Replacing low-intensity cattle pasture with oil palm conserves dung beetle functional diversity when paired with forest protection.

Meeting rising demand for oil palm whilst minimizing the loss of tropical biodiversity and associated ecosystem functions is a core conservation challenge. One potential solution is focusing the expansion of high-yielding crops on presently low-yielding farmlands alongside protecting nearby tropical forests that can enhance provision of ecosystem functions. A key question is how this solution would impact invertebrate functional diversity. We focus on oil palm in the Colombian Llanos, where plantations are replacing improved cattle pastures and forest fragments, and on dung beetles, which play key functional roles in nutrient cycling and secondary seed dispersal. We show that functional richness and functional diversity of dung beetles is greater in oil palm than in cattle pasture, and that functional metrics did not differ between oil palm and remnant forest. The abundance-size class profile of dung beetles in oil palm was more similar to forest than to pasture, which had lower abundances of the smallest and largest dung beetles. The abundance of tunneling and rolling dung beetles did not differ between oil palm and forest, while higher forest cover increased the abundance of diurnal and generalist-feeding beetles in oil palm landscapes. This suggests that prioritizing agricultural development on low-yielding cattle pasture will have positive effects on functional diversity and highlights the need for forest protection to maintain ecosystem functioning within agricultural landscapes.

Thermal tolerance and the importance of microhabitats for Andean frogs in the context of land use and climate change.

Global warming is having impacts across the Tree of Life. Understanding species' physiological sensitivity to temperature change and how they relate to local temperature variation in their habitats is crucial to determining vulnerability to global warming. We ask how species' vulnerability varies across habitats and elevations, and how climatically buffered microhabitats can contribute to reduce their vulnerability. We measured thermal sensitivity (critical thermal maximum-CTmax ) of 14 species of Pristimantis frogs inhabiting young and old secondary, and primary forests in the Colombian Andes. Exposure to temperature stress was measured by recording temperature in the understorey and across five microhabitats. We determined frogs' current vulnerability across habitats, elevations and microhabitats accounting for phylogeny and then ask how vulnerability varies under four warming scenarios: +1.5, +2, +3 and +5°C. We found that CTmax was constant across species regardless of habitat and elevation. However, species in young secondary forests are expected to become more vulnerable because of increased exposure to higher temperatures. Microhabitat variation could enable species to persist within their thermal temperature range as long as regional temperatures do not surpass +2°C. The effectiveness of microhabitat buffering decreases with a 2-3°C increase, and is almost null under a 5°C temperature increase. Microhabitats will provide thermal protection to Andean frog communities from climate change by enabling tracking of suitable climates through short distance movement. Conservation strategies, such as managing landscapes by preserving primary forests and allowing regrowth and reconnection of secondary forest would offer thermally buffered microhabitats and aid in the survival of this group.

Para determinar la vulnerabilidad de las especies al calentamiento global es indispensable considerar la tolerancia fisiológica de las especies al cambio de temperatura y las condiciones ambientales a las que están expuestas. En este estudio exploramos la vulnerabilidad de especies a través de diferentes hábitats y altitudes y examinamos si ciertos microhábitats contribuyen a reducir la vulnerabilidad al calentamiento global. Medimos la tolerancia térmica (CTmax ) de catorce especies de ranas Pristimantis en bosques secundarios jóvenes y viejos, y bosques primarios en los Andes tropicales. Registramos la temperatura a la que estas especies están expuestas en el sotobosque así como dentro de cinco microhábitats. Usando CTmax y las temperaturas a las que están expuestas, determinamos la vulnerabilidad de las especies en diferentes hábitats, elevaciones y microhábitats. También preguntamos cómo cambiará esta vulnerabilidad si la temperatura incrementa: 1.5°C, 2°C, 3°C y 5°C. CTmax fue constante en todos los hábitats y elevaciones. Las especies de bosques secundarios jóvenes son más vulnerables pues están expuestas a temperaturas más altas. Al utilizar microhábitats, las especies estarán protegidas si el aumento de temperatura no supera los + 2°C. Todos los microhábitats seguirán proporcionando refugio térmico si la temperatura aumenta 1.5°C, pero esta protección térmica disminuirá si la temperatura aumenta 2-3°C y será casi nula con un aumento de temperatura de 5°C. Los microhábitats proporcionarán protección térmica a la comunidad de ranas de los Andes contra el cambio climático. Estrategias de conservación, como la regeneración natural y la reconexión de bosques secundarios y la preservación de bosques primarios, ayudaría a la supervivencia de las ranas al tener microhábitats que ofrecen refugio térmico.

Minimizing the biodiversity impact of Neotropical oil palm development.

