Research
TRACE lab is broadly interested in how terrestrial climate and environment has changed through time. We study these changes on many different timescales, from decades in recent time to millions of years in geologic time.
Mice-o-scapes: Using Small Mammals to Understand Past Climatic and Landscape Change
Small mammals are very common in the fossil record, but before we can use them as paleoclimatic and environmental indicators of past change, we must first understand how change is recorded in their body tissues in the present. We are currently funded by NSF Macrosystems Biology to study what small mammals can tell us about recent landscape and land use change at the regional and continental scale. We are currently focusing Peromyscus maniculatus (deer mouse) hair as a proxy for climate and landscape change on the West Coast of the United States over the past 100 years. We are using samples from natural history museum specimens and the National Ecological Observatory Network (NEON) to determine how signals of urbanization, hydrologic change and deforestation may be recorded in the isotopic composition of small mammals through time.
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Past, Present and Future Biogeography of C4 Grasses
The evolution and expansion of C4 grasses is one of the most dramatic ecological changes in the Cenozoic, but the causes for this expansion are still not well understood. Economically important C4 grasses such as corn, sugarcane and sorghum are more efficient than C3 grasses in high temperature conditions and also under low atmospheric CO2. Given that both temperature and CO2 will increase in the future, the response of grasslands to future climate change not well constrained. TRACE lab involved in a number of projects to try to address the evolutionary history of C4 grasses and how they may respond to future climate change, most notably an NSF Sedimentary Geology and Paleobiology funded project to determine the link between the spread of C4 grasses and tectonic and climate changes in South America. The photo above is from one of our field sites in northwest Argentina. For this work we use isotopic data from soils, plants and animals as well as modeling techniques to determine climate controls on the distribution of grasses and predict past and future grassland biogeography.
Paleoenvironment, Paleoclimate Reconstructions and Earth System Feedbacks
TRACE lab is interested in reconstructing past terrestrial climatic and environmental change using soils, plants and animals to better understand the sensitivity of ecosystems to climate change. We work on numerous timescales, but are most interested in time period analogous to future climate change conditions such as the Paleocene/Eocene Thermal Maximum and the Miocene Climatic Optimum. We are also exploring the signature of climate feedbacks in the geologic past, including positive feedbacks from soils that may contribute additional carbon to the atmosphere during warming events, and fire feedbacks that may have contributed to the expansion of C4 grasses in the Miocene. Pictured above: Miocene aged paleosol site in southwestern Montana.
Atmospheric CO2 Reconstructions through Geologic Time
To predict better future climatic and environmental changes, we must first understand how sensitive Earth’s climate is to changes in atmospheric composition as well as how sensitive ecosystems are to climatic changes in the geologic past. The sensitivity of Earth’s climate to changes in atmospheric CO2 throughout geologic time is not well understood. TRACE lab is interested in reconstructing more precisely the atmospheric CO2 levels and temperature during times in the geologic past analogous to future climate change in order to provide better constraints on the magnitude of future climate and on predictions of likely environmental changes. Pictured above: Miocene aged La Vina field site in Northwest Argentina with paleosol containing pedogenic carbonates that can be used to reconstruct atmospheric CO2.