Vegetation Committee

On October 21 Julie Evens and Anne Klein, both State CNPS vegetation ecologists, led a workshop on vegetation sampling techniques for members of the East Bay CNPS Vegetation Committee. We learned about the history of vegetation sampling in the US and California, the goals of data collection and vegetation classification, and how to carry out the CNPS Releve vegetation sampling protocol. The workshop took place on the south side of Mt Diablo, near Knobcone Point. About 1.5 miles from the Curry Point trailhead after you pass through grassland and oak woodland, the Knobcone Point Trail climbs along the ridge and you enter chaparral. The trail is lined with both Mount Diablo manzanita (Arctostaphylos auriculata), which has grayish, hairy leaves with a heartshaped base, and common manzanita (Arctostaphylos manzanita), which has bright green leaves. Mount Diablo manzanita is listed in the CNPS Inventory of Rare and Endangered Plants as List 1B (rare, threatened, or endangered in California and elsewhere) and is known only from Contra Costa County in the vicinity of Mount Diablo. Mount Diablo manzanita blooms from January to March with gorgeous light pink flowers, and the Knobcone Point Trail is an excellent place to see this color display.

Just downslope to the south of the trail, there is a section of chaparral that was probably burned in the last 5 years. Black-charred skeletons of common manzanita are present and there is thick undergrowth of shrubs that resprouted from root crowns or germinated from seeds after the burn. We set up a circular 400 square meter plot in the burned chaparral and collected data on the elevation (1,640 feet), slope, aspect, GPS location, and soil. We estimated the percent cover of all the species found in the plot. The plot was dominated by chamise (Adenostoma fasciculatum) and buckbrush (Ceanothus cuneatus) with subdominants of yerba mansa (Eriodictyon californicum), black sage (Salvia mellifera), toyon (Heteromeles arbutifolia), and common manzanita. Based on the data we collected, we assigned the name “chamise (Adenostoma fasciculatum) and buckbrush (Ceanothus cuneatus) alliance” to the vegetation type. One thing we learned is that it is easy to overestimate percent cover. For example, even though chamise and buckbrush were the dominant shrubs, they only had 15% and 28% cover respectively. Also at first glance, the vegetation looked very diverse, but upon closer examination of what plant species were there, it became clear that it was dominated by only two species. The data we collected will be incorporated into a statewide database used to classify, map and track vegetation types. The weather was gorgeous, the black sage smelled wonderful, and we all had a good time. Special thanks to Julie and Anne, who traveled all the way from Sacramento to lead the workshop.

The Vegetation Committee will be going out into the field and collecting vegetation data in 2007, mostly on weekends. If you are interested in helping to collect this valuable information, please contact me via email at erinmcd2004@yahoo.com.

Photo Info: From left to right: Sue Wilson, Erin McDermott, Lech Naumovich, Heath Bartosh, Chris Thayer, Anne Klein (standing), Gregg Weber. Photo by Julie Evens.

Erin McDermott

The Vegetation Committee collects information about plant communities in Alameda and Contra Costa counties. When most people think of vegetation, they think of general groupings such as chaparral, oak woodland, riparian forest, or grassland. While the grouping of plant communities into these broad terms is a good first step, these names do not give us enough information. For example, chaparral can be used to describe any type of vegetation dominated by evergreen shrubs with leathery leaves, whether it is dominated by oaks, manzanita, ceanothus, or chamise. Information about the plant species present in the vegetation and their abundance is more meaningful. This information is used for conservation planning, identifying rare vegetation types, and assessing habitat for sensitive plant and animal species. If everyone uses the same method for collecting information about the vegetation, we can analyze the data correctly. Otherwise, we are comparing apples and oranges.

CNPS uses the same approach for vegetation data collection as A Manual of California Vegetation (Sawyer and Keeler-Wolf 1995). It is based on a hierarchical classification similar to that used in floristics, where species are grouped into genera and then families and then orders and so on. In vegetation classification, the association type is the most specific and the most useful category.

An example of a hierarchical classification of a vegetation type: Physiognomic types: Riparian and Bottomland Habitat General habitat type: Riparian Forest and Woodland Alliance Type: Red Alder (Alnus rubra) Association Type: Red Alder/ Arroyo Willow (Alnus rubra/ Salix lasiolepis).

The East Bay Vegetation Committee collects field data following a standard CNPS protocol. The data will be used in updating future editions of the Manual of California Vegetation and towards determining priorities for protection and restoration in the East Bay. The Vegetation Committee will be going out in the field and collecting vegetation data in early 2007, mostly on weekends. If you are interested in helping to collect this valuable information, please contact me via email at Email Erin.

Erin