By Megan Gaitan and Julianne Bradbury
What, exactly, is the difference between “ecology” and “restoration ecology?” Where does one end and the other begin? Students in two Sonoma State University courses by those titles are discovering the differences, the similarities, and the joys of both concepts. In a shared field trip to Tomales Point at the Point Reyes National Seashore, the overlap between these two ideas were explored in a most dynamic and breathtaking context.
The Wonders of Tomales Point
Dr. Hall Cushman, instructor of the Ecology course, and Wendy St. John, co-instructor of the Restoration Ecology course, were the principal guides for the excursion. Additional leadership and interpretation was provided by Caprice Lee and Eric Cecil, both graduate students under the direction of Dr. Cushman, and instructors of the laboratory sections for the ecology course. This dedicated and knowledgeable team led roughly sixty students on a four hour tour, describing the land use history and vibrant ecosystem at this 2500 acre federally designated wilderness area.
A highlight of the day was the sight of Tule elk (Cervus canadensis nannodes), charismatic herbivores that were once almost hunted to extinction, but now grace this rugged area in relative abundance. Prior to the advent of the gold rush, populations of this California endemic species were estimated at around 500,000, but following the huge influx of miners (who were also hunters) in the second half of the nineteenth century, only 10-100 individuals were left. In 1978, California Fish and Wildlife (then “Fish and Game”) reintroduced Tule elk in 23 areas, including Point Reyes. Populations grew exponentially following reintroduction until 1998, when growth plateaued – since then the Tomales Point population has typically fluctuated between 400 and 600 individuals.
A prominent feature of the landscape is a set of 24 research plots; these plots were established by the National Parks Service and U.S. Geological Survey eighteen years ago, and are currently in use by Dr. Cushman’s graduate and undergraduate students. 12 of these plots serve as exclosures (fenced plots designed to prevent entry) for the Tule elk. The remaining 12 plots allow the elk free access, and serve as control plots to help researchers examine how these large herbivores impact the plant and animal communities at Point Reyes. For instance, Eric Cecil has sampled the invertebrate animals (insects, spiders, and other creepy-crawlies) with contraptions called “pitfall traps” in both types of plots to see how elk grazing changes the number of species and size of populations of these little critters. Caprice Lee performs similar studies on plant communities, and Vanessa Dodge, another one of Dr. Cushman’s graduate students, examines potential impacts on soil characteristics.
Research in the Field
After a great introduction to the study system we hiked our way up the Tomales Point Trail. Not far from the parking lot, though, was a small exclosure experiment being conducted on Monterey Cypress trees to protect them from herbivores. We paused for a description of this species that has historically been used as a windbreak to provide protection from the harsh elements that exist on the coast. However, ecologists see this non-native, invasive species as a threat to biodiversity here in the system. Cultural values that challenge ecological views of this tree reflect much of what we’ve learned this semester about different interests and decision making in restoration.
We continued on to our lunch break and quickly began collecting data. We first split up into six groups – 3 in an area heavily dominated by coyote brush (Baccharis pilularis) (high) and 3 in the dry, less populated Lupine (Lupinus arboreus) area (low). In these groups our objectives were to take true counts of dung and shrubs present in a 25 m x 5 m belt as well as measure the percent cover. True counts were taken by walking through the belt and recording the exact number of shrub species or dung piles present in the area. Percent cover was estimated by totaling the length of shrubs touching both reel tapes in 1 belt, dividing by the total area and multiplying by 100 to get a percentage.
We completed this procedure for 3 different plots we randomly selected in our given areas. Once all six groups were finished we graphed our data on a whiteboard to see the varying effects of tule elk in the different habitats. Plotting the number of dung per plot by percent cover for high versus low presented differing results. The high area had a trend that demonstrated low dung counts associated with more cover. The low plots did not have any general trends.
After seeing the graph displayed we hiked back to the vans and headed home. The excursion was a great introduction to sampling methods and research in the field. This exposure was greatly beneficial for all of us that attended and definitely gave us a new perspective in looking at field methods.