By Heidi Schindler, Megan Rosario and Megan Stock
On October 2nd, our Restoration Ecology class joined an Ecology class from Sonoma State University on a trip to Point Reyes National Seashore at the Tule Elk Preserve. The field trip was led by Dr. Hall Cushman and his graduate students currently studying the preserve, who provided information on the type of research they were involved in regarding the preserve. The purpose of this trip was to experience what type of work is involved when studying a restoration site and the type of research that has been done to accomplish a scientific study of ecology. We also performed a type of field method called transect sampling and created a quick data set and hypotheses based on our observations.
Our trip started with a quick historical overview of the preserve and then the type of research currently being performed by Dr. Cushman and his graduate students. Dr. Cushman began by telling the history of Tule elk. Due to hunting, the Tule elk population was reduced to about 100 individuals. A single rancher in the area protected the elk just on his land which were the last of the elk and single-handedly saved the Tule elk from going extinct. In 1978, 10 Tule elk were introduced in Tomales Point, did very well and experienced nearly perfect exponential growth until 1998. Since then, due to dry years and the drought, Tule elk have experienced a fluctuating population.
In 1998, scientists began to study the effects of Tule elk and vegetation. They found that the reintroduction of the Tule elk has had varying effects on this ecosystem. To explore the question of whether or not large mammals can be used to restore ecosystems was posed, a large scale experiment was initiated. It was created in a 100 acre area with 24 plots distributed under 3 habitat types (shrub-free grasslands, grasslands with coyote brush [Baccharis pilularis], and grasslands with lupines[Lupinus punto-reyesenis]), with one third of the experiment performed in each habitat type. They created fenced and non-fenced plots within each area to reduce bias. Dr. Cushman’s current research is on Tule elk and how their reintroduction has affected the ecology of the preserve.
Before we walked out to one of the nearby enclosures, a few of the graduate students at Sonoma State who have been working at the Tule Elk Preserve shared with us their ideas for their projects and what they were hoping to gauge as they conducted their individual research. One of the students focused on soil ecology within the reserve boundaries. She intended to analyze characteristics of soil such as soil compaction, water filtration through soil mediums, and nutrient abundance (just to name a few) and how the Tule Elk impact these aspects of soils. Another individual observed that a particular invasive plant species was preferred by the Tule Elk. This led her to the question; will this preferential feeding on this invasive plant species result in a phenotypic alteration of the vegetative species? Cody Ender will be looking into the effects that the Tule Elk have on Holcus lanatus, the invasive velvet grass. Generally the velvet grass is persistent in areas that have been subject to low grazing levels so with the fairly recent Tule Elk population increase, the velvet grass could substantially decline. This decline could potentially lead to the emergence of native vegetation by lessening the competition between the vigorous Holcus lanatus and native grasses. Cody’s study is similar to the research of Dr. Cushman and Brent Johnson; however, Cody will be analyzing more current conditions of the elk/Holcus lanatus interactions. The final research that was presented to us came from Eric Cecil. Eric would like to further his research on the Tule Elk Preserve by focusing on arthropods. He intends to shed light on whether or not arthropods are having a significant effect on the plant composition. He plans on manipulating plot areas within the preserve by excluding arthropods and comparing those exclusionary plots with plots that include the arthropods.
We sampled along several transects (as illustrated in the photos), and concluded that there was no correlation between shrub cover and the presence of dung. Overall we and our peers had a very educational experience from this field trip as well getting to enjoy the gorgeous Point Reyes vista. It was a valuable learning experience in understanding field techniques and the type of research that is done in restoration.