Beyond seasonal and host factors: ecosystem dynamics drive palm-associated root fungal communities at a local scale

Background and Aims: The increase of extreme weather events due to climate change may alter ecosystem dynamics. In the tropics, little is known about how ecosystems and species will respond to droughts or floods. Identifying the most important biotic and abiotic factors in ecosystems at the local level is key to developing better forest management practices and understanding the effects of climate change on the fungal community. Methods: We conducted a random sampling of adult individuals from several palm species across three adjacent ecosystems with different hydrological conditions, during rainy and dry seasons. Using next-generation sequencing, we identified fungal communities and determined the influence of soil physicochemical properties, as well as host and seasonal variables, on the relative abundance of the root- and rhizosphere-associated fungal communities. Results: The composition of the fungal communities was similar between the seasonally flooded forest and the terra-firme forest, while the palm swamp diverged due to differences in soil physicochemical properties. Seasonal analyses revealed significant differences in the relative abundance of several taxa, mainly associated with the seasonally flooded forest. However, no influence of palm species on fungal abundance was detected at any taxonomic level. Conclusion: This study highlights the importance of studying ecosystems at the local scale and considering ecosystem dynamics into the study of fungal communities and other microorganisms. Such an approach is crucial for improving predictions under climate change scenarios and understanding the consequences of altering these dynamics in vulnerable, often understudied ecosystems.