The Shape of Water: Physiological Adaptations to Habitat Aridity in the Ornate Tree Lizard (Urosaurus ornatus)

Abstract

Synopsis Deserts have always amazed researchers due to their high diversity of habitats, where plant and animal species have been able to adapt and diversify, even when these areas impose several constraints on an organism’s activity patterns. In particular, deserts support several lizard species adapted to the thermal and water restrictions found in such biomes. Although several studies have attempted to understand how lizard species might respond to water deficits or droughts in deserts, few have addressed how these responses might vary along a latitudinal gradient. This raises the question of whether physiological buffering of the organism or the climatic environment affects water loss in lizards. Here, we used six populations of Urosaurus ornatus to test whether water loss is influenced more by the intrinsic physiology of the lizard or by the climatic niche. We found that water loss is primarily influenced by the climatic niche of the lizard. However, future studies should focus on how microclimatic variables can influence water loss in organisms found across large latitudinal gradients.