Oil palm agriculture is rapidly expanding in the Neotropics, at the expense of a range of natural and seminatural habitats. A key question is how this expansion should be managed to reduce negative impacts on biodiversity. Focusing on the Llanos of Colombia, a mixed grassland-forest system identified as a priority zone for future oil palm development, we survey communities of ants, dung beetles, birds and herpetofauna occurring in oil palm plantations and the other principal form of agriculture in the region--improved cattle pasture--together with those of surrounding natural forests. We show that oil palm plantations have similar or higher species richness across all four taxonomic groups than improved pasture. For dung beetles, species richness in oil palm was equal to that of forest, whereas the other three taxa had highest species richness in forests. Hierarchical modelling of species occupancy probabilities indicated that oil palm plantations supported a higher proportion of species characteristic of forests than did cattle pastures. Across the bird community, occupancy probabilities within oil palm were positively influenced by increasing forest cover in a surrounding 250 m radius, whereas surrounding forest cover did not strongly influence the occurrence of other taxonomic groups in oil palm. Overall, our results suggest that the conversion of existing improved pastures to oil palm has limited negative impacts on biodiversity. As such, existing cattle pastures of the Colombian Llanos could offer a key opportunity to meet governmental targets for oil palm development without incurring significant biodiversity costs. Our results also highlight the value of preserving remnant forests within these agricultural landscapes, protecting high biodiversity and exporting avian 'spill-over' effects into oil palm plantations.

Effect of scale on trait predictors of species responses to agriculture.

Species persistence in human-altered landscapes can depend on factors operating at multiple spatial scales. To understand anthropogenic impacts on biodiversity, it is useful to examine relationships between species traits and their responses to land-use change. A key knowledge gap concerns whether these relationships vary depending on the scale of response under consideration. We examined how local- and large-scale habitat variables influence the occupancy dynamics of a bird community in cloud forest zones in the Colombian Chocó-Andes. Using data collected across a continuum of forest and agriculture, we examined which traits best predict species responses to local variation in farmland and which traits best predict species responses to isolation from contiguous forest. Global range size was a strong predictor of species responses to agriculture at both scales; widespread species were less likely to decline as local habitat cover decreased and as distance from forest increased. Habitat specialization was a strong predictor of species responses only at the local scale. Open-habitat species were particularly likely to increase as pasture increased, but they were relatively insensitive to variation in distance to forest. Foraging plasticity and flocking behavior were strong predictors of species responses to distance from forest, but not their responses to local habitat. Species with lower plasticity in foraging behaviors and obligate flock-following species were more likely to decline as distance from contiguous forest increased. For species exhibiting these latter traits, persistence in tropical landscapes may depend on the protection of larger contiguous blocks of forest, rather than the integration of smaller-scale woodland areas within farmland. Species listed as threatened or near threatened on the International Union for Conservation of Nature Red List were also more likely to decline in response to both local habitat quality and isolation from forest relative to least-concern species, underlining the importance of contiguous forests for threatened taxa.

Optimizing carbon storage and biodiversity protection in tropical agricultural landscapes.

With the rapidly expanding ecological footprint of agriculture, the design of farmed landscapes will play an increasingly important role for both carbon storage and biodiversity protection. Carbon and biodiversity can be enhanced by integrating natural habitats into agricultural lands, but a key question is whether benefits are maximized by including many small features throughout the landscape ('land-sharing' agriculture) or a few large contiguous blocks alongside intensive farmland ('land-sparing' agriculture). In this study, we are the first to integrate carbon storage alongside multi-taxa biodiversity assessments to compare land-sparing and land-sharing frameworks. We do so by sampling carbon stocks and biodiversity (birds and dung beetles) in landscapes containing agriculture and forest within the Colombian Chocó-Andes, a zone of high global conservation priority. We show that woodland fragments embedded within a matrix of cattle pasture hold less carbon per unit area than contiguous primary or advanced secondary forests (>15 years). Farmland sites also support less diverse bird and dung beetle communities than contiguous forests, even when farmland retains high levels of woodland habitat cover. Landscape simulations based on these data suggest that land-sparing strategies would be more beneficial for both carbon storage and biodiversity than land-sharing strategies across a range of production levels. Biodiversity benefits of land-sparing are predicted to be similar whether spared lands protect primary or advanced secondary forests, owing to the close similarity of bird and dung beetle communities between the two forest classes. Land-sparing schemes that encourage the protection and regeneration of natural forest blocks thus provide a synergy between carbon and biodiversity conservation, and represent a promising strategy for reducing the negative impacts of agriculture on tropical ecosystems. However, further studies examining a wider range of ecosystem services will be necessary to fully understand the links between land-allocation strategies and long-term ecosystem service provision.

Passive acoustic sampling data of the Colección de Sonidos Ambientales Mauricio Álvarez-Rebolledo - Instituto Humboldt (IAvH-CSA) during 2018 and 2019 in Colombia.

We present the dataset of passive acoustic sampling events deposited in the Colección de Sonidos Ambientales Mauricio Álvarez-Rebolledo at the Humboldt Institute (IAvH-CSA) during the years 2018-2019. The acoustic sampling events were generated from different projects, including Colombia Bio, Santander Bio, Boyacá Bio, Lisama, Riqueza Natural, and occasional events collected during this time. In total, 44,704 sampling events are deposited in the collection, corresponding to 1 minute of automatic recording sampled at a 44.1 kHz sampling rate and 16-bit resolution. The recording schedules correspond to 1 minute every 5, 10, or 30 min throughout the day, during 1 to 20 sampling days, across 79 localities in Colombia. The geographical coverage includes the departments of Bolívar, Boyacá, Caquetá, Cundinamarca, Meta, Santander, and Sucre. The present information was collected within the framework of the passive monitoring methodology established by the Humboldt Institute .