How influential are squamate reptile traits in explaining population responses to environmental disturbances

Abstract Context Understanding how organismal attributes influence sensitivity to environmental perturbations is a central theme in ecology and conservation. Certain traits, such as body size, habitat use, dietary preference and reproductive output are considered important determinants of animal species’ responses to the impacts of ecological disturbances. However, the general relationships between functional traits and post-disturbance responses by animals are not fully understood. Aims Our primary aim was to use a meta-analysis to evaluate the influence of species traits on variation in population abundances of squamate reptiles (i.e. lizards and snakes). Methods We extracted data from 107 original published studies, from which 1027 mean effect sizes of post-disturbance responses by 298 species were estimated. We examined short-term responses only (i.e. within 3 years since the most recent disturbance). A comprehensive range of disturbances was examined, such as habitat destruction, fragmentation, fire, and exotic-species invasions. We used Bayesian linear mixed-effect modelling (BLMM), utilising the Markov-chain Monte Carlo algorithm (MCMC) for the meta-regression. Specifically, we tested the influence of eight species traits (body size, diet, temporal activity pattern, sociality, reproductive mode, clutch size, habitat selection, and mean body temperature), along with disturbance type, in explaining variation in species-specific abundance responses of squamate reptiles post-disturbance. Key results Post-disturbance abundance responses of squamate species were significantly influenced by two parameters, namely, mean body temperature and clutch size. In general, significant positive responses post-disturbance were observed for species with higher mean body temperatures and a greater clutch size. The type of disturbance had no detectable influence on squamate abundances. The influence of random effects (heterogeneity among studies and species, and broad taxonomic identity) accounted for more of the model variation than did the fixed effects (species traits and disturbance type). Conclusions Certain species traits exerted some influence on the sensitivities of lizards and snakes to ecological disturbances, although the influence of random effects was very strong. Our findings are likely to be a result of the complexity and idiosyncratic nature of natural abundance patterns among animal species, in addition to the potential confounding effect of methodological differences among studies. Implications The present study is the first major quantitative synthesis of how species traits influence population-level responses of squamate reptiles to ecological disturbances. The findings can be used to guide conservation efforts and ecological management, such as by prioritising the efforts of mitigation on species that reproduce more slowly, and those with lower body temperatures.