Figure 5
From: Plasticity in nest site choice behavior in response to hydric conditions in a reptile
Relationships between soil moisture (top) and soil temperatures (bottom) with depth for ground-nesting reptiles, based on data taken from V. panoptes nesting warrens39,46. Most ground-nesting reptiles nest between 2–30 cm deep, where there is often a strong inverse relationship between soil moisture and both mean and daily range in soil temperatures. A few larger species (e.g., iguanas, sea turtles) deposit nests at depths of up to 1 m, but only deep-nesting monitor lizards nest 1–4 m deep, and in these nests moisture and temperature (both mean and daily range) become uncoupled because the change in temperatures with depth through 1–4 m is negligible. There are two caveats here: (1) a rainfall event can temporarily reverse the soil moisture-depth gradient shown; and (2) the mean temperature-depth gradient shown is restricted to seasons in which mean air temperature is generally higher than mean soil temperature when considering depths > 1 m (i.e., during spring and summer).
