Biology subjects

Plazas-Cardona, D.

Publications and source records attributed to Plazas-Cardona, D..

3 recordsLinked to original sources

bioRxiv2025

Impacts of Habitat Transformation on Amphibian and Reptile Communities in a Heterogeneous Andean Landscape

Land-use change is a major driver of biodiversity loss in tropical montane ecosystems, yet its effects on herpetofaunal community structure remain insufficiently understood at local scales. We evaluated patterns of diversity and community structure of amphibians and reptiles across a gradient of habitat transformation in southwestern Cundinamarca, Colombia. Field surveys conducted between 2015 and 2022 using visual encounter surveys recorded 57 species and 608 individuals. Forest habitats supported the highest species richness and diversity, whereas coffee crops and open areas exhibited reduced richness and simplified assemblages. Rank-abundance patterns revealed greater dominance in open habitats and higher evenness in forests, consistent with environmental filtering processes. Amphibians were more strongly associated with forest environments, whereas reptiles showed broader habitat tolerance and higher representation in disturbed habitats. In addition, we compiled a comprehensive regional inventory based on field data, biological collections, and biodiversity databases, documenting 86 species of herpetofauna. Overall, our results show patterns consistent with environmental filtering, where habitat transformation is associated with increased dominance of generalist species and simplified community structure. These findings highlight the importance of conserving forest remnants and maintaining heterogeneous landscapes to support herpetofaunal diversity in the Colombian Andes.

ecology↗

bioRxiv2024

Competitive exclusion, experience-based learning, and human fishing, influence activity patterns in Juvenile and Adult Brown Pelicans (Pelecanus occidentalis)

The activity patterns of young and adult individuals offer insights into exclusion and adaptation dynamics in seabirds. Juveniles often show differences in their daily behaviors compared to adults, especially in activities like feeding. We focus in two contrasting hypotheses to explain the age-related differences in activity patterns of Brown Pelicans (Pelecanus occidentalis): the "competitive exclusion" hypothesis and the "experience-based adaptation" hypothesis. The competitive exclusion hypothesis posits that adult pelicans, with superior foraging skills, actively exclude juveniles from prime feeding areas, leading to temporal segregation. In contrast, the experience-based adaptation hypothesis suggests that juveniles exhibit different activity patterns as they undergo a learning process, gradually improving their foraging efficiency through trial and error. Using continuous focal sampling, we analyzed the activity peaks of both juveniles and adults, revealing significant temporal segregation between age groups. Additionally, the impact of human fishing activity on pelican behavior was assessed, showing alterations in natural foraging patterns. These findings contribute to the understanding of resource use and competition dynamics in seabirds and highlight the importance of considering both biological and anthropogenic factors when analyzing seabird behavior.

animal behavior and cognition↗

bioRxiv2023

Conserving Biodiversity in Coffee Agroecosystems: Insights from a Herpetofauna Study in the Colombian Andes with Sustainable Management Proposal

Amphibians and reptiles are important indicators of ecosystem health, yet their populations are declining worldwide due to habitat loss and climate change. Agroecosystems, such as coffee plantations, can provide important habitat for these species. We conducted field surveys in the Sumapaz region of Colombia to identify the microclimatic variables that influence the diversity and abundance of herpetofauna in coffee crops. The canonical correspondence analysis revealed that leaf litter abundance, crop area, and age category were the most important structural variables for determining herpetofauna diversity. Our findings suggest that coffee plantations function similarly to secondary vegetation, and maintaining a thick layer of leaf litter is critical for establishing complex and structured animal communities. This study proposes a set of sustainable agricultural management principles to promote the existence of amphibians and reptiles in coffee crops. By adopting these practices, it is possible to prevent the decline in the population of amphibians and reptiles due to the expansion of the agricultural frontier, as seen in other coffee-growing regions. The findings of this study contribute to a better understanding of how to balance agricultural production and biodiversity conservation in the context of agroecosystems. * Una version en espanol de este documento puede ser encontrada como material suplementario / a Spanish version of this paper can be found as supplementary material.

ecology↗