COS 180-6 - A tale of two mutualists: how does arbuscular mycorrhizal fungi impact pollination and plant fitness in an anthropogenically disturbed environment?

Background/Question/Methods

Mutualistic interactions with other organisms drive species’ ecological and evolutionary trajectories and can be crucial for plant survival in stressful environments. Plants engage with a variety of above- and belowground partners, including pollinators and arbuscular mycorrhizal (AM) fungi. These mutualisms can also influence each other. For example, AM fungi can alter floral traits that function in pollinator attraction, but few studies have linked the impact of AM fungi to pollinator visitation and plant fitness. In addition, little is known about how plant-AM fungal and plant-pollinator mutualisms interact in environments with a history of anthropogenic disturbance. The Wilds is a conservation park in eastern Ohio located on formerly surface-mined land. Sites across The Wilds experienced different reclamation histories, from no improvement to full grassland prairie establishment. In a greenhouse study, we inoculated five perennial plant species common at The Wilds that provide resources for pollinators (Solidago canadensis, Echinacea purpurea, Clinopodium vulgare, Monarda fistulosa, and Mentha spicata) with AM fungal spores collected from sites with different reclamation histories. We aim to determine whether the AM fungi from these sites differentially affect plant growth, flower number, flower size, nectar and pollen quantity and quality, pollinator visitation, and seed set.

Results/Conclusions

We found that sites at The Wilds with a more comprehensive reclamation history have a greater number of AM fungal spores than sites with no reclamation history, but there is no difference in morphotype richness or Shannon diversity between sites. Preliminary results indicate that AM fungi improve plant survival, and that plants inoculated with AM fungi from sites with no reclamation history are taller, perhaps because the more stressful environment in such sites strengthens the plant-AM fungal mutualism. By contrast, plants inoculated with AM fungi from sites with a more comprehensive reclamation history produce more flowers with a greater area of attractive floral tissue. Our results have implications for pollinator visitation and plant fitness. Plants with more flowers have relatively more chances to interact with pollinators and larger flowers may be more attractive to pollinators, both of which could potentially increase reproductive success. This suggests that increased restoration effort and the plant-AM fungal mutualism may help plant communities to recover from anthropogenic disturbance and persist long-term, lending hope to the conservation potential of similar environments.