Community Classification and Nomenclature
T HREE Community Classification and Nomenclature TODD KEELER-WOLF, JULIE M. EVENS, AYZIK I. SOLOMESHCH, V. L. HOLLAND, AND MICHAEL G. BARBOUR Grass-dominated vegetation covers approximately one-fourth Mueller-Dombois and Ellenberg 1974). In addition, each type of California’s area, and it is well known that virtually all of exists in a precontact and a postcontact condition. Four of it has been significantly modified by the invasion of natural- them are regional in distribution, but serpentine grassland is ized annual and perennial grasses and forbs. Less commonly azonal and not limited to a single geographic region. understood is the fact that this type conversion resulted in Before we tour these major types, we offer several defini- very few extinctions. Bartolome et al. (in press) concluded tions. These definitions are largely our own creation, because that—although local extirpation, reduced abundance, and the literature is so inconsistent in their treatment. range retraction characterize the status of the once-dominant native taxa—only a few species have retreated to the point of Vegetation and Community Type Definitions complete extinction. Only four of the 29 taxa presumed to be extinct throughout all of California could have once been Grassland is vegetation that belongs to the Herbaceous For- components of the valley grassland (CNPS 2001). Native mation Class, defined by Grossman et al. (1998) as “Herbs species remain rich in number, even if individually their cover (graminoids, forbs, and ferns) dominant (generally forming at is low. In some areas, their cumulative cover is greater than least 25% cover; trees, shrubs, and dwarf shrubs generally less that of the exotics.
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