Interactions with soil fungi alter density-dependence and neighborhood effects in a locally abundant dipterocarp species

Seedling recruitment can be strongly affected by the composition of nearby plant species. At the neighborhood scale (on the order of tens of meters), adult conspecifics can modify soil chemistry and presence of host microbes (pathogens and mutualists) across their combined canopy area or rooting zones. At local or small spatial scales (on the order of one to few meters), conspecific seed or seedling density can influence the strength of intraspecific light and resource competition and also modify the density-dependent spread of natural enemies such as pathogens or invertebrate predators. Intrinsic correlation between proximity to adult conspecifics (i.e. recruitment neighborhood) and local seedling density, arising from dispersal, make it difficult to separate the independent and interactive factors that contribute to recruitment success. 

Here, we present a field experiment in which we manipulated both the recruitment neighborhood and seedling density to explore how they interact to...