Data from: Local climate and forest cover drive geographic variation of functional and reproductive traits in a viviparous lizard

Ecological impacts of climate warming in ectotherms can manifest across various biological levels with heat stress disrupting cellular processes, functional traits and life-history strategies. Using space-for-time substitutions where one examines geographic variation in population phenotypes allows to make predictions for biotic responses to climate warming over time. Yet, this approach requires a multivariate description of the local environment to infer a potential causal relationship between climate conditions and phenotypes. Here, we examined the geographical variation in cellular, morphological, physiological, behavioural and reproductive traits of adult female common lizards (Zootoca vivipara) across 14 natural populations along an environmental gradient with contrasting daytime and nighttime temperatures, forest cover and free-standing water access. We found significant geographical variations in all female traits, except resting metabolic rates. Geographic trait variation was mainly correlated with local thermal conditions and forest cover, but not with access to free-standing water. Females from populations with warm nighttime temperatures had lower total evaporative water losses, while females from populations exposed to higher daytime temperatures had lower preferred body temperatures. Females from populations with higher forest cover had a higher body condition at capture and an earlier emergence time. In addition, female telomere length (a biological marker of ageing) was higher in populations with lower temperatures and a high forest cover. Reproductive traits were mainly determined by the forest cover and to a lesser extent by nighttime local temperature. Females from populations with high forest cover had delayed parturition dates, higher reproductive investment and a higher post-partum condition. However, the number of viable juveniles at birth was negatively correlated with high local nighttime temperatures. Our integrative study suggests that local diurnal and nocturnal thermal conditions as well as forest cover can lead to changes in cellular, physiological, behavioural and reproductive traits. While thermal stress and habitat alteration are growing threats to terrestrial ectotherms, taking into account intraspecific variations in functional and reproductive traits together with changes in diurnal, nocturnal temperatures and vegetation will be essential for predicting ectotherms responses to current and future climates.