Various responses of pine marten morphology and demography to temporal climate changes and primary productivity

Climate and environmental changes affect species' morphology and ecology, with different responses to shifting abiotic and biotic factors observed across species. Here, we tested how the structural body size of the pine marten and its population sex ratio shifted over time alongside climate change. We analysed temporal changes in morphological traits using 11 measurements of pine marten skulls (N = 158) collected between 1903 and 2020 and originating from Poland. We linked them with climatic and primary production variations and assessed demographic shifts by calculating temporal sex ratio changes over 61 years (N = 205). Skull size, as a proxy of body size, increased in response to warmer and less snowy winters. However, changes in primary productivity rapidly shaped postorbital constriction regardless of shifts in body size, potentially demonstrating increased diet diversity in pine marten. Congruent with climate change, the population sex ratio has skewed towards males over time. Our results indicate that climate conditions and primary production affect the structural size of the skull, and we highlight the various potential responses of pine marten morphology and ecology to climate change. Recently, shifting population demographics resulting from these processes may constitute a threat to marten populations. Climate and environmental changes affect species' morphology and ecology, with different responses to shifting abiotic and biotic factors observed across species. Here, we tested how the structural body size of the pine marten and its population sex ratio shifted over time alongside climate change. We found that skull size, as a proxy of body size, increased in response to warmer and less snowy winters. However, changes in primary productivity rapidly shaped postorbital constriction regardless of shifts in body size, potentially demonstrating increased diet diversity in pine marten. Congruent with climate change, the population sex ratio has skewed towards males over time. Our results indicate that climate conditions and primary production affect the structural size of the skull, and we highlight the various potential responses of pine marten morphology and ecology to climate change.