About

PFR_BlueLakesH_02

Paleoecology, retrospective studies, long-term environmental change, are synonyms that allude to the rich history of ecological processes that take longer than one researchers career to play out. The history of locations can be told through plant community responses to environmental change that occurred after the last glacial period to now is important to know simply because modern ecological patterns are largely based on how ecosystems responded to past variations in climate, disturbance and community composition.

 

PROJECTS

History of Ciénegas in the Desert Southwest.

Ciénegas are were widespread wetland environments distributed across North American Deserts prior to widespread settlement in the late 1800’s. We have been examining the development, growth, and environmental history contained in these deposits to better understand how desert ecosystems evolved from the woodlands of the last glacial period to present.

Unlike lakes, which record vegetation change in a relatively predictable way, ciénegas are often located within fluvial environments. This means the taphonomy of the sediments and of pollen and macrofossil deposition within that sediment must be understood to interpret these records.

We have been looking how vegetation and sediment deposition have interacted to “grow” these deposits. We are also looking at pollen and isotopic signatures to determine local and regional vegetation history. Finally we are interested in the disturbance history, both floods and fire, and how those data might inform changes water availability in the past.

Collaborators:

Dr. Andrea Brunelle (University of Utah)

Dr. Mark Clementz (University of Wyoming)

Dr. Jose Delgadillo (Universidad Autonoma de Baja California)

Dr. Sally Horn (University of Tennessee)

Vegetation response to long and short term drivers, like drought and fire

Knowing the resilience of forests to long and short and term disturbances in the past is important for identifiying those ecosystems most vulnerable to changes in climate and fire-regime shifts. Also society depends on ecosystems for clean air, water supplies, and recreation. As the West continues to develop, there is a pressing need to understand the vulnerability of ecosystems to the pressures placed on them from multiple forces.

Water supplies are crucial to the continued development of the western United States. We are conducting an integrative study that examines modern climate variability that promotes drought in the central Rocky Mountains, spatial patterns of low-lake levels, indicating periods of prolonged drought beyond the historical record, and the environmental consequences of those drought events. Potential environmental consequences to these events include changes in forest composition and changes in fire regimes. We are asking what is the resilience of present-day forests to past “mega-droughts” that persisted from centuries to millennia.

We are also looking at how fire may shape forest composition and response under different climate regimes (e.g., periods of drought) and how external forcing may results in different responses on timescales of decades to millennia.

We have been examining the paleoenvironmental history of a transect of lake sites in southeast Wyoming from below the forest boundary to above upper tree-line. Proxy data include buried shorelines, sediment density and composition, pollen, macro-botanical remains, and charcoal. Our goal is to determine potential decreases of regional water levels during extremely dry periods and what the broad scale impacts those periods have on plant communities.

Collaborators:

Dr. Simon Brewer (University of Utah)

Dr. Andrea Brunelle (University of Utah)

Dr. JJ Shinker (University of Wyoming)

Dr. Bryan Shuman (University of Wyoming)