Beyond the mountains: incorporating newly documented low-elevation records reshapes predicted habitat suitability for the threatened mountain skink Liopholis montana

Abstract

The mountain skink (Liopholis montana) is an alpine–montane specialist listed as Endangered under Australian legislation, with its Victorian distribution traditionally considered restricted to elevations >900 m. However, recent discoveries have revealed repeated, disjunct low-elevation records, including in the Wombat-Lerderderg area (as low as ~560 m elevation) and Dandenong Ranges (210 and 290 m elevation). We aimed to (i) document a newly discovered, coastal low-elevation record for the species, and (ii) test how including multiple low-elevation outliers influences inferred habitat suitability, potential distribution and conservation assessments for L. montana. We confirmed the identity of a ~20 m elevation record at Lake Tyers Beach (eastern Victoria) using genomic data. We subsequently fitted MaxEnt habitat suitability models (HSM) to a comprehensive, vetted occurrence dataset, comparing models calibrated with (i) core, high-elevation records only versus (ii) all records, including three low-elevation outlier sites (Wombat-Lerderderg, Dandenong Ranges, Lake Tyers Beach). Both models identified the south-eastern uplands as the core distribution area, but including low-elevation records substantially increased predicted suitable area at lower elevations and highlighted additional areas of potential habitat. Model outputs yielded updated estimates of extent of occurrence (EOO; 59,400 km2) and area of occupancy (AOO; 320 km2). Inclusion of low-elevation records influences predicted habitat suitability and range estimates for L. montana. Our results emphasise the need to continually scrutinise distributions of threatened montane fauna, as models calibrated only on core high-elevation records may fail to predict disjunct low-elevation occurrence sites of high conservation significance.