Effects of soil moisture on microhabitat selection of two fossorial amphisbaenian reptiles from contrasting environments

Climate conditions strongly influence variations in habitat characteristics, and, therefore, can mediate habitat selection. For example, increased extreme climatic events expected from climate change, such as extended drought periods or torrential rains, can alter soil conditions. However, the effects of climate fluctuations on fossorial vertebrates that inhabit subterranean environments, where soil characteristics play a fundamental role in their ecology and behaviour, remain insufficiently studied. In this study, we investigated microhabitat (substrate) selection in relation to soil moisture in two fossorial amphisbaenian reptile species from different environments: Blanus cinereus, from an Iberian continental temperate mountain forest, and Trogonophis wiegmanni, from a North African coastal warm and arid bushy area. In a laboratory experiment, we examined the preferences of the amphisbaenians for substrates manipulated with different moisture levels. We found that only B. cinereus showed a significant response, avoiding substrates with high moisture levels, while T. wiegmanni did not show a significant preference for any specific substrate moisture level. Our findings suggest that interspecific differences in responses to soil moisture may depend on environmental differences. While both species appear to show some tolerance to short-term drought periods, B. cinereus might be more sensitive to flood conditions resulting from torrential rains, suggesting higher vulnerability to climatic fluctuations. These results have important implications for understanding how climate change may affect the ecology and conservation of fossorial reptiles in different natural environments.