The Mycorrhizal Filter on Island Plant 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.
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 Island Plant Biogeography
Follow up work has shown 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 a Master's student to test whether the N-fixing filter is overcome by introduced naturalized plant species.
Linda Müller is leading this project. She's currently a Master's student at ETH Zurich. The conservation of natural ecosystems and biodiversity are very important to her. She wants to understand in what ways humans influence the environment and how negative human impacts can be minimised.
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Global island plant introductions
In this project we study the global patterns of island plant introductions of plants associating with nitrogen fixing bacteria. Using the Global Inventory of Floras and Traits (GIFT) and the Global Naturalized Alien Flora (GloNAF) database coupled with information on the species’ N-fixing status, we test which environmental factors drive the presence and proportion of naturalized N-fixing plant species on islands and compare it with native N-fixing plant species. In particular, we look at the dispersal filter, that was found for native N-fixing plants when colonizing islands, to see if naturalized N-fixing plants also experience this limitation. We aim to find out what determines islands to be colonized/endangered by naturalized N-fixing plants, to better understand human impact on island ecosystems. |