Microhabitat Preferences, Climate Vulnerability and Conservation Status of the High-Elevation Orange-Speckled Forest Skink (Tumbunascincus luteilateralis)

Abstract

High-elevation species are particularly vulnerable to climate change due to their restricted distributions and reliance on stable, cool climates. Tumbunascincus luteilateralis (the orange-speckled forest skink), a high-elevation lizard endemic to the Eungella region in central Queensland, Australia, is currently listed as Data Deficient under the International Union of Conservation of Nature (IUCN) Red List of Threatened Species. Our study integrates field surveys, microhabitat analyses and ecological niche modelling to better understand the species' distribution, habitat preferences and conservation status. Field surveys detected T. luteilateralis at many new locations all within a highly restricted area on the Dalrymple Plateau. It occurred in a range of forest types above 800 m elevation, but very rarely occurred below 800 m, showing a strong ecological preference for high-elevation rainforests. Microhabitat analyses indicated that the species exhibits significant selection for warmer, refuge-rich sites characterised by higher log cover and larger logs, which likely support thermoregulation and predator avoidance. Ecological niche modelling highlighted that the species' current distribution is restricted to stable, cool climates typical of high-elevation rainforests, with no evidence of occurrence outside the Eungella region. Projections under future climate change indicate a severe reduction in suitable habitat, with complete loss predicted by the end of the century under a moderate warming scenario. These results show that T. luteilateralis meets the criteria for Endangered status under the IUCN Red List, with an extent of occurrence of 687 km² and area of occupancy of 169 km². Efforts that could help maintain or improve population resilience include protection of the rainforest habitat from bushfires, preservation of large log refugia and reducing the risk of predation from feral animals. This study underscores the need for conservation-oriented ecological studies on narrow-ranged, high-elevation species to understand their conservation status and inform conservation planning.