You are here
Harvard Forest REU Symposium Abstract 2023
- Title: Impact of mycorrhizal crowding patterns on soil nutrient acquisition
- Author: Katherine G Almquist (Skidmore College)
- Abstract:
Mycorrhizal fungi are the extension cords of the underground soil ecosystem. As an extension cord lengthens the flow of power, allowing one to be stationary, mycorrhizal fungi act as an elongation of the roots of plants by forming a symbiotic relationship with them. The two primary types of mycorrhizal fungi: arbuscular (AM) and ectomycorrhizae (EM), both have an extracellular hyphal network used for nutrient foraging, but there are still vast differences among them. While AM and EM generally forage for their preferred form of nutrients, competition is still present and a driving factor impacting underground ecosystem dynamics. We hypothesize that trees surrounded by a different mycorrhizal type, hetero-mycorrhizal crowding (AM-EM), will increase competition and competition between trees surrounded by the same mycorrhizal type, con-mycorrhizal crowding (AM-AM) and (EM-EM), will decrease competition. We also expect colonization rates of AM and EM fungi to decrease as competition for primary soil nutrients (nitrogen and phosphorus) decreases. We propose an observational field experiment to explore these hypotheses, collecting data on 40 trees from 20-20-meter plots chosen from the 35-hectare ForestGeo plot at Harvard Forest in Petersham, MA. Each tree was selected for root and soil collection based on tree type, Acer rubra or Quercus rubra, and type of mycorrhizal colonization, arbuscular (AM) or ectomycorrhizae (EM). Mycorrhizal presence is expected to impact soil pH, carbon-to-nitrogen ratio, and provide insight into the impact of mycorrhizal interactions on soil nutrient acquisition strategies. Studying the crowding index and belowground nutrient acquisition strategies is fundamental in explaining the importance of mycorrhizal fungi and their impact on changing global ecosystems.
- Research Category: Soil Carbon and Nitrogen Dynamics; Physiological Ecology, Population Dynamics, and Species Interactions
