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Harvard Forest Research Project 2024
- Title: Testing the Role that Biotic Interactions Play in the Latitudinal Diversity Gradient: A Chemical Community Ecology Approach to Understanding Tree Diversity
- Principal investigator: Jonathan Myers (jamyers@wustl.edu)
- Institution: Washington University in St Louis
- Primary contact: Jonathan Myers (jamyers@wustl.edu)
- Team members: Gibson Blankenship
Anna Wassel - Abstract:
Foundational hypotheses in ecology and evolution posit that variation in the strength and specialization of interactions among plants and their natural enemies contributes to latitudinal gradients in biodiversity. Plant-enemy interactions are mediated by plant-secondary metabolites, organic molecules that function as chemical defenses against herbivores and pathogens. If herbivores and pathogens are a stronger determinant of plant community diversity and dynamics in the tropics, they should select for greater divergence in secondary metabolites among co-occurring plant species and promote higher diversity of plant species through chemically-mediated niche differences among plants. To test these hypotheses, we will couple recent innovations in ecological metabolomics with existing data on the diversity and dynamics of forest-tree communities that span large-scale gradients in climate, latitude, and tree-species diversity from boreal forest in Canada (11 species in 21 hectares [ha]) to tropical rainforest in Amazonia (>1,200 species in 25 ha). Our project will leverage existing data on the growth, survival, and mapped distributions of more than 3,600 tree species in 20 large-scale forest-dynamics plots coordinated by the Smithsonian Forest Global Earth Observatory (ForestGEO) and San Diego Zoo Global, as well as existing metabolomics data from 13 forest plots. Building on these data, we will collect and analyze leaves of 1,367 species in 7 new forest plots—including the Harvard Forest ForestGEO plot—that represent unique climates and/or provide key seedling performance datasets. We will combine metabolomics data, neighborhood demographic models, and theoretical simulations to determine i) how leaf-secondary chemistry shapes local species interactions within tree communities, ii) how the effects of leaf-secondary chemistry on local species interactions vary across latitudinal and climatic gradients, and iii) the importance of chemically-mediated niche differences in maintaining species diversity across latitudinal and climatic gradients.
