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Climate change and cheatgrass (Bromus tectorum) invasion

Several recent studies suggested that global change might expand Cheatgrass’ range into higher elevations of the Rocky Mountain range. To directly test this hypothesis, I have set up an experiment testing the effect of temperature warming, competition and cheatgrass seed provenance on cheatgrass’ population growth rates. Warming is simulated with open top chambers over an elevation gradient along sagebrush communities of the Wasatch foothills. The growth of different cheatgrass seed provenances is compared among plots that are warmed, cleared of neighboring vegetation and untouched. This study addresses the following questions:

  • Is cheatgrass mostly limited by temperature at high elevations?
  • What is the contribution of competition from the surrounding vegetation in decreasing cheatgrass success?
  • Does seed provenance influence cheatgrass growth rates?

Coexistence of rare plant species

Provided that environmental conservation policies spend considerable effort towards the preservation of rare species, one might expect ecological research to widely address the causes and consequences of rareness. However, this is still a relatively undeveloped field of research, probably because of the technical difficulties involved in addressing it. I plan to address this topic using a model parameterized with long term data collected in the Idaho sagebrush steppe. My advisor, Peter Adler, has successfully used the same approach to answer questions regarding the coexistence of this ecosystem’s dominant plants. I will use the model to address the following questions:

  • What are the mechanisms allowing rare species to coexist in plant communities?
  • Are certain rare species more prone to extinction than others?