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Regional Climate Change and Carbon Cycling on the Colorado Plateaus: Tamara Jane Zelikova

Project Title: Regional Climate Change and Carbon Cycling on the Colorado Plateaus
Mendenhall Fellow: Tamara Jane Zelikova, (435) 719-2335,
Duty Station: Moab, UT
Start Date: October 1, 2010
Education: Ph.D. (Ecology and Evolutionary Biology), University of Colorado, 2008
Research Advisors: Sasha Reed, (435) 719-2334,; Jayne Belnap, (435) 719-2333,; Nichole Barger (University of Colorado), (303) 492-8239; Rich Reynolds, (303) 236-1303,; Michael Dettinger, (858) 822-1507,; Carol Kendall, (650) 329-4576,;  Jennifer Harden, (650) 329-4949, jharden@usgs,gov
  Tamara Jane Zelikova

Project Description:

Soils store more carbon than plants, animals, and the atmosphere combined; thus, subtle changes to soil carbon cycling, such as those associated with land use and climate change, could have dramatic effects on atmospheric CO2 concentrations. Historically, soils in arid ecosystems were considered to store and cycle relatively little carbon. However, recent work suggests that C uptake rates in desert ecosystems are substantially larger than previously thought and may be comparable to rates observed in temperate forests and grassland ecosystems. These data, in conjunction with the fact that dryland ecosystems comprise 40 percent of terrestrial land mass and 35 percent of the United States suggest that changes to dryland C cycling will have large ecological and political implications. Because CO2 efflux from soil can be highly sensitive to changes in temperature and soil moisture, changes in climate may strongly affect C loss to the atmosphere from these extensive dryland soils.

Photograph of the Colorado Plateaus   Coupled with the effects of a changing climate are the concurrent and rapid changes in land use across dryland ecosystems. Arid lands in the western United States are identified as the fastest growing and fastest warming in the nation. The Colorado Plateau in particular is changing at an especially rapid rate and holds vast expanses of public lands, yet we know remarkably little about how these ecosystems will respond to predicted changes in climate.

Using a combination of field experiments, laboratory incubations, and existing data, this project will provide model parameters to help predict how regional biogeochemical and ecosystem processes on the Colorado Plateau will respond to a changing climate, to land use, and to the interacting effects of these two factors.  A soil core transplant experiment will be used to examine the response of soil respiration to changing temperature and precipitation across a natural climate gradient from Moab to the LaSal Mountains. Moving soils across the full range of climatic conditions will allow us to determine what happens when soils that are adapted to a set of conditions experience conditions outside their range of adaptation, allowing us to simultaneously measure the response of soil respiration to changing temperature and moisture conditions. Making use of grazer exclusion treatments established across the elevational gradient >15 years ago, we will examine how grazing interacts with climate factors to affect soil respiration. The experiments outlined above will also be supported with laboratory incubations to address the mechanisms of soil response. In particular, laboratory incubations provide the platform to directly explore the threshold responses of soil moisture to changes in temperature and soil moisture. Taken together, these data will be instrumental in helping the U.S. Geological Survey, land management agencies, and citizens to prepare for local and regional changes and enhance the efficacy of decisionmaking.

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Last modified: 16:08:34 Thu 13 Dec 2012