Abstract
Microbes, similar to plants and animals, exhibit biogeographic patterns. However, in contrast with the considerable knowledge on the island biogeography of higher organisms, we know little about the distribution of microorganisms within and among islands. Here, we explored insular soil bacterial and fungal biogeography and underlying mechanisms, using soil microbiota from a group of land-bridge islands as a model system. Similar to island species-area relationships observed for many macroorganisms, both island-scale bacterial and fungal diversity increased with island area; neither diversity, however, was affected by island isolation. By contrast, bacterial and fungal communities exhibited strikingly different assembly patterns within islands. The loss of bacterial diversity on smaller islands was driven primarily by the systematic decline of diversity within samples, whereas the loss of fungal diversity on smaller islands was driven primarily by the homogenization of community composition among samples. Lower soil moisture limited within-sample bacterial diversity, whereas smaller spatial distances among samples restricted among-sample fungal diversity, on smaller islands. These results indicate that among-island differences in habitat quality generate the bacterial island species-area relationship, whereas within-island dispersal limitation generates the fungal island species-area relationship. Together, our study suggests that different mechanisms underlie similar island biogeography patterns of soil bacteria and fungi.
Highlights
Islands have served as useful natural laboratories for addressing fundamental ecological and evolutionary questions [1,2,3]
To our knowledge, the first empirical evidence that soil bacteria and fungi on islands exhibited similar island-scale biogeographic patterns, but that these similar patterns were driven by strikingly different mechanisms
This pattern appears to be in line with the prediction of the area per se effect, which suggests that higher alpha diversity on larger islands can be driven by a neutral equilibrium between species immigration and extinction, as postulated by the theory of island biogeography [4]
Summary
Beta diversity of soil bacteria and fungi within islands, as well as the relative importance of environmental and spatial factors for these diversity components, we aimed to unravel mechanisms underlying the biogeography of soil microbes on these islands
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have