Orlando Fabián Hernández-Leal

A central quest in conservation biology is to understand how wildlife responds to human-modified landscapes. Yet assessing features of transformed landscapes is non-trivial because categorical maps obscure ecologically meaningful transitions that organisms perceive continuously. We overcame this limitation by using satellite-based fine-scale continuous measures of landscape structure to examine how the cover, complexity, distribution and isolation of exposed and forested areas influence the composition of two guild of aerial insectivorous bats across multiple spatial scales. Although insectivorous bats provide key ecosystem services, it is still unclear which landscape features favor or reduce their abundance, and at what scales these effects occur. Our study was conducted in a heterogeneous agricultural mosaic in the central Andes of Colombia, ranging from well-preserved forests to open-pit mines. Bats that forage within forests or along edges were more abundant at sites with more forest cover but also where vegetation was more complex in terms of roughness and the presence of edges across all spatial scales. Contrary to our predictions, bats that forage in open spaces decreased in areas where exposed lands and fragments were dispersed and isolated at small spatial scales. At large spatial scales, open-space bats required abundant forest cover. These results show that insectivorous bats respond differently to landscape change depending on their ecology and movement behavior, and that these responses vary with spatial scale. Our findings highlight the value of using continuous landscape measures to better understand, manage, and conserve insectivorous bats in regions undergoing rapid land-use change.

A central challenge in bat ecology is to determine how and why functional diversity changes in anthropogenically modified environments. Recognizing which factors alter functional diversity after land-use change can steer management plans to preserve functionally diverse communities. Here we used a novel approach using satellite-based fine-scale continuous measures of landscape structure to explore whether cover, complexity, distribution and isolation of vegetated and exposed surfaces areas explain the functional diversity of two groups of aerial insectivorous bats at three spatial scales within an agricultural matrix in central Colombia. First, we found that open space species occupied a broader functional trait space and were more functionally diverse than forest species. Second, average vegetation cover and forest patch continuity and contiguity explained functional divergence of forest species. Similarly, the average amount of unvegetated areas explained the functional divergence of open space species. Other measures of functional diversity (richness, evenness and quadratic entropy) of both functional groups, however, remained unexplained. Third, functional divergence of forest and open space bats were explained by landscape cover at the smallest and largest spatial scales, respectively. We conclude that matrices composed of large and contiguous forest fragments intermixed with pastures and crops promote the coexistence of abundant species with contrasting morphologies and echolocation behaviors from both functional groups. Management should bring about these types of landscapes. Linking continuous metrics of landscape structure derived from remote sensing with functional diversity offers powerful new tools for monitoring multiple dimensions of bat diversity.

As agriculture continues to expand in tropical regions, effectively preserving biodiversity will rely not only on protected areas but also on sustainable practices within agricultural landscapes. Studying biodiversity changes associated with landscape management is essential for refining practices that support ecosystem resilience and species conservation, but collecting the data required to draw strong conclusions remains challenging because of the high spatial and temporal resolution needed. In this context, passive acoustic monitoring (PAM) offers a valuable solution by enabling researchers to gather continuous, high-resolution biotic signals over time. Using PAM, our objective was to examine how changes in landscape characteristics, specifically heterogeneity and composition, correlate with soundscape patterns including acoustic activity and beta diversity. We collected data across 52 000 ha in the Magdalena River Valley, Colombia, a biodiversity hotspot significantly transformed by palm oil monocultures. We contrasted soundscape data, including acoustic activity and soundscape turnover, with landscape metrics derived from Geographical Information Systems analysed satellite imagery, focusing on landscape composition and configuration. Our analysis showed that compositional and heterogeneity-related landscape variables, such as the proportion of natural cover (NC) and patch shape, were associated with differences in acoustic activity and soundscape homogenization. Specifically, patches with uniform shapes and a lower NC correspond to more homogeneous soundscapes with higher acoustic activity. In contrast, patches with irregular shapes and a higher NC were linked to more heterogeneous soundscapes and lower acoustic activity. By linking soundscape patterns with landscape metrics, we highlight the importance of retaining natural habitat features within productive areas to support acoustic diversity, and by extension, ecological resilience. This article is part of the theme issue ‘Acoustic monitoring for tropical ecology and conservation’.

Diet and foraging studies in birds are essential for a comprehensive understanding of the transport of matter and energy in aquatic ecosystems. The use of passive methods has been suggested as a tool to identify the diet of birds. Based on the use of camera traps we report new food items for herons Tigrisoma lineatum, Ardea cocoi and Ardea alba in the Middle Magdalena Valley, Colombia. Camera traps function as a complementary tool for deciphering food items in waterbirds foraging at the edge of water bodies. They contribute considerably to the natural history of bird, fish and reptile species as well as to predatory behaviors, dietary relationships and their functional role within an ecosystem.

