Research Framework
I am a community ecologist who uses field observations and theoretical models to describe community processes. Within this framework, I am driven by these guiding questions:
1. How do interacting anthropogenic stressors affect species relationships?
2. How do these shifting relationships scale to affect ecosystem function?
1. How do interacting anthropogenic stressors affect species relationships?
2. How do these shifting relationships scale to affect ecosystem function?
Mutualisms in the Tehachapi Mountains
To answer these questions, I designed an experiment studying the mutualism between root ectomycorrhizal fungi (EcM) and oak host (Quercus spp.) relationships at the Tejon Ranch Ecological Experiment (TREE) located within the Tejon Ranch Conservancy in California at sites shared with my fellow labmate Devyn Orr. TREE is a large-scale ungulate exclosure experiment, where native ungulates (e.g. deer and elk) and introduced ungulates (e.g. cows) are experimentally excluded from plots at three different aridity levels defined by fine-scale climate data for each site (Figure 1). I am leveraging this unique experimental design to elucidate the interactive effects of land use change and climate context on EcM communities.
EcM are directly responsible for ecosystem nutrient exchange, associating with tree hosts in a mutual relationship in which EcM exchange soil nutrients like nitrogen and phosphorus with trees for carbon. This mutualism is foundational to ecosystem function, responsible for 50% of the soil respiration (Hogsberg & Hogsberg 2002) and 50-70% of stored soil carbon in forest habitats (Clemmenson et al. 2013). In California, EcM communities in oak woodlands are particularly imperiled by anthropogenic change, from rangeland expansion (Asner et al. 2004) to changing climate regimes (Williams et al. 2015).
In this project, I ask how aridity and ungulate density affect functional communities of EcM. I hypothesize that more stress-tolerant species (e.g. hydrophobic, rhizomorph-forming, and long-distance foraging) will be present in heavily grazed plots, and that these species will dominate EcM communities at arid sites. To test this hypothesis, I have collected fungal root tips and fungal community samples to collect genetic data to identify species and assign function using fungal databases.
EcM are directly responsible for ecosystem nutrient exchange, associating with tree hosts in a mutual relationship in which EcM exchange soil nutrients like nitrogen and phosphorus with trees for carbon. This mutualism is foundational to ecosystem function, responsible for 50% of the soil respiration (Hogsberg & Hogsberg 2002) and 50-70% of stored soil carbon in forest habitats (Clemmenson et al. 2013). In California, EcM communities in oak woodlands are particularly imperiled by anthropogenic change, from rangeland expansion (Asner et al. 2004) to changing climate regimes (Williams et al. 2015).
In this project, I ask how aridity and ungulate density affect functional communities of EcM. I hypothesize that more stress-tolerant species (e.g. hydrophobic, rhizomorph-forming, and long-distance foraging) will be present in heavily grazed plots, and that these species will dominate EcM communities at arid sites. To test this hypothesis, I have collected fungal root tips and fungal community samples to collect genetic data to identify species and assign function using fungal databases.