Biology subjects

Merloti, L. F.

Publications and source records attributed to Merloti, L. F..

2 recordsLinked to original sources

bioRxiv2025

Connectivity of restored Atlantic Forest fragments drives composition and functionality of the fungal community in the leaf litter layer

The restoration of biodiversity and functional tropical forests is critical to mitigating global biodiversity losses. Aboveground, increasing the connectivity of regenerating forests fragments facilitates the recolonization of tropical forest biodiversity. However, restoring functional ecosystems also requires the recovery of decomposition processes as these are essential in shaping aboveground biodiversity. Therefore, we investigate the role of forest connectivity on restoring the composition and functioning of fungal communities in the leaf litter layer during a chronosequence of forest restoration. In the Brazilian Atlantic Forest, we studied secondary forests regrown between 18 to 55 years after deforestation and different levels of forest connectivity and compared their litter to recently abandoned pastures and undisturbed primary forests. We quantified how forest age and connectivity between fragments influenced the litter fungi composition in relation to tree diversity, litter chemistry, and litter isotopes. We show that fungal composition was highly heterogeneous in forest litter, whereas pasture litter exhibited a more homogeneous community. Moreover, forest connectivity had stronger effects on litter fungal composition compared to forest age. Connectivity promoted wood saprotrophs and endophytes, while suppressed soil saprotrophs, with its effects being more evident during later stages of restoration. Fungal guilds such as endophytes and saprophytes, were primarily influenced by tree diversity and leaf litter chemistry. We conclude that forest connectivity promotes the re-establishment of saprophytic fungi capable of decomposing recalcitrant litter substrates, driven mainly by enhancing tree diversity and litter quality. Practical implications of increasing connectivity may relate to forest resilience on front of future climate change scenarios.

microbiology↗

bioRxiv2021

Maintaining grass coverage increases methane uptake in Amazonian pasture soils

Cattle ranching is the largest driver of deforestation in the Brazilian Amazon. The rainforest- to-pasture conversion affects the methane cycle in upland soils, changing it from sink to source of atmospheric methane. However, it remains unknown if management practices could reduce the impact of land-use on methane cycling. In this work, we evaluated how pasture management can regulate the soil methane cycle either by maintaining continuous grass coverage on pasture soils, or by liming the soil to amend acidity. Methane fluxes from forest and pasture soils were evaluated in moisture-controlled greenhouse experiments with and without grass cover (Urochloa brizantha cv. Marandu) or liming. In parallel, we assessed changes in the soil microbial community structure of both bare pasture soil as well as rhizosphere soil through high throughput sequencing of the 16S rRNA gene, and quantified the methane cycling microbiota by their respective marker genes related to methane generation (mcrA) or oxidation (pmoA). The experiments used soils from eastern and western Amazonia, and concurrent field studies allowed us to confirm greenhouse data. The presence of a grass cover not only increased methane uptake by up to 35% in pasture soils, but also reduced the abundance of the methane-producing community. In the grass rhizosphere this reduction was up to 10-fold. Methane-producing archaea belonged to the genera Methanosarcina sp., Methanocella sp., Methanobacterium sp., and Rice Cluster I. Further, we showed that liming compromised the capacity of forest and pasture soils to be a sink for methane, and instead converted formerly methane-consuming forest soils to become methane sources in only 40-80 days. Our results demonstrate that pasture management that maintains grass coverage can mitigate soil methane emissions, if compared to a bare pasture soil.

microbiology↗