RESUMENEn este estudio se implementó el modelaje de distribución de especies para establecer el rango de distribución potencial de Podocnemis lewyana, explorar los componentes del clima que pueden influenciar dicha distribución y evaluar posibles fluctuaciones de su distribución bajo escenarios de clima futuro. Los modelos obtenidos predicen una distribución continua de sur a norte por todo el río Magdalena, desde los municipios de Rivera y Palermo en el departamento de Huila, hasta los departamentos de Atlántico y Magdalena en el norte. La temperatura fue el elemento del clima que más influyó en la distribución de P. lewyana; esta especie tiende a estar presente en climas cálidos y con poca variabilidad en la temperatura. El modelo de distribución transferido a los escenarios de clima futuro predicen un aumento en el rango geográfico de P. lewyana. Sin embargo, teniendo en cuenta las preferencias de hábitat de esta especie y su fuerte asociación con los cuerpos de agua, este resultado debe tomarse con cautela, dado que el modelo solo tuvo en cuenta variables climáticas terrestres. Dadas las características de historia de vida de esta especie (presencia de determinación sexual dependiente de la temperatura, alta temperatura pivotal y un rango de transición de temperatura muy estrecho), y el efecto negativo de los cambios en los regímenes hidrológicos en la mortalidad embrionaria, la expansión del área potencial de P. lewyana en el futuro no significa que esta especie no vaya a verse afectada por el cambio climático global.Palabras clave: Maxent, modelación de nicho, variables ambientales. ABSTRACTWe implemented a species distribution modelling approach to establish the potential distribution of Podocnemis lewyana, to explore the climatic factors that may influence the species' distribution and to evaluate possible changes in distribution under future climate scenarios. The distribution models predicted a continuous distribution from south to north along the Magdalena River, from Rivera and Palermo in the department of Huila to the departments of Atlántico and Magdalena in the north. Temperature was the variable most influential in the distribution of P. lewyana; this species tends to be present in warm regions with low temperature variability. The distribution model predicted an increase in the geographic range of P. lewyana under climate change scenarios. However, taking into account the habitat preferences of this species and its strong

Northwestern South America harbors one of the richest herpetofauna in the world. The connection among several biogeographic provinces along with climatic and orographic complexity makes this region an important contributor to the Neotropical biodiversity. Despite of this importance, the amphibian and reptile fauna in this area remains largely unknown as few herpetological collections has been made in recent decades. Motivated by this, the Herpetological Museum at the Universidad de Antioquia (Medellín, Colombia) has been increasing the collection in the last 16 years to better understand the herpetofaunal diversity and thus contribute to ecological, systematic, biogeographic and conservation research in the Neotropics. Here, we present the results of this effort and highlight how future collection will impact our understanding of the Neotropical herpetofauna.

Context The patch-mosaic model (PMM) is the most common way to describe the landscape in ecological research. Despite this, the gradient model (GM) was proposed as a more accurate representation of the heterogeneity of landscapes; however, little has been explored on the behavior and performance of continuous variables and surface-based metrics from GM under different analytical scenarios. Objectives We address the question: which landscape metrics, patch-based or surface-based, best explain habitat occupancy patterns of six bird species with different ecological preferences? Methods We generated detection histories for six bird species in a fragmented Andean landscape from Colombia. We obtain patch-based metrics from a land cover classification and surface-based metrics from the principal polar spectral indices (PPSi) to describe the landscape. Finally, we fitted dynamic occupancy models using variables derived from landscape models and compared their performance using quasi-AIC for each species. Results We obtained 909 detections for the six selected bird species. We found that PPSi and surface-based metrics were more informative when assessing occupancy patterns for five of the six species studied. In addition, surface-based metrics allowed to detect interspecific differences between species beyond an affinity for a particular cover type. Conclusions Surface-based metrics can be an alternative for assessing species response to landscape heterogeneity, particularly those that may be more sensitive to fine-scale changes in vegetation cover. However, there is no single “best” model to describe the landscape for all cases. PPSi can be very useful for land cover analysis in landscape ecology studies as an alternative to more popular vegetation indices.

Context: The patch-mosaic model (PMM) is the most common way to describe the landscape in ecological research. Despite this, the gradient model (GM) was proposed as a more accurate representation of the heterogeneity of landscapes; however, little has been explored on the behavior and performance of continuous variables and surface-based metrics from GM under different analytical scenarios.Objectives: We address the question: which landscape metrics, patch-based or surface-based, best explain habitat occupancy patterns of six bird species with different ecological preferences?Methods: We generated detection histories for six bird species in a fragmented Andean landscape from Colombia. We obtain patch-based metrics from a land cover classification and surface-based metrics from the principal polar spectral indices (PPSi) to describe the landscape. Finally, we fitted dynamic occupancy models using variables derived from landscape models and compared their performance using quasi-AIC for each species.Results: We obtained 909 detections for the six selected bird species. We found that PPSi and surface-based metrics were more informative when assessing occupancy patterns for five of the six species studied. In addition, surface-based metrics allowed to detect interspecific differences between species beyond an affinity for a particular cover type.Conclusions: Surface-based metrics can be an alternative for assessing species response to landscape heterogeneity, particularly those that may be more sensitive to fine-scale changes in vegetation cover. However, there is no single “best” model to describe the landscape for all cases. PPSi can be very useful for land cover analysis in landscape ecology studies as an alternative to more popular vegetation indices.