Linking pattern and process in community assembly

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Ecological processes including competition, predation, and dispersal play important roles in structuring natural communities. However, it remains unclear how these processes contribute to several compelling and insufficiently explained patterns of species organization, abundance, and diversity. The central goal of my research program is to address gaps in our understanding of how ecological processes contribute to these intriguing patterns. By extending our knowledge of how communities are assembled, my research can inform conservation and restoration initiatives and help mitigate the negative impacts of invasive species and climate change. I conduct this research primarily in terrestrial plant communities. Experiments indicate that large plant species are better competitors for light; however, small species remain common in vegetation where competition is intense. My goal is to understand how small species to persist in competitive communities by 1) determining whether smaller plant species survive competition with taller species by growing and flowering earlier in the season, when light resources are less contested, 2) testing for evidence that small, non-ephemeral plant species in herbaceous communities exhibit shade tolerance, and 3) examining whether a size-advantage is more apparent when competition is more intense, or in response to rapid plant growth following soil fertilization. To understand the processes that organize species within communities, I examine why some species are regularly found together or apart (positive and negative co-occurrence, respectively), and why coexisting plant species differ in some fundamental characteristics (e.g. flowering time). My research will increase our understanding of co-occurrence patterns by 1) using data from a global network of experiments to test whether negatively co-occurring pairs of species are more likely to decrease in abundance over time in response to fertilization, and 2) testing whether species co-occurrence patterns are related to variation in soil nutrients and competition intensity (estimated in the field). My research will also investigate why coexisting plant species overlap in flowering time less than expected by testing: 1) whether seed production improves when neighbouring plant species do not overlap in flowering time, and 2) whether overlap in flowering time among coexisting species is influenced by the intensity of competition experienced. My proposed research program will answer fundamental questions concerning how small plant species avoid being outcompeted by larger species, what processes drive patterns of species co-occurrence, and what factors contribute to observed flowering time asynchrony among coexisting plant species. This research addresses specific and fundamental questions about how ecological processes contribute to incompletely understood patterns of species organization in plant communities, addressing key questions in the field of plant ecology.