Meeting Abstract
Urbanization is occurring rapidly worldwide and is one of the greatest threats to biodiversity. How animals assess and respond to novel threats will likely predict who survives such rapid environmental change. In particular, human activity affects animal behavior and physiology (via the HPA axis), and individuals may need to modify responses to humans in order to co-exist with them in urbanized environments. We have categorized various lizard species in Southern California as urban intolerant, urban tolerant, or urban exploitive, and are quantifying behavioral and physiological fear responses to determine if anthropophobia (fear of humans) associates with intra- or interspecific differences in urban tolerance. Thus far, we have found that three species of nonnative lizard (urban exploiters) have higher escape responses from approaching humans and remain closer to refuge than native Western fence lizards (Sceloporus occidentalis), suggesting that an overall wariness of danger could promote establishment success in foreign habitats. Urban lizards also perceive humans differently based on clothing color, indicating that they are sensitive to nuanced aspects of human behavior. Across sites that vary in urbanization and human activity level, we find that the availability of good quality natural habitat promotes habituation to humans (reduction in fear responses), but lack of natural habitat could lead to sensitization and negative fitness effects. In addition to various behavioral measures, we are quantifying endocrine responses that could help maintain homeostasis in challenging environments.
