Mutualisms can drive population dynamics and evolutionary processes, but there is still only a limited understanding of how mutualisms may be important to communities. Resource mutualisms, such as the interaction between legumes and nitrogen-fixing rhizobia, not only directly influence the partners involved in the interaction, but they also have the potential to either inhibit or facilitate other species in the community by altering the abiotic and biotic environment. Yet, understanding the role of mutualisms in a community context has typically received less attention than other species interactions. Moreover, there is substantial intraspecific genetic variation in legumes and rhizobia, including variation in legume growth, rhizobia population size, and nitrogen fixation. Therefore, not only can the presence of particular species influence the community, but the colonizing genotype could also alter these processes when they vary in traits associated to ecologically important interactions with rhizobia. My research has taken an empirical approach that combines large-scale field and greenhouse studies with smaller targeted studies to explore the role of plant-microbe mutualistic interactions on community interactions and host responses to availability and changes in these mutualisms. My findings expand our understanding of plant community dynamics by incorporating the effects of positive symbiotic interactions through nitrogen-fixing bacteria on plant communities and how they are dependent on intraspecific variation in traits related to species interactions, abiotic and biotic environmental conditions, and even the presence of other mutualists.
Read
