Breahna Gillespie

Breahna Gillespie
PhD, Graduate

Cohort Level: Cohort - I

Career Goal: I would like to work in some organization in which I am able to interact with the public and further the understanding and appreciation between the community and nature.

Expected Graduation Date: December 21, 2021

Degree: PhD

Research Title: Comparing a +160-year-old chaparral stand gross primary productivity (GPP) to the net ecosystem exchange (NEE) of an eddy covariance tower across seasons

Research Synopsis: Atmospheric carbon emissions have continued to increase, while plants have subsequently removed roughly one-fifth of carbon dioxide. Terrestrial carbon uptake has slowed the rate of CO2 accumulation yet changes in mean temperature and precipitation may negatively impact ecosystems that were previously strong sinks. California chaparral stands in particular potentially could have reduced net productivity from increased drought conditions. This study looks at how the gross primary productivity (GPP) of a stand composed of primarily chamise, redshanks, and desert ceanothus compares to the total net ecosystem exchange (NEE) found with eddy covariance towers. We found that chamise appears to contribute the most to the stands (r = 0.33), compared to the other species. The soil moisture in the stand controls both GPP and NEE while air temperature only shows significance in stand fluxes. Further research is needed to look at all the components of respiration and compare the derived values to the NEE.