Demographic and life history variation in two sky‐island populations of an endangered alpine lizard

Abstract

A species' life history is a strong determinant of its risk of extinction; traits such as body size, growth rate, age at maturity and fecundity influence population viability and persistence, as well as capacity for dispersal and colonisation of new habitats. Yet, despite the potential for substantial geographic variation in life history, most conservation programmes rely upon the species average rather than information specific to individual populations. We use the Guthega Skink (Liopholis guthega), a threatened alpine endemic lizard restricted to two geographically isolated locations in southeastern Australia, as a case study to demonstrate how geographic variation in life history traits may better inform conservation management. Liopholis guthega has a relatively short life span, with only a few years of reproductive activity, inter-annual variation in reproductive output, and less-than-annual reproduction. We show that the Victorian population has a significantly slower growth rate, attains a smaller maximum size, reaches reproductive maturity later, and produces significantly smaller litters, despite no difference in longevity suggesting that it may be more vulnerable to extinction. We, therefore, suggest evaluating genetic rescue from the New South Wales population to improve recruitment and longevity of Victorian L. guthega, ongoing population monitoring in both locations, and a dedicated pest control programme to reduce pressure on this population. Our study has far reaching impacts; primarily demonstrating how knowledge of geographic variation in life history has the potential to improve conservation management of threatened species.

Determining the generation length and level of morphological and genetic differentiation in the Data Deficient glossy grass skink (Pseudemoia rawlinsoni)

“…other similar-sized viviparous skink species in south-eastern Australia (Hutchinson and Donnellan 1992;Chapple 2006;Atkins et al 2020;Greer 2022). Importantly, our study represents the first detailed determination of the generation length of a Pseudemoia species (Greer 2022).…”

Age structure and growth pattern of a high‐altitude lizard population based on age determination by skeletochronology

“…The sex of each individual was determined based on the presence or absence of a hemipenis (hatchlings were euthanized to determine sex by dissection). Females were palpated to detect developing embryos and determine whether they were pregnant (Atkins et al, 2019). The minimum age of pregnancy is considered to be the age of sexual maturity in females.…”

Nomenclature of supra-generic units within the Family Scincidae (Squamata)

“…The Egerniini of Welch (1982), and the earlier Egernina of De Vis (1888), which need to be treated as independent due to the different stems employed in the formation of the names, apply to a much more geographically restricted (Australia, the Solomon Islands, New Guinea and the Maluku Archipelago of Indonesia) and less species-rich (62 species in 8 genera) lineage for which there have been many fewer uses of the terms Egerniini/Egerninae/Egernidae (although again the informal name Egernia group of Greer (1979) has a much greater usage). While I have been able to identify 40 uses of these names (with or without the double -i) since Welch (1982) created Egerniini (Egerniidae: Hedges & Conn 2012;Pyron et al 2013;Zug 2013;Hedges 2014;Sy 2015;Bahmani et al 2016Bahmani et al , 2018Feizi et al 2016;Paluh & Bauer 2017;Čerňaňský et al 2020;Čerňaňský & Syromyatnikova 2021;Egerniinae: Hitchmough et al 2016;Bull et al 2017;Halliwell et al 2017a-c;Atkins et al 2018Atkins et al , 2020Foster et al 2018;Norval et al 2018Norval et al , 2021Bower et al 2019;Chapple et al 2019Chapple et al , 2021Ortiz et al 2019;Thorn et al 2019Thorn et al , 2021Treilibs et al 2019;While et al 2019;Norval & Gardner 2020;Pearson et al 2020;Ridley et al 2020;Stampe et al 2020;Thompson et al 2020;Watson et al 2020…”