Protected areas serve as climate refugia by reducing thermal stress in lizards

Abstract

Protected areas (PAs) are key to current strategies for biodiversity conservation and have been designed to safeguard species from direct anthropogenic threats. PAs are also expected to buffer biodiversity from the impacts of climate change, yet their effectiveness in reducing climate-related stress (e.g., heat stress) for organisms remains poorly understood. Here, we tested whether PAs serve as climate refuges for small ectotherms, the Australian Lampropholis skinks, by combining species-specific physiological data with biophysical modelling. We simulated environmental and physiological conditions across thousands of locations inside and outside PAs under present, +2 °C, and +4 °C climate scenarios to derive key thermal stress metrics — thermal safety margin (TSM), hours above critical thermal maximum (CTmax), and daily activity hours. Our results show that PAs can buffer skinks from heat stress by increasing TSMs, reducing exposure to temperatures above CTmax, and maintaining higher activity time under current and climate change scenarios. These benefits were strongest at low latitudes, where thermal stress is most intense, and varied among species depending on their physiological traits and ecological specialisation. Species with broader thermal tolerances experienced greater benefits from protection. Our findings demonstrate that PAs can mitigate climate stress in ectotherms, especially in tropical regions. As climate change intensifies, incorporating mechanistic models into conservation planning can guide the strategic design and management of PAs to support species persistence under climate change.