Experimental Design at Point Reyes

By Keith Wellstone and Eric Fuss

During this field trip, Sonoma State’s restoration ecology, and ecology classes learned about experimental design through the Pearson’s Point Ranch Elk reintroduction. Led by Dr. Hall Cushman, the class was introduced to the details of the experiment, and even got a chance to practice field sampling methods.

Pearson’s Point Ranch is a historical ranch under protection of the National Park Service. This site is unique because the goal of protecting the property was not only to protect the natural landscape, but to preserve the settlement and ranching history as well.

Historically, the Tule elk population in California’s central coast valley peaked at 500,000 individuals. After the gold rush, they were hunted nearly to extinction; it was thought that between 10-100 individuals remained. Efforts to reintroduce Tule elk started in the 1960’s, and have been very successful.

Dr. Cushman explaining the experimental design used in the Tule elk reintroduction project

Dr. Cushman explaining the experimental design used in the Tule elk reintroduction project

The study we learned about was a multi-year exclosure experiment to study the influence of introduced Tule elk on community composition in a coastal California grassland. The design contains 24 plots within 3 habitat types; shrub-grassland, intermixed grassland with Coyote bush, and intermixed grassland with Lupin. The plots were grouped in pairs, with 12 fenced plots to exclude Tule elk. These plots serve as the experimental group, while the unmanipulated plots serve as the control group. Three of Dr. Cushman’s graduate students shared their own research objectives while we were on site. Cody is using this design to study the effects of the invasive Velvet grass (Holcas lanatus) and its effect on population response of native perennials. Eric is studying the effects of Tule elk on arthropod presence and abundance, and Vanessa is studying the influence of Tule elk on soil nutrient composition.

Baccharis covered landscape

Baccharis covered landscape. Photo: Eric Fuss

Lupinus dominated landscape

Lupinus dominated landscape. Photo: Eric Fuss

During this field trip we also learned some useful sampling methods. The class broke into groups and sampled along 25 meter transects recording percent cover of Baccharis/Lupin, and elk dung abundance. The class used 1 m x 1 m quadrats to quantify dung abundance.

Angelica sampling using a quadrat

Angelica sampling using a quadrat. Photo: Keith Wellstone

 

Keith plots the data his group collected while sampling the transects.

Keith plots the data his group collected while sampling the transects. Photo: Eric Fuss

Dr. Hall Cushman explains a graph that plots the relationship between brush cover and the presence of Tule Elk dung.

Dr. Hall Cushman explains a graph that plots the relationship between brush cover and the presence of Tule Elk dung. Photo: Eric Fuss

Overall, the field trip was a great introduction to field research. The class learned about various field methods had some fun, and enjoyed a beautiful day in one of the most amazing locations on the planet!

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