The Mycorrhizal Filter on plant island biogeography
Classical island plant biogeography has predominantly focused on abiotic drivers of plant distributions, but has excluded interacting organisms that play a key role in influencing plant establishment. We found that establishment of plants on islands is limited by mycorrhizal fungi, particularly dispersal limited AM fungi. In addition, human introduction of plant species erased this initial mycorrhizal filter. This work also tested for consequences of this initial filter to plant diversification by looking at endemic plant species on islands, with the initial filtering out of AM plant species on islands gives way to an increased diversification of AM plant species. This work shows that long ignored biotic interactions between plants and mycorrhizal fungi determine global plant biogeography, shifting the longstanding abiotic centric perspective in island biogeography to include plant-associated mutualists, with practical implications for more informed and improved management and restoration of island sites.
The N-fixing filter on plant Island Biogeography
Follow up work has showed that there is an analogous filter on N-fixing plant species, with N-fixing plant species underrepresented on islands worldwide. This has important implications for both ecosystem development and risks from introduction of N-fixing plant species. Currently, I am collaborating with an undergraduate student to test whether the N-fixing filter is overcome by introduced naturalized plant species.