Current projects and interests
My research is centered around understanding how western conifer forests and semi-arid grassland ecosystems "work" from a biogeochemical perspective. I am interested in better understanding how plant community shifts (from human or environmental changes) influence the flow of carbon and nitrogen through the plant-soil-atmosphere continuum. Most recently, my research has concentrated on linking fire-driven plant community shifts to alterations in ecosystem processes important for nutrient cycling and pyrogenic carbon production, as well as understanding how these relationships vary across spatial and temporal scales.
One of the field sites in the Bitterroot National Forest, Ravalli County, MT
Impact of prescribed fire on understory plant community dynamics and pyrogenic carbon production in Northern Rocky Mountain Forests
"As above, so below..."
After a century of exclusion and suppression, fire-prone western US conifer forests have become increasingly reliant on fuel treatments to mitigate wildfire hazard and restore historical ecosystem conditions. The US Forest Service is preparing to significantly expand the area targeted for thinning and prescribed fire to reduce fuel hazard and reestablish historical fire regimes. Despite a wealth of literature and a general consensus on the benefits of fuel treatments for forest structure and fuel reduction, there remains greater uncertainty and geographic variability regarding the response of understory plant communities to fuels treatments.
Forest understory communities are crucial components of conifer forest ecosystems, as they harbor high plant biodiversity, provide wildlife habitat, and play a key role in essential ecosystem services such as nutrient and carbon cycling. Despite the vital roles played by the understory, only a few studies have systematically addressed the long-term effects of fuel treatments on understory vegetation beyond the initial short-term response. Previous studies on understory response to fuels treatments have rarely extended past three years of observation and have primarily focused on plant functional types as opposed to species level response. Importantly, there is a lack of research evaluating the potential ecological tradeoffs associated with fuel treatments on understory plant community dynamics. These tradeoffs include risks of plant invasion, changes in nutrient cycling and availability, and impacts to carbon cycling. Moreover, our understanding of understory response to fuels treatments is likely to be influenced by recent human-driven environmental changes, such as climate change and increased human disturbances. These changes have altered environmental conditions, which may override the current inertia of understory communities and favor the establishment of plant communities with traits better suited to the modified conditions.
Reducing fuel hazard and controlling invasive species are critical needs in many of our nation’s forests and these two issues have been identified by the Forest Service as among the top four threats to our National Forests. Thus, the main objective of this project is to determine how understory vegetation responds to fuel treatments and to better understand how local, landscape, and human factors influence the vegetative response, with a focus on nonnative species dynamics.
Biogeochemical impacts of prescribed fire for managing woody plant encroachment in the central Montana Missouri River breaks
Woody plant expansion (WPE) into grasslands is a well-documented phenomenon, yet the effects on ecosystem biogeochemical cycling remain poorly understood. Recently observed trends in the increase of WPE and ecosystem productivity in the Northern Great Plains (NGP, Currey et al. 2022, Brookshire et al. 2020) have important considerations for 1. determining the trajectory of ecosystem carbon storage, 2. constraints on further WPE, and 3. effects on future nitrogen availability. Yet, many questions remains on how the reintroduction of fire will interact with WPE in these ecosystems.
One hypothesis my work explores is that the expansion of trees into grasslands increases fire severity and thus increases nitrogen loss (volatile and runoff) from the ecosystem. Yet, it is unknown how this increased tree driven N loss affects ecosystem function compared to previous grassland conditions. Thus, the confluence of the recent widespread fire suppression in the NGP and expanding conifer trees into grassland has likely had biogeochemical consequences that have been relatively unexplored at the ecosystem scale.
Taken together, I am interested in understanding how the introduction of prescribed fire to these landscapes has interacted with the recent WPE of conifer species (ponderosa pine and juniper scopulorum) and their synergistic effects on the C and N cycles. Furthermore, I am evaluating how the combustion and mortality of different woody plant species will impact biogeochemical processes and plant community recovery.
The field site is located in the Musselshell-Missouri River Breaks, Petroleum County, MT.
Below ground processes and forest regeneration after short-interval high-intensity wildfire in subalpine Lodgepole pine (Pinus contora) forests
This project is just launching, but through a collaboration between the University of Montana and the USFS Fire Sciences Lab, we are leveraging a reburn chronosequence across the Sapphire Mountains south of Missoula. Our goal is to examine how lodgepole pine forest overstory and understory vegetation communities are being impacted by short-interval, high-intensity reburns.