Does specialization lead to rarity? The distribution of mycoheterotrophic plants in relation to their mycorrhizal fungi
10 / 2011 - 10 / 2015
Mycoheterotrophic plants are achlorophyllous during their entire development and obtain all of their carbon from root-associated fungi. Most fully mycoheterotrophic flowering plants are growing in the leaf litter of dense tropical rain forest and associate with arbuscular mycorrhizal fungi (Glomeromycota). In contrast to autotrophic plants, some mycoheterotrophs are highly specialized on particular lineages of arbuscular mycorrhizal fungi. In the proposed study I will evaluate the role of mycorrhizal specialization in the distribution patterns of mycoheterotrophic species of Thismiaceae, Triuridaceae, and Voyria (Gentianaceae). The resulting biogeographical histories of these tropical groups coupled with observed mycorrhizal specialization trends will provide insights into the intriguing distribution patterns of these potentially ancient lineages. In turn, the obtained results will offer a new vantage point into the processes that shape plant communities in tropical rain forests in general. In the second part of this study I will infer how mycorrhizal specificity influences the local distribution of a plant species. This study will be focus on the mycoheterotroph and mycorrhizal specialist Thismia rodwayi (Thismiaceae) in Tasmania. Comparison of the arbuscular mycorrhizal fungus communities between Thismia and non-Thismia sites will address the potential correlation between the local distribution of the plant and that of its fungal associate. I will also be able to test whether Thismia rodwayi shows a preference towards mycorrhizal networks that include particular autotrophic plant species. The proposed study is the first to evaluate the local distribution of a rare mycorrhizal specialist in relation to the distribution of its fungal associate, and will offer valuable tools for the successful conservation of plants that show specificity in their mycorrhizal interactions.