Ontogenetic Habitat Use and Density of the Green Lizard (Lacerta bilineata) in Contrasted Landscapes in France and Italy

Abstract

Habitat modification is a major factor in the decline of reptile populations. The degree of the decline has been shown to be directly related to the intensity of habitat modification. Farming practices and urbanization are just two of the factors involved indicating that the development of practices that minimize or cancel anthropogenic impacts is urgently needed to prevent further declines. This requires knowledge of population ecology of reptiles in both disturbed and pristine habitats. In this paper, we describe aspects of green lizard (Lacerta bilineata) population ecology in a forest–pasture relatively pristine mosaic habitat in central Italy and a fragmented habitat in western France. In Italy, habitat niche overlap was very high between males and females but very low between males and juveniles. For male and female abundances, general linear models showed that the adult abundances increased with the increase of Rubus bushes, whereas juvenile abundance increased with the increase of Spartium bushes. Contingency table analysis showed that juveniles were also much more frequently observed in grasslands than adults of either sexes. The observed ontogenetic structural niche pattern was likely due to intraspecific competition avoidance, competition interference, and cannibalism. The persistence of the same patterns across years demonstrates a temporal stability of the ontogenetic structural niche pattern. Over the length of the study period, population densities were stable in the Italian population, but densities were much higher by around five times in the hedgerow in the fragmented habitat in France. In the hedgerow, monthly lizard presence was uneven, with the greatest number of sightings in June and July. Overall, our study provided no support for the notion that lizard abundance/density should be lower in modified compared to unmodified habitats, and clearly revealed that a careful management of the hedgerows is crucial for the conservation of this lizard species in agro-forest ecosystems.

Testing hypotheses of habitat use and temporal activity in relation to body plan in a Mediterranean lizard community

“…Concerning hypothesis 2, the wider habitat niche breadth of the largest bodied species (L. with adults being significantly more generalized (Rugiero et al 2021). This is a further confirmation that it is the body size, and not other ecological characteristics, that is strongly associated with the wider habitat niche breadth of this species.…”

“…Furthermore, habitat niche breadth was nearly identical in 1-2 years-old juvenile L. bilineata population cohorts in comparison to similarly-sized lizards of other species. Intraspecific competition avoidance and cannibalism appear to be the main reasons pushing juveniles to minimize habitat overlap with adults in the large-sized L. bilineata at these study areas (Rugiero et al 2021). The same pattern was also recorded from Anolis lizards, with adult male density having significant effects on juvenile perch height, perch width, and substrate use, thus suggesting that strong age-class competition may contribute to the ontogenetic differences in habitat choice Warner 2017a, 2017b).…”

“…Details of the monitoring protocol were described by Rugiero et al (2021) for L. bilineata. In the present paper, we also include the dataset presented in Rugiero et al (2021). Monitoring was conducted during April-October 1991, 1992, 1993, and 1997.…”

Application of Univariate Diversity Metrics to the Study of the Population Ecology of the Lizard Lacerta bilineata in an Ecotonal Habitat

“…The individuals recorded after the midsummer gap may represent transients rather than lizards occupying the habitat leading up to hibernation, since most of them were absent during the following year. These changing population dynamics during autumn may involve intraspecific aggression in L. bilineata, with many individuals generally being intolerant of other adults and with juveniles, particularly outside the reproductive season, involving serious injuries and mortalities due to conflicts between adults of both sexes [19,38]. The narrow linear nature of hedgerow systems potentially increases contact between individuals during movement.…”

Natural Diet of European Green Lizards, Lacerta viridis (Squamata: Lacertidae): A Comparison of Macroscopic and Molecular Identification Methods

“…Arthropods, such as Araneae, Coleoptera, Hymenoptera, and Orthoptera, appear to be their primary prey (Korsós 1984; Maier et al 2020). Due to its large body size, the lizard can occasionally even catch small vertebrates, including other lacertids and conspecifics (Nettmann and Rykena 1984; Leu and Petrovan 2022), which is also typical for other taxonomically related species (Angelici et al 1997; Rugiero et al 2021). Previous dietary studies conducted on related species showed that diet composition changes with body size, age, and season (Angelici et al 1997; Crovetto and Salvidio 2013; Sagonas et al 2018).…”