Disentangling the role of heat sources on microhabitat selection of two Neotropical lizard species

Effects of habitat perturbation on lizard assemblages in the center-west of the Arid Chaco region, Argentina

Several human disturbances contribute to the decrease of vertebrate species' richness and abundance, altering the processes of an ecosystem. We evaluate richness, diversity and relative abundance of species for lizard assemblages at sites with different degrees of perturbation in the center-west of the Arid Chaco region in Argentina. Between 2015 and 2018, six lizard assemblages were sampled monthly -using pitfall traps- in three areas of the Chaco, with a perturbed and an unperturbed (control) replica at each of the areas: (1) Chaco Mountain plain, (2) Chaco Mountain slope, and (3) Chaco Plains, and habitat characteristics of each study site were recorded. We captured 1446 lizards, belonging to 12 species. The perturbed area at the Chaco Mountain plain showed the greatest richness, diversity and abundance of species. In the perturbed Chaco Plains, species abundance decreased by about 50% with respect to the control site. Liolaemus chacoensis was the dominant species at all sites. Some species could be negatively affected by a total loss of arboreal strata, tree trunks and fallen leaves. Structural parameters of lizard assemblages were related to the habitat characteristics; therefore, these results provide information for the conservation and management of lands and lizard assemblages in the Arid Chaco.

Extrinsic traits consistently drive microhabitat decisions of an arboreal snake, independently of sex and personality

One pivotal topic on habitat selection is to understand the influence of intrinsic and extrinsic factors on the selection process. Although the effect of some extrinsic variables and sex has been extensively studied, almost nothing is known about the effect of personality, particularly on snakes. Here we addressed the relative importance of extrinsic (tree-related) and intrinsic (sex and personality) factors driving microhabitat selection decisions of a nocturnal tree snake (Leptodeira annulata). We implemented a protocol to quantify the influence of personality and sex on the role of extrinsic variables on microhabitat selection. First, we conducted three behavioral experiments to extract the shyness-boldness and avoidance-exploitation personality traits of male snakes. Then, we evaluated the role of sex and personality on the effect of tree-traits (thickness, canopy cover and shelter availability) on microhabitat selection, using two-step conditional logistic regression. Snakes consistently selected tree trunks, preferably thick and with high canopy cover and shelter availability, independently of their sex of personality. For this species, only extrinsic variables determined microhabitat decisions. Our protocol will aid to quantify the role of personality on microhabitat selection of other species and understand whether this is an important variable in habitat decision-making or not.

Vulnerability to climate change of a microendemic lizard species from the central Andes

Given the rapid loss of biodiversity as consequence of climate change, greater knowledge of ecophysiological and natural history traits are crucial to determine which environmental factors induce stress and drive the decline of threatened species. Liolaemus montanezi (Liolaemidae), a xeric-adapted lizard occurring only in a small geographic range in west-central Argentina, constitutes an excellent model for studies on the threats of climate change on such microendemic species. We describe field data on activity patterns, use of microhabitat, behavioral thermoregulation, and physiology to produce species distribution models (SDMs) based on climate and ecophysiological data. Liolaemus montanezi inhabits a thermally harsh environment which remarkably impacts their activity and thermoregulation. The species shows a daily bimodal pattern of activity and mostly occupies shaded microenvironments. Although the individuals thermoregulate at body temperatures below their thermal preference they avoid high-temperature microenvironments probably to avoid overheating. The population currently persists because of the important role of the habitat physiognomy and not because of niche tracking, seemingly prevented by major rivers that form boundaries of their geographic range. We found evidence of habitat opportunities in the current range and adjacent areas that will likely remain suitable to the year 2070, reinforcing the relevance of the river floodplain for the species’ avoidance of extinction.