Basic and Applied Herpetology

Morphometric variation of the Asian Water Monitor Lizard (Varanus salvator) in different habitats in Peninsular Malaysia: a model analysis with machine learning

2025-07-07T11:00:42+00:00

The Asian water monitor lizard, Varanus salvator, is a widespread carnivorous reptile in Malaysia, but little is known about how habitat disturbance affects its morphology. This study analyzed 168 individuals across urban, agricultural, and forest habitats, using a Boruta algorithm and logistic regression to identify and validate morphological predictors of habitat. Allometric traits, including relative skull length, tail length, and thigh width, were better predictors of habitat differences than absolute measures such as snout-vent length (SVL) and snout-tail length (STL). Generally, urban and forest habitats exhibited similar variations in traits, but urban populations exhibited larger relative and absolute skull lengths, potentially linked to ecological or competitive advantages. In contrast, agricultural habitats displayed smaller traits, including relative tail length and thigh width, potentially reflecting pressures from predation or competition, resource limitations, or female-biased populations. Despite these differences, body condition and absolute size measurements were consistent across habitats, indicating populations in disturbed habitats maintain comparable sizes and energy reserves. While the species demonstrates adaptability to disturbance, further research is needed to explore ecological pressures in agricultural habitats and their potential impacts on the long-term fitness and population dynamics of V. salvator.

Short-term effects of wildfire on Canary Islands’ endemic lizards

2025-01-30T15:21:31+00:00

The Macaronesia bioregion is experiencing an increase in the frequency, intensity and magnitude of fires. However, the impact that this new fire regime may have on the endemic fauna and flora of many islands, such as those of the Canary archipelago, is unknown. In this study we analyzed the short-term response of the Gallot’s lizard, Gallotia galloti, to a fire that occurred in the northwestern part of La Palma in the summer of 2023. We carried out 187 linear transects in burned and unburned pine forest and mountain scrub plots in June, July, and September 2024, hence, almost a year after the fire. We observed a total of 333 lizards, and the Generalized Linear Mixed Model did not detect differences in lizard abundances between burned and unburned areas. The presence of juvenile lizards in the burned areas evidences the survival of the eggs after the fire. However, we also found a significant reduction of hatchling lizards in burned areas in September 2024, i.e. the second generation born after the fire, indicating that short-term burned areas can compromise the viability of the populations. These results suggest that the Gallot’s lizard can persist in the face of fire in the short term, although environmental harsh conditions could hinder its resilience in the mid-term.

Atlas of amphibians and reptiles in the Moroccan section of the Mediterranean Intercontinental Biosphere Reserve: distribution patterns and habitat use

2025-06-10T14:56:12+00:00

This study presents the first comprehensive atlas of the distribution of amphibians and reptiles within the Moroccan section of the Intercontinental Biosphere Reserve of the Mediterranean (IBRM). Data were gathered from literature reviews, museum collections, and extensive field surveys conducted between 2008 and 2019. A Geographical Information System (GIS) was utilized to generate updated distribution maps, assess species richness within a 10x10 km UTM grid, and analyse associations of species with habitat categories. A total of eight amphibian and 25 reptile species, representing five and 17 families, respectively, were recorded. Three distinct distribution patterns emerged for both taxonomic groups: widespread species, species restricted to specific environments, such as high-altitude areas or coastal environments, and species with limited and / or fragmented ranges. Seventeen areas of high species richness (N > 10 species) were identified across the study area. These areas consistently overlapped across both taxonomic groups and were primarily associated with Mediterranean-type habitats. While amphibians exhibited relatively homogeneous habitat preferences, reptiles demonstrated four distinct assemblages: species prefer mixed vegetation mosaics; species occupy forest-agriculture edges; species adaptable to diverse habitats and environments and species privilege open grasslands-rocky areas. The IBRM’s complex topography likely contributes to high levels of environmental diversity, supporting a remarkable proportion of Morocco’s herpetofauna: 60% of amphibian species and 25% of reptile species. These findings underscore the critical importance of the Moroccan IBRM for herpetofaunal conservation at the national and international levels.