Recent droughts have caused the loss of many perennial streams and associated riparian vegetation in Arizona. Riparian areas are important because they provide habitat and resources, such as food and water, to many different species of animals. Lizard communities may be negatively affected by this loss of perennial riparian habitats. As a first step toward understanding how lizards are affected by stream drying, we assessed microhabitat use and abundance of lizards along perennial (wet) and ephemeral (dry) streams in the Chiricahua Mountains. Our goal was to determine if microhabitat availability and use differs between three common species of lizards (Sceloporus jarrovi (Yarrow’s Spiny Lizard), Sceloporus virgatus (Striped Plateau Lizard), and Urosaurus ornatus (Ornate Tree Lizard) and how these factors differ between perennial and ephemeral streams. In June 2017, we established six 100 meter study transects, three along perennial streams and three along ephemeral streams. We mapped microhabitats (e.g shrubs, boulders, grass) in 5 x 5 meter plots along each transect. Finally, we executed a 21-day mark-recapture study along the six transects, marking individual lizards with a paint pen to help with identification. We also recorded the microhabitat type where each lizard was first sighted.
Results/Conclusions
Lizards had clear microhabitat preferences at our six study transects, and those preferences varied by species. For example, no lizards were found on grass, rock walls, or roads at the North Fork perennial site, despite those microhabitats being available to them. However, microhabitat use at the same site did vary by lizard species. One-hundred percent of S. jarrovii were found on small boulders, while U. ornatus preferred cobble (33% of individuals) and trees (67% of individuals). Our results also suggest that lizards use a greater variety of microhabitat types along perennial versus ephemeral streams. Lizards were found in five microhabitats types at the North Fork perennial site, but only four types at the paired ephemeral site. Similary, lizards were found in six different microhabitats at the South Fork perennial site, but only in four at the paired ephemeral site. Water and aquatic prey availability at perennial sites may facilitate expanded use of microhabitat types along perennial streams. We hope that the results of our research will provide insight into how stream drying may affect lizard communities.