|Rachel displaying proper bird handling.|
Rachel’s Master’s Thesis research studies the impacts of an invasive weed species, Lepidium latifolium, on marsh food webs. For her, ‘the field’ is a brackish marsh on Rush Ranch Open Space Preserve, a component of San Francisco Delta Estuary. She measures environmental parameters of the vegetation, in addition to sampling birds (via blood and feathers), invertebrates (bird food), and plants (invertebrate food) for stable isotope analysis.
More fancy science talk. Stable isotope analysis. This technique follows the notion that you are what you eat. Isotopes of certain elements (Carbon and Nitrogen, in Rachel’s research) get passed along when organisms are consumed and become incorporated into the predator’s tissue. Rachel can compare the plant, bug, and bird isotopes to figure out the food web.
|Marsh at Rush Ranch Open Space Preserve. White
plants are the invasive weed species she studies.
Photo Credit: Christine Whitcraft
Rachel’s field component in the marsh requires a seven hour drive into northern California. With drives that long, she has to concentrate her efforts for the weekends. A typical outing includes measuring environmental parameters of vegetation, and the aforementioned sampling for isotope data. She has modified a leaf blower so now it serves as a ‘bug vacuum’ for collections. Her lab work consists of lots and lots of processing. According to Rachel, “It’s just the right amount of mix between the two, by the time I’m tired of being up at 4 am, it’s time to be in the lab for a while. When I’m sick of being indoors it’s time to go out to the field again.” In addition, she must also devote several hours per week with other graduate students in her lab working on the restoration efforts mentioned yesterday.
Do you know of any invasive species in your area?
Have they caused problems for the natural flora and fauna?