Investigating the Effects of Future Climate on Arbuscular Mycorrhizal Fungal Spore Dynamics in a Belgian Pear Orchard Ecosystem

Climate change poses a critical threat to both global natural and agricultural ecosystems, significantly affecting essential soil microbial communities, including arbuscular mycorrhizal fungi (AMF). These fungi form essential symbiotic relations with most terrestrial plant species, including economically significant ones such as fruit trees. As AMF are sensitive to climatic fluctuations, climate change influences AMF community species composition, diversity, ecological functions, and potentially even the temporal dynamics. Jointly this affects nature and temporal dynamics of AMF interactions with host plants. Although research has explored the impact of individual climate variables on AMF, a major knowledge gap remains in regard to how multiple climate parameters, exhibiting realistic climate change, simultaneously affect AMF community dynamics. This study aims to address this gap by examining the response of AMF to the worst-case climate change scenario (RCP8.5) forecasted for 2040. Using the state-of-the-art Ecotron facility, both ambient (2018) and future (2040) climate conditions were simulated for a pear orchard ecosystem, with six pear trees cultivated under each set of climatic conditions. We assessed climate change impact on AMF spore reproductive activity species composition (i.e., ratio intraradical over extraradical), and temporal dynamics, revealing patterns of dormancy and activity, and providing insights into the shifts in AMF community phenology induced by climate change. Our research advances the understanding of climate-driven dynamics of AMF in agricultural systems, providing insights into sustainable crop production and soil fertility under future climate conditions.