Insectivorous bats of the genus Pteronotus are considered rare or uncommon because they are difficult to capture with traditional methods (i.e., mist nets and harp traps). However, these bats have distinct echolocation call design that enables their detection and recognition acoustically. In this note, we report the presence of 3 species of bats of the Pteronotus genus from acoustic records in the department of Vichada in Colombia and we present a brief characterization of the echolocation calls for each species. We conducted passive acoustic monitoring in 3 localities and analyzed echolocation calls of sequences. Additionally, we searched for bat capture records in biological collections and scientific articles to find out the current distribution of the Pteronotus genus in Colombia. We recorded 3 species of bats of the Pteronotus genus: P. personatus, P. gymnonotus, and P. cf. rubiginosus. As for the search of records in biological collections and articles, we found that 8 out of 59 records of Pteronotus species in Colombia were from Vichada department. This work provides evidence that acoustic surveys for bats efficiently register elusive and difficult-to-capture insectivorous species, such as those of the genus Pteronotus.

Neotropical fruit bats of the genus Carollia consume the infructescences of native Piper species. Black pepper, Piper nigrum, a species exotic to the Neotropics, has been planted in several countries of Latin America. Black pepper has been reported as a frequent item in the diet of C. brevicauda and also has found in the diet of C. perspicillata. Essential oils of Neotropical Piper species may attract Carollia bats, and probably increase the value of food containing them. However, since black pepper is originally from Asia, its essential oils may act as chemical defenses against non-dispersers such as the Neotropical fruit bats. Therefore, we used the giving-up density technique (GUD), to evaluate the effect of the essential oils of black pepper in food on the foraging behavior of C. perspicillata. We offered captive male bats artificial food with and without the essential oils of P. nigrum and measured their GUDs. The addition of the essential oils of P. nigrum greatly increased the bats’ GUD, indicating that male C. perspicillata treated such secondary metabolites as toxins.

La bioacústica permite monitorear murciélagos difícilmente detectados con métodos tradicionales, como las redes de niebla, y permiten obtener información sobre diferentes aspectos de la biología de las especies de estudio. En los últimos años se ha incrementado el interés por la aplicación de estos métodos y, en consecuencia, ha sido rápido el desarrollo de los equipos de grabación ultrasónica y las herramientas de análisis. Sin embargo, en el Neotrópico la bioacústica de murciélagos está en etapa de crecimiento en algunos países y apenas ahora está apareciendo en otros, por lo cual es necesario fortalecer este campo para estudiar la alta diversidad taxonómica y funcional de la región. En este contexto, es indispensable contar con bibliotecas de señales acústicas, que sirvan como referencia para identificar, validar y comparar las grabaciones de diferentes especies y localidades. Algunos países del Neotrópico han avanzado en este proceso y están construyendo estas bibliotecas de referencia. En Colombia, el trabajo a futuro implica un reto, debido a las más de 200 especies de murciélagos presentes. Este trabajo presenta las bases metodológicas para tomar grabaciones de referencia de murciélagos en Colombia y generar una guía para aquellos que se están iniciando en este campo de investigación.

La ganadería en el piedemonte llanero colombiano está ampliamente distribuida y se desconoce su impacto sobre los murciélagos insectívoros aéreos. Monitoreamos por métodos acústicos pasivos a estos murciélagos en un sistema silvopastoril (SSP) plantado con Mimosa trianae, un sistema ganadero convencional dominado por pasto (SC) y un bosque (B) en el piedemonte llanero colombiano. La composición de especies del B se diferenció de las otras coberturas, mientras que no hubo diferencias entre SC y SSP. Hubo mayor riqueza en el SC que en las otras coberturas, mientras que no hubo diferencias entre el B y el SSP. Myotis nigricans, Peropteryx macrotis, Saccopteryx leptura, Molossus cf. rufus, Eptesicus I y Cormura brevirostris tuvieron la mayor actividad en el paisaje, y su uso del espacio dependió de la cobertura. La mayoría de las especies usaron el SC más que las otras coberturas. En conclusión, la heterogeneidad espacial asociada al paisaje ganadero estudiado tiene efectos tanto en la estructura del ensamble como en las respuestas de las especies que lo conforman.

La Colección Mastozoológica del Museo de Historia Natural-Unillanos (MHNU-M) alberga en el momento 422 especímenes pertenecientes a ocho órdenes, 16 familias, 46 géneros, y 66 especies. Los especímenes provienen de cinco departamentos de Colombia, principalmente de la región de la Orinoquía. El número de especímenes de la Colección se ha enriquecido con actividades académicas de la Universidad de los Llanos, tesis de pre y posgrado, convenios y proyectos de investigación.