Tree canopies represent the interface to the atmosphere and are exposed to the input ofenergy, water and matter. The leaf surfaces of trees roughly meets the Earth´s surface. Phyllosphere microbial communities in tree canopies perform central biogeochemical functions and interact with the host plant species in multiple ways.
Temporal and spatial heterogeneity of canopy microbial diversity is strongly influenced by phenology- driven changes of host plant properties but also by the structural heterogeneity of the tree canopy. We leverage the Leipzig Canopy Crane Facility of iDiv in a floodplain forest in Leipzig to disentangle the controls on canopy microbial diversity and functioning by analysing the relationship between microbial communities and microhabitat structure and chemical properties, and potential pathways of microbial distribution and nutrient supply within the canopy.
We hypothesize that vertical gradients of bacterial abundance and diversity across the canopy are tightly linked to throughfall-mediated vertical transfer of dust-, pollen- and leaf-derived carbon compounds and nutrients, and transport of microorganisms themselves. Further, we expect a strong correlation of temporal patterns of microbial communities and their predicted metabolic functions with phenology-driven changes of carbon compound and nutrient availability on leaf surfaces. In collaboration with iDiv researchers we integrate aspects of water and nutrient distributions within tree canopies as one key factor underlying spatial and temporal heterogeneity and provide a mechanistic explanation not only for microbial diversity patterns but also for distribution patterns of other taxonomic groups in tree canopies.