Climate and habitat interact to shape the thermal reaction norms of breeding phenology across lizard populations

Abstract

Substantial plastic variation in phenology in response to environmental heterogeneity through time in the same population has been uncovered in many species. However, our understanding of differences in reaction norms of phenology among populations from a given species remains limited. As the plasticity of phenological traits is often influenced by local thermal conditions, we expect local temperature to generate variation in the reaction norms between populations. Here, we explored temporal variation in parturition date across 11 populations of the common lizard (Zootoca vivipara) from four mountain chains as a function of air temperatures during mid-gestation. We characterized among-population variation to assess how local weather conditions (mean and variance of ambient temperatures during mid-gestation) and habitat openness (an index of anthropogenic disturbance) influence the thermal reaction norms of the parturition date. Our results provide evidence of interactive effects of anthropogenic disturbance and thermal conditions, with earlier parturition dates in warmer years on average especially in closed habitats. Variation in the reaction norms for parturition date was correlated with mean local thermal conditions at a broad geographical scale. However, populations exposed to variable thermal conditions had flatter thermal reaction norms. Assessing whether environmental heterogeneity drives differentiation among reaction norms is crucial to estimate the capacity of different populations to contend with projected climatic and anthropogenic challenges.

Phenology and the physiological niche are co‐adapted in a desert‐dwelling lizard

“…Performance advantages of offspring from early‐breeding females may arise from genetic or maternal effects, because eggs were separated between temperature treatments after oviposition. In lizards and other oviparous species, oviposition timing is heritable and repeatable (Ljungström et al, ; Rutschmann et al, ; Saastamoinen & Hanski, ; Visser et al, ). For example, larger females in sand lizards generally lay eggs earlier, and the butterflies that can fly at low temperatures generally initiate oviposition earlier (Ljungström et al, ; Saastamoinen & Hanski, ).…”

Reduction in baseline corticosterone secretion correlates with climate warming and drying across wild lizard populations

“…Indeed, high metabolism at rest and strong behavioural activity in warmer environments could induce diverse physiological costs such as higher energy expenditure, higher risk of dehydration and eventually negative impacts on survival and reproduction (Bestion et al., ; Dillon, Wang, & Huey, ; Huey et al., ; Kearney, Shine, & Porter, ; McKechnie & Wolf, ). Instead, the studied populations can associate micro‐adaptations (e.g., significant genetic differentiation among populations), different trajectory in life‐history strategies (Chamaillé‐Jammes et al., ; Dupoué, Rutschmann, Le Galliard, Clobert, et al., ; Rutschmann et al., ), which might explain some variations in corticosterone levels between populations. Besides, we must acknowledge that baseline corticosterone alone may not always correlate with individual stress and animal welfare (Otovic & Hutchinson, ).…”

The mechanisms of phenology: the patterns and processes of phenological shifts

“…Temperature response varies within and among species (Tauber and Tauber , Gunderson and Stillman , Rutschmann et al. ), and behavioral plasticity may buffer individuals from temperature change (Jones and Oldroyd ). Indeed, temperature‐change‐induced mortality in embryos (Levy et al.…”

“…While the relationship between temperature and ectotherm biology is strong (Kingsolver and Huey 2008), it is not simple. Temperature response varies within and among species (Tauber and Tauber 1976, Gunderson and Stillman 2015, Rutschmann et al 2016, and behavioral plasticity may buffer individuals from temperature change (Jones and Oldroyd 2006). Indeed, temperature-change-induced mortality in embryos (Levy et al 2015) or adults (Bestion et al 2015) could lead to phenological shifts that do not strictly track temperature; some propose global warming could create novel bivoltine breeding seasons in formerly univoltine species (Levy et al 2016).…”