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For most species, the factors that determine geographical range limits are unknown. In mesic-adapted species, populations occurring near the edge of the species' distribution provide ideal study systems to investigate what limits distributional ranges. We aimed to identify the abiotic constraints that preclude an east-Australian mesic-adapted lizard (Lampropholis delicata) from occupying arid environments. We performed lizard surveys at sites spanning an elevation/aridity gradient (380–1070 m) and measured the prevalence of habitat features (logs, rocks, leaf litter, bare ground, solar radiation) in addition to hourly temperatures in a variety of microhabitats available to lizards. Species distribution models (SDM) were used to identify the macroclimatic variables limiting the species' distribution. At its inland range limit, L. delicata is associated with mesic high-elevation forests with complex microhabitat structures, which gradually decline in availability toward lower (and more arid) elevations where the species is absent. Moreover, L. delicata is absent from sites with a shallow leaf litter layer, in which daily temperatures exceed the species' thermal preference range, which we determined in a laboratory thermal gradient. In regards to macroclimate, SDM revealed that temperature seasonality is the primary variable predicting the species' distribution, suggesting that L. delicata avoids inland areas owing to their high annual thermal variability. By combining multiple lines of evidence, this research highlights that habitat and microclimate suitability—not solely macroclimate suitability—are important range-limiting factors for mesic ectotherms and should be incorporated in studies addressing range-limiting hypotheses. [ABSTRACT FROM AUTHOR]

The ever‐increasing and expanding globalisation of trade and transport underpins the escalating global problem of biological invasions. Developing biosecurity infrastructures is crucial to anticipate and prevent the transport and introduction of invasive alien species. Still, robust and defensible forecasts of potential invaders are rare, especially for species without known invasion history. Here, we aim to support decision‐making by developing a quantitative invasion risk assessment tool based on invasion syndromes (i.e., generalising typical attributes of invasive alien species). We implemented a workflow based on 'Multiple Imputation with Chain Equation' to estimate invasion syndromes from imputed datasets of species' life‐history and ecological traits and macroecological patterns. Importantly, our models disentangle the factors explaining (i) transport and introduction and (ii) establishment. We showcase our tool by modelling the invasion syndromes of 466 amphibians and reptile species with invasion history. Then, we project these models to amphibians and reptiles worldwide (16,236 species [c.76% global coverage]) to identify species with a risk of being unintentionally transported and introduced, and risk of establishing alien populations. Our invasion syndrome models showed high predictive accuracy with a good balance between specificity and generality. Unintentionally transported and introduced species tend to be common and thrive well in human‐disturbed habitats. In contrast, those with established alien populations tend to be large‐sized, are habitat generalists, thrive well in human‐disturbed habitats, and have large native geographic ranges. We forecast that 160 amphibians and reptiles without known invasion history could be unintentionally transported and introduced in the future. Among them, 57 species have a high risk of establishing alien populations. Our reliable, reproducible, transferable, statistically robust and scientifically defensible quantitative invasion risk assessment tool is a significant new addition to the suite of decision‐support tools needed for developing a future‐proof preventative biosecurity globally. [ABSTRACT FROM AUTHOR]

Context: Knowledge of species' distribution and habitat associations is fundamental for conservation planning and management, especially in the context of range-restricted taxa. The Critically Endangered Kaputar rock skink (Egernia roomi) is a high elevation species that is restricted to the Nandewar Ranges (New South Wales, Australia). The species was not formally recognised until 2019, with its distribution, ecology, and threats poorly known. Aims: To determine the geographical distribution of the Kaputar rock skink and explore its ecology and threats. Methods: We performed surveys throughout high elevation regions of Mount Kaputar National Park, targeting suitable habitat for the Kaputar rock skink (rock outcrops and plateaux). Species distributional modelling (SDM) was used to identify potentially suitable habitat outside of our search areas. Key results: We detected the species at all historical record sites and at 15 new sites, increasing the species' known area of occupancy (AOO) four-fold (from 8 km2 to 40 km2), and elevational range three-fold (from 1360–1480 m to 1147–1509 m). Conclusion: The AOO for the species now exceeds the IUCN Red List threshold for Critically Endangered, but falls within the range for Endangered under Criterion B. Our SDMs indicated that all predicted suitable habitat for the species falls within the region that we surveyed in this study. Implications: Our study provides valuable information on the geographic range of a threatened lizard species and evaluates the potential impact of large-scale fires on the persistence of the species. The Kaputar rock skink (Egernia roomi) was only formally recognised as a species in 2019, with little known about its distribution and ecology. Given its miniscule distribution, it was federally listed as Critically Endangered, despite no further formal survey work. Here, we use field surveys as well as species distributional modelling to ascertain the species'true range and its threats. [ABSTRACT FROM AUTHOR]

