Hanna Tuomisto is broadly interested in ecology and biogeography of tropical forests. She has carried out extensive fieldwork in different parts of tropical America, especially Amazonia, to document plant–soil relationships, spatial variation in plant community composition, and bio- geographical patterns across the tropical rainforest biome.

To be able to sample megadiverse forests over an entire continent, Tuomisto has applied and refined the indicator species approach. This means that instead of inventorying all plants, the research focuses on an easily identified plant group that can serve as an indicator of general floristic and biogeographical patterns. Tuomisto’s pet group is the ferns, for which she has collected an extensive distributional, ecological, and taxonomical knowledge base. In the DNRF project, she will work closely with researchers focused on other plant groups, especially palms and the family Melastomataceae, to address questions related to the origin of the high species richness in the tropics. For example, how is the process of speciation related to ecological niches, species traits, and the biogeography of species occurrence?