The earth is rapidly losing its biodiversity. The consequences of this biodiversity loss for ecosystem functions that humanity relies on, such as water filtration, carbon storage, and pollination, are not well understood. In experiments done with simplified ecological communities, ecosystem functions can be maintained by a small number of species. However, biodiversity may be more important in nature, where ecological communities are more complex. One aspect of this complexity is that in nature, most species rely on beneficial interactions with other species, or mutualisms. For example, flowering plants need animals such as bees to pollinate them, and pollinators require flowering plants as a source of food (nectar and pollen). Yet to date, these networks of mutualist interactions have largely been left out of research on the importance of biodiversity for ecosystem functioning. Thus, the current predictions for how ecosystem functions will change with biodiversity loss might be overly simplistic. In addition to addressing an issue of critical conservation concern, the proposed work will contribute to training the STEM workforce.
This research project will bring mutualism into the study of biodiversity and ecosystem function, using native bee species and the pollination they provide to wild plants as a model system. The PI will use data already collected by members of her research group in the Mid-Atlantic USA. In total, the data include 116,000 individual pollinators of 500 species, and 339 plant species. Within each of 49 plant-pollinator networks, the PI will first determine which bee species are the most important pollinators of each plant species. She will then assess how the number of bee species that are needed for the pollination of at least one plant species increases with the number of plant species considered. Thus, the project will reveal how the importance of biodiversity to ecosystem function increases when entire mutualist networks, as opposed to only one or a few target species, are included. Null models that assume random interactions among bee and plant species will be used to separate the components of this increase that are due to stochastic effects from those that are due to biology. Generalities will be sought by comparing results across the 49 networks. An explicit goal of the project is to explore the role of rare species in ecosystem function. Previous studies focused on the function delivered to one or a few species often find that rare species are not important. However, a bee species that is rare in the overall community might still be an important pollinator of a particular plant, making rare species important to the functioning of the network as a whole. The results of this work will broaden our understanding of biodiversity and its importance to ecosystem functioning in the complex natural world.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
