Social Structure and Habitat Use of New Caledonian Leopard Skinks (Scincidae: Lacertoides Pardalis): A Radiotelemetric Study
Selection and implementation of conservation measures require in-depth knowledge of ecology and biology of target species. Translocations of reptile populations are particularly likely to fail if basic habitat requirements and social structure are overlooked. Leopard Skinks (Lacertoides pardalis) are a vulnerable lizard species restricted to maquis shrublands on the nickel-rich ultramafic soils of New Caledonia, on the front line in the face of growing pressure from mining activities. Their extreme wariness limits observations and opportunities for ecological studies. We radio-tracked Leopard Skinks from two contrasting populations at the end of the warm season, after annual reproduction, to provide baseline data on home ranges, intraspecific relationships, and habitat preferences for future conservation actions. Mean seasonal home range area calculated by Autocorrelated Kernel Density Estimation was 4350.7 m². Apparent sex ratio was strongly in favor of females (80% of sexually mature specimens detected), and we observed stable groups of a few females and one male, with home ranges largely overlapping. Leopard Skinks occupy a range of open to closed, forest-like maquis vegetation and rely on rocky microhabitats for shelter, but also daily activities. Shelter sites are carefully selected and used by several individuals. This study offers rare observations of the social structure of Leopard Skinks, and our results call for caution in design of translocation operations.Abstract
Map of New Caledonia showing locations of study sites with pictures of typical habitats.
Gray areas represent ultramafic massifs known to be occupied by Leopard Skinks (Lacertoides pardalis). Photographs by Matthias Deuss. Source of map data: Government of New Caledonia (https://georep.nc/).
Subadult male Leopard Skink (Lacertoides pardalis) equipped with a 0.90 g VHF transmitter, basking in the early morning next to its rocky retreat at site A.
Photograph by Matthias Deuss.
Microhabitat variables measured at relocation points during activity periods of Leopard Skinks (Lacertoides pardalis), expressed as percentage ground cover on circles of 1 m radius compared to random sites at site A and B.
Levels of significance for Wilcoxon tests are given above each variable; ns: P > 0.05, *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, ****P ≤ 0.0001.
Principal Component Analyses of microhabitat variables measured at relocation points during activity periods of Leopard Skinks (Lacertoides pardalis) at site A and B.
Ellipses represent 95% standard deviation for relocation data (blue) and random points (red).
Shelter types used by Leopard Skinks (Lacertoides pardalis); n = 12 and 23 at sites A and B respectively.
Home ranges of radio-tracked Leopard Skinks (Lacertoides pardalis) calculated by Autocorrelated Kernel Density Estimates (AKDE) at site A (above) and B (below).
Both maps are at the same magnification to allow direct comparison. Core areas (50% AKDE) are delimited by dashed lines and seasonal home ranges (95% AKDE) by plain lines. Source of map data: Government of New Caledonia (https://georep.nc/).
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