A test of community assembly rules using foliar endophytes from a tropical forest canopy

Community assembly theory assumes that ecological communities are spatially delimited into patches. Within these patches, coexistence results from environmental filtering, competition, and immigration. Truly delineated communities exist in laboratory studies of microbial cultures in Petri dishes, yet empirical tests conducted in continuous environments often use patches defined by convention as opposed to realised boundaries. Here we perform a test of ecological community assembly rules using foliar endophyte communities from a tropical rainforest, where leaves are considered as patches for both fungal and bacterial communities. We determined the diversity of fungal and bacterial endophytes using environmental DNA sequencing of 365 top-canopy leaves, collected from 38 host trees belonging to 22 different species across a 4-hectare research plot. Three leaves were collected from three or more branches within each tree crown. We tested the effect of host tree species and their level of ph...