The Effect of the Conversion from Natural Broadleaved Forests into Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) Plantations on Soil Microbial Communities and Nitrogen Functional Genes

Large-scale sampling of beetle communities in Laos shows that conversion of natural forests into plantations leads to a decline in family richness and abundance

Rapid economic development can pose a threat to the biodiversity of tropical countries. In Laos, this is manifested by the conversion of natural forests into plantations, even though this area is one of the biodiversity hotspots of Southeast Asia. Beetle communities can be good indicators of the impact of anthropogenic pressure on natural ecosystems. In this study, we analyzed for the first time a large-scale inventory of Coleoptera to assess the ecological and anthropogenic drivers of beetle communities in Laos. We examined beetle communities (described at the family level) across the country, located in distinct habitat types, in order to understand the impact of the conversion of natural forest into plantations. We found that beetle abundance had declined in plantations compared to natural forests. At the same time, we observed fewer beetle families in plantations overall, but at the scale of sampling sites there was no difference in local richness compared to natural forests, suggesting a homogenization of beetle communities in anthropogenic habitats. Although results are certainly sensitive to our coarse classification of beetle specimens into families, the negative impact of the conversion of natural tropical forests into agriculture area can still be clearly demonstrated. Our findings highlight that it is possible to make use of unstructured large-scale inventories to explore how beetle communities responds to landscape changes induced by human activities. We suggest that sampling beetle communities can be used as an ecological indicator to monitor anthropogenic impacts on tropical ecosystems.

Fungi Present in the Organic and Mineral Layers of Six Broad-Leaved Tree Plantations as Assessed by the Plate Dilution Method

This study examined the distribution of culturable fungi and predominant genera in the organic layer and in the upper layers of the mineral soil of six broad-leaved tree plantations in autumn, after the full fall of leaves. In total, 1335 fungal isolates were recovered from an organic layer and two mineral layers (0–4 cm and 5–8 cm) of soil. The structure of fungal genera differed in the tree plantations and in the three studied soil layers. The organic layer was the layer most populated by fungi compared to the mineral layers. In the organic layer, Penicillium and phyllosphere fungi such as Cladosporium and Phoma dominated. Deeper in the soil, the dominance of certain genera decreased with the increase in Trichoderma, Mucor, Mortierella, and entomopathogenic fungi such as Paecilomyces and Beauveria. Penicillium was one of the most abundant fungi in all soil layers studied.