Hibernation habitat selection by the threatened Chinese softshell turtle (Pelodiscus sinensis) in the Yellow River wetlands of Northwest China: Implications for conservation management

Hibernation is a crucial aspect of the life history of freshwater turtles
inhabiting temperate regions. Therefore, understanding their hibernation
habitat selection is essential for the targeted conservation of turtle
species and their habitats. The Chinese softshell turtle (Pelodiscus
sinensis), a medium-sized freshwater turtle, is widely distributed in
China; however, populations are rapidly declining, threatened by habitat
destruction, overfishing, and water pollution. Little is known regarding
this species’ habitat selection during the winter months. In 2020–2022, we
equipped 22 P. sinensis with radio transmitters (VHF), and we successfully
relocated 13 turtles, 11 of which buried in submerged substrates and 2
buried in terrestrial soil for hibernation. In aquatic habitats, turtles
preferred ponded areas formed during the dry period of the Yellow River
with low water velocity and less anthropogenic disturbance. However, we
found little evidence for the selection of dissolved oxygen levels. In
terrestrial habitats, turtles buried under densely vegetated soils with
their dorsal carapace approximately 5 cm beneath the surface, allowing
respiration through a protruded neck. Terrestrial hibernacula were close
to the water, maintained more than 30% humidity throughout the winter, and
were effectively protected against freezing. To the best of our knowledge,
this is the first formal report of the behavior of terrestrial hibernation
in softshell turtles. Our results suggest that P. sinensis has selectivity
towards hibernation habitats with specific microenvironmental
characteristics, indicating that protection of the characterized habitats
provided in this study is important for the future conservation of this
threatened softshell turtle species.