Morphology and demography of Sonoran mud turtles (Kinosternon sonoriense) along an aquatic habitat permanence gradient.

Abstract

Aquatic habitats exist along a permanence gradient and are characterized by the degree of interactions between abiotic (desiccation) and biotic (predation) factors, which are identified as characteristics that regulate body size and population demographics. Sonoran mud turtles (Kinosternon sonoriense ) occur in aquatic habitats that span the permanence gradient and are potentially impacted by environmental variables associated with these habitats. I sampled aquatic habitats in the Peloncillo Mountains (32°12'N, 108°60'W) and classified them as ephemeral, intermittent, or permanent. I investigated the influence of aquatic habitats on body size, population density, and juvenile recruitment of Sonoran mud turtles. Body size was significantly larger in turtles from permanent aquatic habitats. Juvenile recruitment was related to population density and was highest in intermittent aquatic habitats. These data reflect a distribution pattern that favors intermittent aquatic habitats with desiccation and predation limiting populations in ephemeral and permanent aquatic habitats, respectively. The Sonoran mud turtle is listed as a vulnerable species and my research identifies anthropogenic factors threatening habitat sustainability and population viability.