Soil fungi provide many vital woodland ecosystem functions including nutrient cycling and plant-fungi mutualisms. Disturbance-driven changes to soil fungal communities can impact these processes and change local ecosystem stability. Ecological network theory explores these complex dynamics by investigating how network structure might vary with disturbance. One large disturbance to woodland ecosystems is urbanization, which includes land use and biophysicochemical changes. These factors can alter the soil environment and their beneficial fungal communities. In this study, we assessed how the soil-fungal community association network might vary across an 80 km urbanization gradient starting in New York City. We predicted that the abiotic and biotic factors altered by urbanization will correlate with soil-fungal community structure.
We collected soil cores from nine woodland locations from New York City to Fahnestock State Park. At each location we set up three 3 x 3 m sampling plots along a 30 m transect with each plot separated by 15 m. We also completed a vegetation analysis of the surrounding tree species within the plot. From 94 soil cores, we performed elemental analysis and amplified fungal DNA using the ITS1F-ITS2 primers. Sequences were analyzed in QIIME2, UNITE, and Cytoscape to assess fungal diversity and association network structure.
Results/Conclusions
Our results suggest that soil fungal community composition and network structure varied distinctly among the nine urban-to-rural locations. The change in fungal community composition was most closely associated with distance away from our urban center. Additionally, each location had a majority of OTUs that were distinct to that location. This may be the result of effects of urbanization on soil, as suggested by our elemental analysis, which shows significant differences in K, P, Zn, Mn, Fe, and Pb along the gradient (p < 0.05). These results are consistent with those from similar studies. Future research will further explore disturbance effects to microbial communities of northeastern forests.