Chapter Of The
By: John Sawyer
The release of the Manual of California Vegetation heralded a new state-wide perspective on vegetation classification. The premise of the book - all vegetation can be quantified based on cover and composition of plant species, yielding a uniform defensible definition of vegetation units - has proven to be very useful throughout California and the rest of the Nation. The Manual of California Vegetation has become the standard reference on California vegetation and has been adopted as the standard approach to classifying vegetation statewide.
As writing goes forward on the second edition of the book, revisions are being made to all descriptions. One of the most important aspects of the revisions includes geographic updating. At this time only about 20% of the state's vegetation is being mapped at the series level. Although the value of statewide, series-level mapping is enormous, there has been no mandate to produce a detailed California vegetation map. Thus, work proceeds in a piecemeal fashion and the entire state may take many years to be covered. In lieu of a California series-level vegetation map, we are seeking information on specific locations of all series based on geographic subdivisions known as ecological subsections.
In the revised edition of the Manual of California Vegetation, the existing "modified Jepson" ecoregional geographic scheme will be replaced with a more standardized and accurate ecoregional geography with the "ecological subsection" as its basic unit. Ecological subsections are defined by a combination of geology, soils, climate, and potential vegetation. They are intended to be used as ecologically-based units of conservation and natural resource planning (Bailey 1995). As with the CNPS vegetation classification concept of "series", ecological subsections are a hierarchical entity within a standardized classification of ecological units (Ecomap 1993).
Subsections are, like series, at the mid-level of their respective classification. However, they are not the same as a vegetation unit. California's subsection boundaries have been developed by a team of soil scientists, geologists, physical geographers, and vegetation ecologists. The unit boundaries are defined from a combination of relatively coarse-resolution geology, soil, climate, and vegetation. Maps (Goudey and Smith 1994) and a physical description of each (Miles and Goudey 1997) have been published.
The vegetation portion of a given subsection description was written based on inquiries made of vegetation experts statewide. However, much about the geography of vegetation remains uncertain in this state. There are remote areas and little-visited areas of private land. In addition, we are working with a new classification, its parameters largely untested. Thus, concepts of distributions and how the series vary geographically are often sketchy. To obtain more accurate understanding of the distribution of the vegetation types nothing short of systematic inventory will suffice.
CNPS and other volunteer organizations can greatly advance the current distributional understanding of vegetation. We have a strong need to verify locations of vegetation units and more general information about their composition. This information will feed into the geographic descriptions in the Manual of California Vegetation and will also be depicted on the geographic interface of the subsection map viewable on the Manual of California Vegetation website (http//:davisherb.ucdavis.edu/cnps Activeserver/index.shtmll). It is the next best thing to having a complete state-wide series level vegetation map.
Why do we need to know about the distribution of vegetation?
The Plan for Use
The North Coast chapters work will provide us with some distributional information to update the location of series for the second edition of the book. We envision the effort in the form of a "series-a-thon" to be held on April 24, 1999, where groups would work together in selected ecological subsections of their choice to gather distributional information on its vegetation. The efforts would be concentrated over a day with the ending session where all participants would collate and share their information. At the same time, this volunteer-based geographic inventory of series will provide information on new vegetation types and modifications to the existing vegetation classification and keys based on their extensive use by CNPS volunteers. In this way the keys and descriptions will be improved and potentially, new types of vegetation will be recognized, which will be described in the second edition.
The data collected will be entered into a computer database, already set up to inventory the location of series by each ecological subsection. We will add to a database that was developed to populate the CNPS series by ecological subsection web map and will add fields called "date of entry" or "field verification date." This new information will be directly linked to a digital map of ecological subsections now available on our website. The information will be added to the second edition of the Manual of California Vegetation.
Description of Protocol
This protocol will give anyone the basic understanding of this exercise. It is more an introduction to the methods and anticipated results of a series-a-thon. Viewing the landscape as a series of vegetation types is an effective and enlightening perspective for an ecological understanding of any area. It initiates thinking about the environmental controls over the species of plants - slope changes, aspect differences, soil types, geology, or local microclimates. All have a role to play in the pattern of existing vegetation, as do physical processes such as fire history, flooding, and other human-mediated, animal, or natural disturbances.
Bailey, R.G. 1995. Ecosystem geography. Springer-Verlag. New York, NY.
ECOMAP. 1993. National hierarchical framework of ecological units. Unpublished administrative paper. USDA Forest Service. Washington D.C.
Goudey, C.B. and D.W. Smith 1994. Ecological units of California: subsections. A colored map at 1:100,000. USDA Forest Service, Pacific Southwest Region, San Francisco, CA. Available from the Regional Forester, USDA Forest Service, 630 Sansome Street, San Francisco, CA 94111
McNabb, W.H. and P.E. Avers. 1994. Ecological subregions of the United States: section descriptions. USDA Forest Service Publication WO-WSA-5. Washington D.C.
Miles, S,R. and C.B. Goudey. 1997. Ecological subregions of California: section and subsection descriptions. USDA Forest Service, Pacific Southwest Region Publication R5-EM-TP-005. San Francisco, CA. Available from the Regional Forester, USDA Forest Service, 630 Sansome Street, San Francisco, CA 94111.