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University of Michigan Biological Station

The University of Michigan Biological Station (UMBS) was founded in 1909.

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Characterizing mycorrhizal communities along a latitudinal gradient for 10 dominant temperate tree species in the eastern United States

Climate
Terrestrial
Vegetation
Project Abstract: 
Mycorrhizal fungi colonize the roots of trees and the vast majority of other plant species, providing the plant with nutrients and water from the soil in exchange for carbon-rich exudates. Mycorrhizal fungi are necessary for trees’ germination, growth, and reproduction; however, it is largely unknown how hosts’ partnership with different species of mycorrhizal fungi varies across their range and how different mycorrhizal partnerships affect tree fitness. An understanding of host-mycorrhizal range dynamics will become important as climate change induces plants to shift their ranges poleward into habitats with mycorrhizal communities that may differ from those of their historic ranges. Establishment of foundational tree species will depend on whether suitable mutualists exist in their new habitats. Numerous tree species native to the eastern United States have overlapping ranges that stretch from Alabama and Georgia to Michigan and have already begun to migrate north, making this an excellent system to study mycorrhizal associations of multiple species along a latitudinal gradient. Sampling from multiple species allows for replication and assessment of differences in mycorrhizal range dynamics of arbuscular mycorrhizal (AM)- and ectomycorrhizal (EM)-associating hosts, whose different nutrient cycling patterns will contribute to understanding of how our future forests will store carbon and nutrients. Here, I will examine how mycorrhizal community composition differs along a latitudinal gradient of five AM-associating and five EM-associating tree species’ ranges and the extent to which suitable partner mycorrhizal fungi are found north of these ranges. Samples will be taken from seven sites that stretch from the southernmost extent of temperate forest in Alabama to north of temperate forest in peninsular Michigan.
Investigators: 
Ella Segal
Status of Research Project: 
Active
Years Active: 
2023
Methods: 
Target AM-associating species are Acer rubrum, Cornus florida, Liquidambar styraciflua, Liriodendron tulipifera, and Sassafras albidum, while target EM-associating species include Fagus grandifolia, Juniperus virginiana, Pinus strobus, Quercus alba, and Tsuga canadensis. UMBS is too far north for many of these species but includes the northernmost populations for others, and I am interested in capturing mycorrhizal fungal compositions at the very northern ends of their ranges. At each site from Alabama to lower peninsular Michigan, I will collect root samples from four to five individuals of five AM- and five EM-associating tree species. Soil cores will be taken with a soil corer under the canopy of each individual tree north, east, south, and west of the tree trunk and pooled to form one sample. I will target trees of similar size and record the diameter at breast height of each plant. Ten to twenty soil cores will also be collected away from target species and pooled to capture fungal communities in soil not conditioned by target species. In sites in peninsular Michigan, where we do not expect to find target tree species, I will only collect ten to twenty soil samples from forest floor not directly under any one tree’s canopy. All samples will be stored in Ziploc bags on ice in the field and transported back to the University of Tennessee, Knoxville for further analysis. DNA will be extracted from .25g of soil per sample with the DNeasy PowerSoil extraction kit. DNA will be quantified with a microplate reader, amplified with ITS2 primers, and meta-barcoded with a MiSeq Illumina sequencer. Sequences will be processed with the DADA2 pipeline into amplicon sequence variants using standard methods in the Kivlin lab (See Kivlin et al. 2021). I will also measure soil biogeochemical properties (e.g., pH, soil nutrients, soil carbon) and climatic variables for each site will be estimated using the CHELSA database. The influence of these variables along with latitude and tree species on mycorrhizal fungal composition and diversity will be parsed using the VarPart function in Vegan in R. I will also assess the turnover in mycorrhizal fungal communities across latitude and the range determinants of specific mycorrhizal fungal taxa to understand if mycorrhizal fungi and plants are shifting their ranges at similar rates with global change.