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Finding ‘Missing Link’ Between Vegetation and Carbon Sequestration

May and June 2015
Iryna Dronova

Although it’s been about two years since she started as a Delta Science Fellow, Dr. Iryna Dronova is still heavily involved in researching the vegetative cover of various wetland areas of the Delta as a way to help other researchers build models that will ultimately assist them in estimating the carbon sequestration potential across entire wetland landscapes.

“This kind of work has only been done sporadically in wetlands, so we spent a lot of time in the first year just learning which techniques worked better,” Dronova said. “Now I’m more confident on how to approach the field measurements and linking them to the NASA Landsat satellite imaging archives.”

Determining how much carbon can be taken up by Delta-area plants offers the region the possibility of becoming financially self-sustaining through the emerging carbon crediting market. The market allows entities with large carbon footprints to purchase credits from absorption areas like the Delta thereby mitigating their own carbon emissions.

As for NASA’s archival images, Dronova says they date back to the early ‘80s and are available to the research community for free. Combining her methodology research with more than three decades of satellite images allows her to review, and possibly even predict, long-range changes in the Delta’s complex land cover – in particular carbon absorbing vegetation canopies.

“Even though Landsat data has coarser resolution than aerial photography, we can use the images to predict and monitor wetland functional properties in different seasons and years. This information will facilitate other researcher’s models of carbon sequestration over a longer period of time.”

In essence Dronova’s work involves discovering the missing link that will help other scientists complete the analytical picture. She says there is also great interest in understanding how the vegetation canopy habitat changes over time, and how it can vary among different wetlands in response to human management and treatment or natural occurrences.

“The variable I’m studying measures the amount of cover in the canopies, which approximates the amount of shelter for migrating birds or more permanent Delta residents like the federally endangered Ridgeway’s Rail and salt marsh harvest mouse,” Dronova said. “The ability to create a long-range map of this landscape will improve our understanding of the habitat properties of plants as they relate to a diverse pattern of interaction including various other wildlife, human management and recreation, and maintaining ecological services associated with the animals in these wetlands.”

Dronova has recently moved from a postdoctoral researcher to an Assistant Professor position at U.C. Berkeley in the University’s Department of Landscape Architecture and Environmental Planning – a detour from her Delta Science Fellow activities. But she continues to be intrigued by the diversity and complexity of the Delta wetlands, which is why the research remains a vested interest and active area of her work.

“One of the most exciting things is the suite of new questions coming out of this project – questions that we’ll be investigating in the future,” Dronova said. “Eventually I’d like to utilize the entire Landsat archive of satellite images. Then I and other researchers could use these new maps for the modeling of carbon fluxes and habitat as well as improving their accuracy.

Coequal goals

The Delta Stewardship Council was created in legislation to achieve the state mandated coequal goals for the Delta. "'Coequal goals' means the two goals of providing a more reliable water supply for California and protecting, restoring, and enhancing the Delta ecosystem. The coequal goals shall be achieved in a manner that protects and enhances the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place." (CA Water Code §85054)