Historic and Current Composition of Lizard Communities in Urban Preserves of Central Arizona, USA

Urbanization is rapidly enveloping isolated remnants of Sonoran Desert habitat in southern Arizona. Understanding the means by which herpetofaunal elements can persist in these habitats in the face of multiple impacts is vital to conservation efforts to retain intact biotic communities, especially those with a high diversity of reptile species. We surveyed twelve preserves in the Phoenix Metropolitan region, five of which had been surveyed decades earlier, and obtained estimates of the diversity (species richness) and relative abundance of lizards. In comparison to surveys of the same preserves 20 to 40 years prior, one lizard species is absent from one large preserve where it was once present, but communities are otherwise largely similar in diversity and abundance over the past few decades. Larger preserves have higher diversity but not higher abundance of lizards. The range in diversity indices (i.e., species richness and evenness) across preserves we documented encompasses the range in diversity indices derived from other studies of urban lizard communities in the Southwest. Individual variation in distribution and abundance of component species must be investigated to adequately assess declines at the community level. We lack historically detailed data on distribution of many lizards and snakes, preventing an accurate analysis of species loss over the past 50 years.