Living in a cold tropical mountain: do the microhabitat use and activity pattern change with elevation in the high-Andean lizard Stenocercus trachycephalus (Squamata: Tropiduridae)?

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

Revealing the pathways to scale out agricultural transformation : factors influencing adoption of silvopastoral systems

In Latin America, the expansion of land for Extensive Cattle Ranching (ECR) is the leading driver of deforestation causing unsustainable levels of environmental degradation and social vulnerability. Silvopastoral Systems (SPS) are a promising agroecological alternative for cattle production that combines trees and shrubs with forage grasses to enhance cattle production and landscape heterogeneity. Despite strong evidence of SPS benefits including biodiversity conservation, increase in productivity, soil recovery, and deforestation avoidance, its adoption remains low. Previous research made on silvopastoral adoption is limited in sample sizes and has considered adoption as a binary option. This research aimed to determine how SPS can be scaled out by identifying the enabling and constraining factors for adoption in Latin America. First, I synthesized the findings on adoption of SPS in the region with a systematic literature review (n= 52). Second, I analyzed a large socio-economic dataset on 2900 farms in Colombia, collected during the Sustainable Cattle Ranching project in combination with open access farm environmental information using mixed effects linear models to understand the determinants of SPS adoption extension. Key enablers of SPS adoption include economic incentives such as payments for ecosystem services (PES), and information transfer capacity such as presence of technical assistance (TA) or strength of social networks (e.g., distance to closest neighbor) that highlights SPS benefits (e.g., ecosystem services provided) increasing positive perceptions on the systems and knowledge on its management. Additionally, farm characteristics such as presence of forest or watershed on the farm, and high levels of soil erosion positively influence adoption of SPS. Conversely, barriers to adoption of SPS are its management complexity, cost of implementation, and limited market demand for products generated under SPS. Environmental aspects such as water demand and hydric vulnerability also have a constraining effect on adoption. Scaling out SPS in Latin America will depend on economic incentives capable of overcoming the initial investment cost for farmers, information transfer on SPS, stimulation of demand for SPS products, and the environmental conditions experienced by the farms. Widespread SPS adoption can increase cattle production sustainability mitigating the adverse effects of ECR.Science, Faculty ofResources, Environment and Sustainability (IRES), Institute forGraduat