Aim: Squamate fitness is affected by body temperature, which in turn is influenced by environmental temperatures and, in many species, by exposure to solar radiation. The biophysical drivers of body temperature have been widely studied, but we lack an integrative synthesis of actual body temperatures experienced in the field, and their relationships to environmental temperatures, across phylogeny, behaviour and climate. Location: Global (25 countries on six continents). Taxa: Squamates (210 species, representing 25 families). Methods: We measured the body temperatures of 20,231 individuals of squamates in the field while they were active. We examined how body temperatures vary with substrate and air temperatures across taxa, climates and behaviours (basking and diel activity). Results: Heliothermic lizards had the highest body temperatures. Their body temperatures were the most weakly correlated with substrate and air temperatures. Body temperatures of non‐heliothermic diurnal lizards were similar to heliotherms in relation to air temperature, but similar to nocturnal species in relation to substrate temperatures. The correlation of body temperature with air and substrate temperatures was stronger in diurnal snakes and non‐heliothermic lizards than in heliotherms. Body‐substrate and body‐air temperature correlations varied with mean annual temperatures in all diurnal squamates, especially in heliotherms. Thermal relations vary with behaviour (heliothermy, nocturnality) in cold climates but converge towards the same relation in warm climates. Non‐heliotherms and nocturnal species body temperatures are better explained by substrate temperature than by air temperature. Body temperature distributions become left‐skewed in warmer‐bodied species, especially in colder climates. Main Conclusions: Squamate body temperatures, their frequency distributions and their relation to environmental temperature, are globally influenced by behavioural and climatic factors. For all temperatures and climates, heliothermic species' body temperatures are consistently higher and more stable than in other species, but in regions with warmer climate these differences become less pronounced. A comparable variation was found in non‐heliotherms, but in not nocturnal species whose body temperatures were similar to air and substrate irrespective of the macroclimatic context. [ABSTRACT FROM AUTHOR]

Aim: In wide‐ranging taxa occupying broad climate gradients, alternative colour pattern variants (i.e. morphs) may emerge as an adaptive response to local climatic regimes. We explore the patterns of geographical segregation among colour morphs of the Lace monitor and determine whether morphs occupy divergent climatic niches along a mesic–arid gradient. Location: Eastern and south‐eastern Australia. Taxon: Varanus varius. Methods: We compiled a dataset of crowdsourced, georeferenced photographic records (n = 1637) of V. varius and scored each photographed lizard as one of two discrete colour pattern phenotypes—Lace morph (mostly dark with fine pale patterning) or Bell's morph (broad yellow and black bands). We then analysed the geographical segregation of colour morphs under an exploratory point‐pattern process analysis framework. Finally, we quantified similarities and differences between each colour morphs' realised climatic niche in univariate and multivariate (i.e. Centroid shift, Overlap, Unfilling, and Expansion and n‐dimensional hypervolume frameworks) environmental space. Results: While both morphs co‐occur over much of the species' range, there is a coastal–inland clinal transition in the relative densities of the morphs' occurrences—the Bell's morph becomes the more prevalent phenotype towards inland locations and is rare or absent towards coastal regions. Analysis of the realised climatic niches shows that the Bell's morph exploits areas that are relatively more arid, receive more solar irradiation and experience a broader range of thermal extremes than those occupied by the Lace morph. Main conclusions: The mesic–arid transition zone in eastern Australia is a primary axis of environmental variation over which geographical variation in colour polymorphism has emerged in V. varius. More broadly, this study demonstrates how photographs from citizen science platforms can be used to explore geographical variation in colour polymorphisms without needing to conduct expensive, time‐consuming field studies on wild organisms. [ABSTRACT FROM AUTHOR]