Nest site selection and nesting behavior of the mud turtle Kinosternon scorpiodes (Testudines, Kinosternidae) in Palo Verde National Park, Costa Rica: implications for management

Abstract

Habitat selection is the process whereby individuals preferentially use, or occupy, a non-random set of available habitats. At the same time, nest site selection is defined as the placement of eggs by females at sites differing from random sites within a delimited area. We located 59 nests of the mud turtle Kinosternon scorpioides in Palo Verde National Park (PVNP) in Northwestern Costa Rica. We compared eight microhabitat variables at nest sites against those at random sites. Females significantly placed their eggs at sites with more understory, leaf litter cover, and greater leaf litter depth than in random sites. Additionally, females selected sites with lower air and soil temperature and lower air humidity. Palo Verde NP is subject to active management actions designed to control invasive plant species in the wetland, namely cattail (Thypha domingensis Pers.). The main actions have been cattle grazing, controlled fires, and mechanical crushing of vegetation. We found that habitat quality in nesting areas is being threatened by at least one of these actions: cattle grazing. This is detrimental for three microhabitat traits that turtles select for nesting sites: understory cover, leaf litter cover, and leaf litter depth. The continued degradation of microhabitats at nesting areas of K. scorpioides at PVNP could be affecting recruitment due to embryo survivorship.

Terrestrial movements, activity patterns and habitat use by Kinosternon scorpioides (Testudines: Kinosternidae) in Palo Verde National Park, Costa Rica

“…The core area needed to protect nesting, estivation and hibernation, and other terrestrial activities, varies by species (Steen et al 2012), but detailed data are essential to conservation. For example, to protect 100% of the K. scorpioides nests at PVNP, the core protected area would have to extend 175 m from t e et and b t protection of t e first m from the wetland would protect 86.4% of nests (Mora and Castañeda 2021). This observation about the use of terrestrial environments by K. scorpioides in PVNP illustrates how studies like the one reported here are necessary to ensure the future of species that are very often associated only with wetland habitats in the public view.…”