My research interests span the fields of ecosystem ecology, plant physiology, global change biology, remote sensing, and biogeochemistry in both terrestrial and wetland ecosystems. I am interested in the mechanisms that control ecosystem carbon (C) cycling resistance to and recovery from disturbances and extreme climatic events, as well as how ecosystem structure, resource-use efficiency, and climatic gradients influence these responses. To address these questions, I utilize methods that bridge multiple spatial-scales, from meta-analysis to leaf-level physiology to remote sensing and eddy-covariance flux tower techniques. My ongoing projects range from forest resilience to beech bark disease to the greenhouse gas balance of restored versus established wetlands.
Impact of moderate disturbance on forest productivity
In these projects we are investigating how moderate disturbance severity, resulting in a gradient of heterogeneously distributed mortality, impacts the productivity and canopy structural complexity of temperate deciduous forests. Our study sites include 1) a large-scale experimental manipulation beginning in 2008 which resulted in a 39% loss of tree basal area across 39 ha of mid-successional forest, and 2) an old-growth forest stand in which beech bark disease began afflicting 20% of canopy basal area in 2014.
- Fahey, R.T., Stuart-Haëntjens, E.J., Gough, C.M., De La Cruz, A., Stockton, E., Vogel, C.S., and Curtis, P.S. 2016. Evaluating forest subcanopy response to moderate severity disturbance and contribution to ecosystem-level productivity and resilience, Forest Ecology and Management 376: 135-147. DOI: 10.1016/j.foreco.2016.06.001
- Stuart-Haëntjens, E.J., Fahey, R., Curtis, P.S., Vogel, C.S., and Gough, C.M. 2015. Net primary production of a temperate deciduous forest exhibits a threshold response to increasing disturbance severity, Ecology 96(9): 2478-2487. DOI: 10.1890/14-1810.1
Drivers of productivity in a mid-successional temperate forest
In this project, we aim to identify climatic and biological variables controlling net ecosystem production, or the rate of carbon (C) storage, in a temperate, deciduous forest undergoing a successional transition. North American temperate forests have been a net C sink over the last century, but are rapidly approaching maturity and are more frequently disturbed by pests, pathogens, and extreme weather, making the future of this C sink uncertain. Recent C cycling studies demonstrate that older forests, against theoretical expectations, may continue to accumulate C into middle and late stages of succession; however, the mechanisms underlying sustained rates of C storage in aging US forests are not known. At our site in northern Michigan at University of Michigan Biological Station, I am using continuous multi-decadal data from meteorological “flux” towers to challenge theoretical assumptions about C storage declines in aging forests and investigate the ecological drivers underlying the long-term C cycling trends.
Biogeochemical cycling of restored tidal freshwater wetlands
Land-use change has led to the decline of wetlands throughout North America. In recent decades, however, changes in policy, as well as increased awareness of the important ecological and societal services wetlands provide, have prompted wetland restoration and creation efforts. The goal of many restoration projects is to recreate pre-disturbance ecosystem structure, with the assumption that functional restoration will follow. However, the success of co-occurring functional and structural restoration is variable and rarely quantified, producing uncertainty in the restoration of flood control, wildlife habitat, and carbon (C) cycling and storage. The overarching objective of this research project is to compare soil C stocks and soil CO2 and CH4 fluxes in restored and established temperate tidal freshwater wetlands to determine whether restoration “restores” soil biogeochemical functioning in temperate tidal freshwater wetlands. The restored wetland associated with this project is a registered AmeriFlux site, with freely downloadable data here.
- In the press:
Forest and grassland resistance and resilience to extreme drought
Extreme drought continues to increase in frequency and extent, with uncertain consequences for important ecosystem functions that impact biogeochemical functioning, including primary productivity. Here, we use meta-analysis to evaluate both the resistance (initial response) and the resilience (recovery after one year) of grassland and forest primary production following extreme drought events.
Collaborators: Hans J. De Boeck, Nathan P. Lemoine, Pille Mänd, György Kröel-Dulay, Inger K. Schmidt, Anke Jentsch, Andreas Stampfli, William R.L. Anderegg, Michael Bahn, Juergen Kreyling, Thomas Wohlgemuth, Francisco Lloret, Aimée T. Classen, Christopher Gough, Melinda D. Smith
- Stuart-Haëntjens, E.J., De Boeck, H.J., Lemoine, N.P., Mänd, P., Kröel-Dulay, G., Schmidt, I.K., Jentsch, A., Stampfli, A., Anderegg, W.R.L., Bahn, M., Kreyling, J., Wohlgemuth, T., Lloret, F., Classen, A.T., Gough, C.M., and Smith, M.D. 2018. Mean annual precipitation predicts primary production resistance and resilience to extreme drought, Science of the Total Environment 636: 360-366. DOI: 10.1016/j.scitotenv.2018.04.290