Quantifying the effects of plant-soil feedbacks on light-gradient partitioning as a mechanism for maintaining tree species diversity
Project 1 PI's: Dr. Richard Kobe (MSU), Dr. Sarah McCarthy-Neumann (MSU, Alma College), Dr. Inés Ibáñez (U. Mich.) Funding: Plant-soil feedback and species coexistence: interactions among soil pathogens, irradiance, and species life histories (2015-2018), NSF-DEB, PI: Sarah McCarthy-Neumann, CoPI’s: Richard Kobe and Inés Ibáñez
We are using a novel field-based transplant experiment at Alma College's Ecological Field Station in Michigan, using fungal exclusion pots to mechanistically investigate both tree seedling response to plant-soil feedbacks as a function of light availability and response to low light as a function of plant-soil feedback. This approach will allow us to investigate the degree to which plant-soil feedbacks maintain species coexistence through, not only negative density-dependence, but also as an underlying component creating light-gradient partitioning among tree species. I am the lead graduate student on this project and will be working with undergraduate students at Alma College to collect and analyze data.
Project 2 Co-PI's: Dr. Richard Kobe (MSU), Dr. Sarah McCarthy-Neumann (MSU, Alma College)
I am using a greenhouse experiment at Michigan State University to quantify the effects of fungi on tree seedling light-gradient partitioning in order to understand how these interactions may maintain tree species diversity. I am manipulating light level in addition to pathogen and mycorrhizae presence, while measuring carbohydrates that confer defense and recovery from attack.
Phylogenetic and functional relatedness as drivers of neotropical tree seedling negative density dependence
Co-PI: Dr. Richard Kobe (MSU)
I am currently analyzing the long term ecological research dataset generated by the Kobe research group, documenting seedling dynamics in five plots at La Selva Biological Station, Costa Rica over thirteen years. Using phylogenetic analyses and functional trait measurements, I hope to decipher the relationship between phylogenetic and functional relatedness as a driver of neotropical tree seedling negative density dependence in this forest. This study is unique, as it utilizes a long term dataset with precise ages and identifications of the seedlings, in conjunction with functional trait measurements and environmental data. For this project, I am using Corine Vriesendorp's (The Field Museum of Natural History, Chicago) guide to seedlings/virtual herbarium.
Undergraduate senior thesis: testing the Janzen-Connell hypothesis
Co-PI: Dr. Marcel Rejmanek (UC Davis) Funding: UC Davis Provost Undergraduate Fellowship
My undergraduate senior honors thesis investigated the Janzen-Connell hypothesis, which predicts that tropical tree diversity is maintained through a combination of density- and distance-dependent seedling recruitment and host-specific predation. Herbivory and pathogenic damage reduce conspecific seedling density, thus keeping intra-specific density low and increasing within-habitat species diversity. I conducted an observational field study at Barro Colorado Island in Panama (hosted by Dr. Joseph Wright) and measured conspecific seedling fitness and damage from herbivores and pathogens for Protium tenuifolium seedlings in order to determine whether these seedling populations are in concordance with the Janzen-Connell hypothesis. I presented the results at the 2014 UC Davis Undergraduate Research Conference.