Woody encroachment, that is, the increase in density of indigenous woody cover within grassy ecosystems, is a major concern globally (Archer et al., 2017). Associated changes in tree-grass ratios modify the composition of ecological communities (Ratajczak et al., 2012) and the provision of ecosystem services (Asner et al., 2004) and is thought to be the result of a combination of both local (e.g., changes in fire and herbivory management) and global (e.g., increased atmospheric carbon dioxide concentrations) drivers (Skowno et al., 2017; Wigley et al., 2010). Although encroachment is generally viewed as the densification of woody species, it can also occur through the formation of bush clumps (i.e., dense clumps of woody species) which subsequently expand in size (O'Connor & Chamane, 2012). This succession often starts with the establishment of a founder tree which then

No abstract

Patterns and drivers of succession provide insight into the mechanisms that govern community assembly and are indicators of community resilience and stability but are still poorly understood in microbial communities. We assessed whether the successional trends of woody vegetation are mirrored by foliar fungal endophyte communities of three tree species that are abundant across the woody successional gradient using a total amplicon sequencing approach. Additionally, we test the relative contribution of host identity, abiotic predictors, biotic factors, and spatial distance between sites in predicting community composition and species richness of endophyte communities. Unlike the woody community, endophyte communities showed no consistent evidence of deterministic successional trends. Host identity was the most important factor structuring fungal endophyte community composition. Spatial distance played some role in explaining differences in community composition, but the effects of this and other environmental variables were small and not consistent between different host species. Much of the variation in endophyte composition remained unexplained. Host identity was most important in predicting endophyte richness. Although endophyte communities showed no deterministic succession, community assembly was most strongly influenced by host identity and spatial distance.

No abstract

No abstract