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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]

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: 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]

Context: Human activities are having a significant impact on biodiversity worldwide, to the extent that we are in the midst of the sixth mass extinction event. Although a substantial proportion of species globally have an elevated risk of extinction, some species are poorly known and there is insufficient information available to adequately assess their risk of extinction. Aims and methods: One such species is the glossy grass skink (Pseudemoia rawlinsoni), a widespread but enigmatic lizard species in south-eastern Australia. In order to improve our knowledge of its life history, and particularly its generation length, we examined museum specimens collected from across the range of the species, supplemented with measurements from field-caught individuals. Key results: We estimated that the species reaches sexual maturity in 3 years, at approximately 40 mm snout–vent length. Its generation length was estimated as 5 years. Sexual dimorphism was evident, and female body size was positively related to litter size. Although there was no evidence for substantial variation in morphology across the range of the glossy grass skink, a phylogeographic analysis using mitochondrial DNA sequence data (ND4) revealed the presence of seven genetic sublineages (up to 5.1% genetic divergence) within the species. Conclusions: The glossy grass skink appears to be a single, but widespread and genetically variable, species. Implications: Our study demonstrates how a targeted, multifaceted study can be effective at rapidly gathering data that can be used to contribute vital information to the assessment of extinction risk in Data Deficient species. Conservation efforts are often inhibited by a lack of information on a species; but we show it is possible to inform extinction risk with rapidly gathered data. We found that the glossy grass skink (Pseudemoia rawlinsoni) is a widespread, geographically variable species that matures in 3 years and has a generation length of 5 years. This information, in combination with other field-based studies, indicates that the glossy grass skink meets the criteria for listing as a threatened species. [ABSTRACT FROM AUTHOR]

Alternative phenotypes allow individuals to pursue different adaptive pathways in response to the same selective challenge. Colour polymorphic species with geographically varying morph frequencies may reflect multiple adaptations to spatial variables such as temperature and climate. We examined whether thermal biology differed between colour morphs of an Australian lizard, the delicate skink, Lampropholis delicata. The delicate skink has two colour pattern morphs, with frequencies varying across latitude and sex: plain (darker, more common at temperate latitudes, more common in males) or striped (lighter, more common at lower latitudes, more common in females). We tested heating and cooling rate, sprint speed, thermal preference, field body temperature and metabolic rate in both morphs and sexes to determine any link between colour and morph frequency distribution. Plain individuals heated more quickly, but other thermal traits showed little variation among morphs. Lampropholis delicata colour influences rates of heat exchange, but the relationship does not appear to be adaptive, suggesting that behavioural thermoregulation homogenises body temperature in the field. While we find no substantial evidence of thermal differences between the two colour morphs, morph-specific behaviour may buffer against differences in heat exchange. Latitudinal variation in species colour may be driven by selection pressures other than temperature. • We investigated thermal differences between colour morphs of an Australian lizard species. • Plain individuals heated faster than patterned individuals. • But otherwise, there was little thermal variation between the two morphs. • Morph-specific behaviour may buffer against differences in heating rate. • We found no evidence for the presence of alternative thermal phenotypes. [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]

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]

In animals, the success of particular lineages can be measured in terms of their number of species, the extent of their geographic range, the breadth of their habitats and ecological niches, and the diversity of their morphological and life‐history traits. Here, we review the distribution, ecology, morphology and life history of skinks, a diverse lineage of terrestrial vertebrates. We compared key traits between the three subfamilies of skinks, and between skinks and non‐scincid lizards. There are currently 1743 described species of skink, which represent 24% of global lizard diversity. Since 2010, 16% of lizard descriptions have been of skinks. The centres of skink diversity are in Australia, New Guinea, southeast Asia, Oceania, Madagascar and central Africa. Compared with non‐scincid lizards, skinks have larger distributional ranges, but smaller body sizes. Sexual size dimorphism is rare in skinks. Almost a quarter (23%) of skinks exhibit limb reduction or loss, compared with just 3% of non‐scincid lizards. Skinks are more likely to be viviparous (34% of species) compared with non‐scincids (13%), and have higher clutch/litter sizes than non‐scincids. Although skinks mature later than non‐scincids, their longevity is similar to that exhibited by other lizard groups. Most skinks (88%) are active foragers, and they are more likely to be carnivorous than non‐scincids. Skinks are more likely to be diurnal or cathemeral than other lizard groups, but they generally have lower field body temperatures compared with non‐scincids. The success of skinks appears to be both a result of them hitting upon a winning body plan and ecology, and their capacity to regularly deviate from this body plan and adapt their ecology and life history (e.g. repeated limb reduction and loss, transitions to viviparity) to prevailing conditions. [ABSTRACT FROM AUTHOR]

Conservation management cannot proceed in the absence of the basic ecological data necessary to develop conservation strategies for a species. Species considered Data Deficient and possibly extinct are poorly known, and are often overlooked in conservation planning. This is despite a growing body of evidence indicating that Data Deficient species are more likely to be threatened by extinction compared to well‐studied taxa. Hence, there is an immediate need to resolve data deficiency, and to search for species that are possibly extinct. Here, we conducted the first systematic search for a Data Deficient Australian skink, Lampropholis elongata (long sunskink), which prior to our study, had not been seen for approximately 9 years. A combination of pitfall trapping and active searches was used in attempt to detect the species. We rediscovered L. elongata at four sites within its known distribution on the southern edge of the New England Tablelands Bioregion in New South Wales, Australia. Our findings suggest that the species can be detected relatively easily using active survey methods, especially by inspecting tussock bases. We further highlight that areas of high canopy openness and high cover of Poa sieberiana (grey tussock‐grass) appear to be key habitat for the species. [ABSTRACT FROM AUTHOR]

Many animals have strict diel activity patterns, with unique adaptations for either diurnal or nocturnal activity. Diel activity is phylogenetically conserved, yet evolutionary shifts in diel activity occur and lead to important changes in an organism's morphology, physiology, and behavior. We use phylogenetic comparative methods to examine the evolutionary history of diel activity in skinks, one of the largest families of terrestrial vertebrates. We examine how diel patterns are associated with microhabitat, ambient temperatures, and morphology. We found support for a nondiurnal ancestral skink. Strict diurnality in crown group skinks only evolved during the Paleogene. Nocturnal habits are associated with fossorial activity, limb reduction and loss, and warm temperatures. Our results shed light on the evolution of diel activity patterns in a large radiation of terrestrial ectotherms and reveal how both intrinsic biotic and extrinsic abiotic factors can shape the evolution of animal activity patterns. [ABSTRACT FROM AUTHOR]