Data from: Host associations and beta diversity of fungal endophyte communities in New Guinea rainforest trees

Processes shaping the distribution of foliar fungal endophyte species
remain poorly understood. Despite increasing evidence that these cryptic
fungal symbionts of plants mediate interactions with pathogens and
herbivores, there remain basic questions regarding the extent to which
dispersal limitation and host specificity might shape fungal endophyte
community composition in rainforests. To assess the relative importance of
spatial pattern and host specificity, we isolated fungi from a sample of
mapped trees in lowland Papua New Guinea. Sequences of the internal
transcribed spacer (ITS) region were obtained for 2,079 fungal endophytes
from three sites and clustered into molecular operational taxonomic units
(MOTUs) at 95% similarity. Multivariate analyses suggest that host
affinity plays a significant role in structuring endophyte community
composition whereas there was no evidence of endophyte spatial pattern at
the scale of tens to hundreds of meters. Differences in endophyte
communities between sampled trees were weakly correlated with variation in
foliar traits but not with tree species relatedness. The dominance of
relatively few generalist endophytes and the presence of a large number of
rare MOTUs was a consistent observation at three sites separated by
hundreds of kilometers and regional turnover was low. Host specificity
appears to play a relatively weak but more important role than dispersal
limitation in shaping the distribution of fungal endophyte communities in
New Guinea forests. Our results suggest that in the absence of strong
ecological gradients and host turnover, beta diversity of endophyte
communities could be low in large areas of contiguous forest.