Slider]) in a 9-km section of the Santa Fe River in northern Florida. A major shift in dominant submersed aquatic vegetation prompted us to quantify trophic position and niche overlap among these 3 species. Here, we examine carbon and nitrogen isotopic values of these turtles and their potential food resources within the changing riverine system. We provide evidence of low isotopic niche overlap between M. suwanniensis and C. serpentina, whereas T. s. scripta occupied a discrete niche having lower carbon and nitrogen values.

Bite-Force Scaling across Size Classes in the Alligator Snapping Turtle (Macrochelys temminckii) and the Common Snapping Turtle (Chelydra serpentina)

“…Size is a significant factor when comparing Alligator Snapping Turtles and Common Snapping Turtles because Alligator Snapping Turtles are the largest freshwater turtles in North America and have disproportionately larger heads than Common Snapping Turtles (Ernst and Lovich 2009). Although morphological differences between Macrochelys and Chelydra likely induce interspecific differences in diet, these turtles have similar prey bases, including in areas where they coexist (Denton et al 2023 [this issue], East and Ligon 2013, East et al 2013, Elsey 2006, Johnston et al 2015, Pritchard 2006, Punzo 1975). .…”