Terrestrial habitat use by pacific pond turtles in a Mediterranean climate

The Pacific pond turtle (Clemmys marmorata) is a widespread aquatic turtle in the Pacific states, yet relatively little is known about its ecology. We radio-tracked 34 individuals during an 8 year period in 4 small coastal creeks in central California to determine their use of terrestrial upland habitats. Most of our turtles left the drying arroyos during late summer and returned after winter floods. Turtles spent an average of 111 days at these land refuges, which were located in woodland and coastal sage scrub habitats an average of 50 m from arroyos. Most gravid females left the creeks during June to oviposit in sunny upland habitats with low vegetation structure, such as grazed pastures. Nest sites were an average of 28 m from creeks. Terrestrial basking sites averaged 4.5 m from streams, but were only used for a few days. We believe the use of terrestrial upland sites was related to the Mediterranean climate and the resulting unique hydrodynamics of the small coastal arroyos (dry in summer and flooding in winter).