Soil fungi, integral to maintaining ecosystem health, face increasing threats from rapid changes to climate and land use. Soil fungi play pivotal roles not only in nutrient cycling and organic matter decomposition but also in forming symbiotic relationships that are essential for plant growth and survival. However, understanding how these critical organisms respond to global change is limited by the scope of current data and the complexity of ecosystem interactions. Our project sought to bridge this knowledge gap by synthesizing previous large-scale molecular sampling efforts for soil fungi in North America and developing novel modeling approaches for investigating the identity and magnitude of key global change factors influencing fungal biodiversity. Using this approach, we made a number of important discoveries that change our understanding of the relationship between fungi, trees, and climate, and will form the basis for future ecological studies and forest conservation efforts.

First, while soil fungi have generally been thought to be influenced primarily by soil chemistry, our findings showed that temperature, especially its fluctuation over the seasons, is a principal driver of where fungi are found across various North American landscapes. In particular, we observed that North American soil fungi are more constrained by colder, drier climates than by warmer, wetter ones. This suggests that as the climate warms, we might expect significant changes in fungal communities, with notable species losses and gains in different regions. For instance, areas such as the northwestern conifer forests are projected to experience substantial species loss due to warming, while eastern temperate forests may see an increase in diversity for ectomycorrhizal fungi. This indicates a complex reshuffling of fungal species compositions under climate change rather than uniform patterns of diversity loss or gain, with unknown implications for ecosystem functions.

Second, in addition to assessing direct climate impacts, we delved into how climate indirectly affects fungal biodiversity by influencing the co-distribution of host plants with which fungi form symbiotic relationships. By building separate models predicting the potential future geographic ranges of trees and the fungi with which they form mycorrhizal partnerships, we found that climate change could reduce overlapping habitats for ⅓ of mycorrhizal fungal species. We also used seedling recruitment data and found empirical support that the predicted reduction in shared habitat could slow tree migration in response to climate change, as essential fungal partners are unavailable to support new seedling growth. Furthermore, through the development of new diversity scaling models, we predicted that climate-change-induced land-use changes might lead to widespread local declines in fungal species diversity, especially in temperate forests and grasslands. However, in certain conifer biomes, the conversion of natural landscapes to human-dominated systems could potentially boost diversity in arbuscular mycorrhizal fungi and certain plant pathogens, highlighting an intricate interplay between climatic shifts, land-use changes, and fungal communities.

On top of addressing these significant scientific inquiries, our project has contributed valuable resources to the research community, including standardized DNA-based fungal community datasets and detailed range maps. These tools have already begun to facilitate the incorporation of microbial perspectives into broader ecological and environmental research initiatives.

Additionally, this project provided a platform for the educational and professional development of next-generation scientists. By engaging undergraduate and graduate students, as well as postdoctoral researchers from the University of Michigan and Stanford University, we offered comprehensive training in microbial genomics, advanced experimental design, and effective scientific communication. This hands-on experience has empowered participants to pursue advanced academic qualifications, take on faculty roles, and enter industry positions, thereby expanding the reach and impact of our findings.

As an early-career research grant, this undertaking also played a vital role in the professional advancement of our team, aiding in securing tenure and establishing foundations for continued research endeavors. Beyond the scientific and professional achievements, our work underscores the broader relevance of understanding ecological dynamics in the face of climate change. By enhancing public awareness of these critical environmental issues, we contribute to better-informed management of natural resources, ultimately fostering more resilient ecosystems.

In summary, this project has successfully advanced knowledge at the intersection of ecology, microbiology, and climate science, providing fresh insights into how fungal diversity is influenced by and, in turn, affects environmental change. The broader impacts of this research extend to policy-making, resource management, and public education, emphasizing the vital role of microorganisms in global change biology.

Last Modified: 03/11/2025
Modified by: Kabir G Peay