As individuals grow and develop, they often experience substantial changes in their morphology and behavior. These changes, in turn, frequently alter the interactions of individuals with other members of the community. As a consequence, developmental stages within species can differ substantially in their ecological role and these differences can even exceed differences among species. Although recent research demonstrates that such ontogenetic shifts in the ecology are ubiquitous in natural communities in both plants and animal taxa, they are often ignored in general theory relating biodiversity to the functioning of ecosystems. Yet, our ability to predict how natural and anthropogenic disturbances alter natural ecosystems depends critically on a understanding of the mechanisms that link ecological variation within species to the structure and dynamics of communities and ecosystem processes. This project will address that gap by developing a general framework to predict developmental changes in the ecology of individuals across species and communities, and when and how these developmental changes influence the response of natural ecosystems to environmental disturbances such as selective harvesting. Field experiments will independently manipulate developmental stage and species diversity in a complex community of predatory invertebrates in pond ecosystems. This will provide novel insights into how ontogenetic functional diversity influences the consequences of species loss for community structure and ecosystem processes such as primary productivity. The long-term consequences of ontogenetic shifts for the dynamics and stability of communities will be tested by integrating theory with a set of experiments that manipulate the degree of ontogenetic shift in a plankton community along environmental gradients. Together, these studies will permit a new detailed understanding of how developmental changes within species scale up to affect entire communities and their functioning, and will advance our conceptual understanding of whether and what details need to be included in a general predictive framework for ecosystem functioning.
The results of this project will also have important practical applications. Given that human impacts on natural populations are typically highly selective and affect specific developmental stages within species (e.g. size selective harvesting in fisheries) results from this project can be used to guide the development of conservation and harvest strategies to assure that vital ecosystem functions are not lost in the future. This project will also provide training opportunities for undergraduate and graduate students, including members of groups underrepresented in the sciences, and will support the advanced training and mentoring of a postdoctoral scholar.
