Data from: Ecological drift and local exposures drive gastrointestinal bacterial community differences among Galápagos iguana populations

Diet strongly influences the intestinal microbial communities through
species sorting. Alternatively, these communicates may differ because of
chance variation in local microbial exposures or species losses among
allopatric host populations (i.e. ecological drift). We investigated how
these forces shape enteric communities of Galápagos marine and land
iguanas. Geographically proximate populations shared more similar
communities within a host ecotype, suggesting a role for ecological drift
during host colonization of the islands. Additionally, evidence of taxa
sharing between proximate heterospecific host populations suggests that
contemporary local exposures also influence the gut community assembly.
While selective forces such as host-bacterial interactions or dietary
differences are dominant drivers of intestinal community differences among
hosts, historical and contemporary processes of ecological drift may lead
to differences in bacterial composition within a host species. Whether
such differences in community structure translate into geographic
variation in benefits derived from these intimate microbial communities
remains to be explored.