Vegetation Classification
| Vegetation Classification—An Unvarnished Perspective |
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Classification
of vegetation has a long and colorful history in such disciplines as Ecology
and Plant Geography, perhaps in its earliest forms predating these fields.
It remains a popular and persistent field of scientific inquiry (and of
invention of hierarchical schemes of community organization ad nauseam). The latter is attested to by the latest effort of the
Ecological Society of America and The Nature Conservancy to "re-invent"
a taxonomic hierarchy of North American vegetation-perhaps by coining
new terms for existing units—even though much of the natural flora has
been largely modified or even destroyed by human activity. The "been
there; done that" (already and repeatedly) history of vegetation
classification has itself been reviewed, at least in part, by several
workers. Readers desiring an unabridged account are referred to Whittaker
(1962), Shimwell (1971), and Mueller-Dombois and Ellenberg (1974). Current
classification "goings-on" can be found in contemporary Plant
Ecology texts (eg. Chapter 10 of Barbour et al., 1999).
Developing
still yet another vegetation classification scheme requires no experimentation
(in addition, it traditionally has often been descriptive and arbitrary).
Thus, such scholarship can be done "on the cheap" and without
career-threatening criticisms such as allegations of "pseudo-replication".
The net result is a mind-boggling array of "systems" among which
there is both much overlap and confusion. Much of this appears to result
from the plethora of units of vegetation and/or levels of organizational
hierarchy used to describe and imaginatively arrange the vegetation. Throughout
the long and tortured lineage of Vegetation Science systems (long before
this newer term), two of the surviving units and terms have been: 1)
Association
2)
Vegetation type (or some similar term meaning essentially the same
thing). Association
as a term (and probably the concept) is traceable to Friedrich Heinrich
Alexander von Humboldt, according to standard Plant Ecology texts (eg.
Daubenmire, 1968; Barbour et al., 1999). Vegetation type was attributed
to August Griseback by Braun-Blanquet (1932, p. 302), the latter of whom
warned readers to use the term "with caution". Association and
vegetation type date back to the Nineteenth Century and the founding fathers
of Plant Geography, and precise meanings of these two most enduring (and
probably most useful) terms for units of vegetation have eluded ecologists
ever since. This has been in spite of the fact that association was adopted
by the Third International Botanical Congress in 1910 as the official
term for the basic unit of vegetation classification (Daubenmire, 1968,
p. 27). Apparently,
ecologists, plant geographers, vegetation scientists, as well as ecological
practitioners like foresters and rangemen can agree on the validity of
these terms, just not where to put them in an arbitrary organization of
vegetation that extends from the broadest to the most restrictive floristic
unit. Hence the response is to create a "new" classification,
usually another elaborate scheme with many or most of the existing terms
rearranged, which of course portends to eliminate all the ambiguity of
all its predecessors. Fortunately
for practitioners and scientists in Range Management and Forestry, there
is no real need for all of these hierarchical levels and units for either
on-the-ground management or useful research that can be applied to this
management. The term and concept of vegetation type at the larger or more
general scale and that of range and forest site at the smaller, more restrictive
scale seem to have served these professions and related ones like Wildlife
Management adequately. To be sure, the politically correct (and expedient) high-profile members of these natural resource disciplines have attempted recently to soften the commodity and industrial-professional traditions that brought them into existence in the first place. For example, some within the Range Management profession object to such professional terms as range and the very symbol of our profession, the beloved Trail Boss. The "image" of "cowboy" or "livestock management" is somehow allegedly offensive to some folks and, by extension, interferes with "recruitment" to the profession and almost assuredly to membership growth in the Society for Range Management. (One suspects that the caduceus with its two snakes coiled around a winged staff would be equally repulsive, and a lot less representative, in symbolizing Medicine.) One apparent response to this deny-our-professional-heritage attitude was to supplant the term range site with ecological site (as if we manage "ecologicals" instead of ranges), but everyone knows that the "more ecologically friendly" ecological site and traditional range site are the same (Jacoby, 1989; Bedell, 1998). So there is no problem in communication, injured professional pride and reduced precision of language notwithstanding. |