RESUMO
RESUMEN Los escarabajos coprófagos son excelentes indicadores de la integridad ecológica de los ecosistemas, cumpliendo un rol funcional esencial en el reciclaje de nutrientes, fertilización y aireación del suelo. Sin embargo, se conoce muy poco acerca de los ensambles de escarabajos altoandinos y de su estacionalidad. Por lo anterior, se buscó entender la variación estacional de la estructura del ensamble y su efecto en la biomasa, se escogieron dos pastizales, en la Reserva Biológica Encenillo (Guasca-Cundinamarca). En cada uno se dispusieron diez trampas de caída distanciadas 50 m y cebadas con excremento durante 24 horas. Se realizaron tres réplicas en cada una de las tres épocas estudiadas (seca, transición y lluvias). Se registró una variación estacional significativa, demostrando que las especies están asociadas a la época de lluvias. Se encontraron diferencias significativas para la biomasa entre especies y por época. La especie con la mayor biomasa fue Homocopris achamas. Se evidencia que los ensambles de pastizales altoandinos son poco diversos, debido a la fuerte perturbación antrópica, las presiones asociadas con la altitud y a la misma dinámica evolutiva de estas regiones. La marcada estacionalidad de las especies registradas y la estrecha asociación con la época de lluvias concuerda con el patrón estacional que se registra en el Neotrópico. La fuerte variación estacional de la biomasa puede tener un fuerte impacto en la funcionalidad ecológica y los servicios ecosistémicos en este hábitat. Es necesario cuantificar a futuro el aporte funcional de las especies y su variación estacional, con miras a su conservación.
ABSTRACT Dung beetles are excellent indicators of ecosystem ecological integrity, accomplishing an essential role in nutrient cycling process that includes fertilization and soil aeration. Nevertheless, very little is known about the influence of season variation on the assemblage composition and ecological function of dung beetles from high Andean zones. We aimed to investigate the seasonal effect on the diversity and ecological function of dung beetles in terms of biomass. We sampled two pasture patches of the "Reserva Biológica Encenillo", located in Cundinamarca-Colombia, using ten pitfall traps baited with feces placed 50 m apart for 24 hours. This sample design was replicated during each season (dry, transition, and rain). A significant seasonal variation was documented, demonstrating an important association with the rainy season. Significant differences were found for the biomass between species and seasons. The species with the highest biomass was Homocopris achamas. It is evident that high Andean pastures assemblages have low diversity, due to the strong human disturbance, the pressures associated with the altitude, and the evolutionary dynamics of these regions. The marked seasonality of the registered species and the close association with the rainy season are consistent with the pattern established for the Neotropical region. Likewise, a strong seasonal variation of the biomass is evident, which could have a significant impact on the ecological functionality and the ecosystem services in this habitat. In future studies, it is necessary to quantify the functional contribution of the species and their seasonal variation to contribute to their conservation.
RESUMO
Land-use change is one of the most important drivers of change in biodiversity. Deforestation for grazing or agriculture has transformed large areas of temperate forest in the central highlands of Mexico, but its impact on soil fungal communities is still largely unknown. In this study, we determined how deforestation of a high-altitude temperate forest for cultivation of maize (Zea mays L.) or husbandry altered the taxonomic, phylogenetic, functional, and beta diversity of soil fungal communities using a 18S rRNA metabarcoding analysis. The true taxonomic and phylogenetic diversity at order q = 1, i.e., considering frequent operational taxonomic units, decreased significantly in the arable, but not in the pasture soil. The beta diversity decreased in the order forest > pasture > arable soil. The ordination analysis showed a clear effect of intensity of land-use as the forest soil clustered closer to pasture than to the arable soil. The most abundant fungal phyla in the studied soils were Ascomycota, Basidiomycota, and Mucoromycota. Deforestation more than halved the relative abundance of Basidiomycota; mostly Agaricomycetes, such as Lactarius and Inocybe. The relative abundance of Glomeromycota decreased in the order pasture > forest > arable soil. Symbiotrophs, especially ectomycorrhizal fungi, were negatively affected by deforestation while pathotrophs, especially animal pathogens, were enriched in the pasture and arable soil. Ectomycorrhizal fungi were more abundant in the forest soil as they are usually associated with conifers. Arbuscular mycorrhizal fungi were more abundant in the pasture than in the arable soil as the higher plant diversity provided more suitable hosts. Changes in fungal communities resulting from land-use change can provide important information for soil management and the assessment of the environmental impact of deforestation and conversion of vulnerable ecosystems such as high-altitude temperate forests.