Abstract
The high mountain environment is a tough habitat that imposes many challenges to reptiles. As temperature decreases with altitude and has a dramatic variation throughout the day in the tropical mountains, ectotherms must cope with these harsh conditions. We studied the use of microhabitat and activity patterns of Stenocercus trachycephalus in the eastern Andes mountain range of Colombia. Three localities were sampled across the wide altitudinal distribution of this lizard species, in a range from 2,670 to 3,950 m a.s.l. The initial hypothesis was that these natural history traits would change with altitude but instead, we found that they remained roughly consistent, showing the great plasticity of this species. The results support that this lizard is a microhabitat-generalist using principally herb across the gradient, rarely shifting to specific plants or microhabitats such as rocks depending on availability. Regarding the activity pattern, this species was active throughout the day from 8:00 to 16:00 with a similar pattern along the gradient. Nevertheless, some differences were detected across localities. The activity pattern shifted from bimodal in the lower locality to unimodal in the higher ones. As expected, a correlation between temperature and activity patterns was found in one of the study sites. However, this was not the case for the lower and mid-elevation localities, where there was no correlation between these variables. The mid-elevation study site was the most interesting locality as the use of microhabitat relied virtually just on the herb stratum and the activity was constrained to the morning hours. These findings may be the result of the synergic effects of other ecological variables (weather variability, human impact, predation, population structure, or reproductive season). Our study gives the basis for a better understanding of how behavior (microhabitat choice and hours of activity) of ectotherms can help to counter thermal constraints in the neotropics when facing an altitudinal gradient. Further studies should focus on the thermal biology of this species, considering the influence of anthropic impact on these lizards’ populations.
Highlights
Elevation shapes the ecology of species and populations by determining its habitat temperature, humidity, radiation, pressure, and vegetation (Heatwole, 2009; Buckley et al, 2013; SiliceoCantero et al, 2016)
A total of 111 individuals of S. trachycephalus were observed across the three study sites
We studied two natural history traits of S. trachycephalus across a 1,280 m elevation gradient, as it shapes multiple ecological variables of this lizard’s habitats
Summary
Elevation shapes the ecology of species and populations by determining its habitat temperature, humidity, radiation, pressure, and vegetation (Heatwole, 2009; Buckley et al, 2013; SiliceoCantero et al, 2016). Altitudinal changes can modulate adaptation of ecological traits of species (Hertz & Huey, 1981; Ballinger, 1983; Adolph & Porter, 1993; Fierro-Estrada et al, 2019) or promote the expansion of their physiological tolerance and the scope of thermal plasticity (Van Sluys et al, 2004; Méndez-Galeano et al, 2020) Both hypotheses have been previously tested in different studies demonstrating the importance of evaluating ecological variables in different populations along gradients (Grant & Dunham, 1990; Adolph & Porter, 1993; Vitt et al, 2007; Fierro-Estrada et al, 2019; Gilbert & Miles, 2019)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
