Data from: Evolution of a key trait greatly affects underground community assembly process through habitat adaptation in earthworms

Underground community assemblies have not been studied well compared with
aboveground communities, despite their importance for our understanding of
whole ecosystems. To investigate underground community assembly over
evolutionary time scales, we examined terrestrial earthworm communities
(Oligochaeta: Haplotaxida) in conserved mountainous primary forests in
Japan as a model system. We collected 553 earthworms mostly from two
dominant families, the Megascolecidae and the Lumbricidae, from 12 sites.
We constructed a molecular taxonomic unit tree based on the analysis of
three genes to examine the effects of a biogeographic factor (dispersal
ability) and an evolutionary factor (habitat adaptation) on the earthworm
community assembly process. The phylogenetic distance of the earthworm
communities among sites was positively correlated with geographic distance
when intraspecific variation was included, indicating that the divergence
within species was affected by biogeographic factors. The community
assembly process in the Megascolecidae has also been affected by
environmental conditions in relation to an evolutionary relationship
between habitat environment and intestinal caecum type, a trait closely
related to habitat depth and diet, whereas that in the Lumbricidae has not
been affected as such. Intestinal caecum type showed a pattern of niche
conservatism in the Megascolecidae lineage. Our results suggest that
investigating the evolution of a key trait related to life history can
lead to the clear description of community assembly process over a long
time scale and that the community assembly process can differ greatly
among related lineages even though they live sympatrically.