Alliances and guilds (was: Semiological Issues of Permaculture)
sustag at tinet.ie
Sat Aug 7 05:15:01 EDT 1999
Botanists and ecologists in Central Europe and in many other countries would be
familiar with phytosociology which defines plant assemblages on the basis of
their floristic composition (plant communities). Phytosociological methodology
was pioneered by J. Braun-Blanquet in the middle of this century.
The fundamental abstract unit in the hierarchical classification used in this
approach is the statistically defined *association*. Associations are grouped
together successively into alliances, orders and classes. Sometimes formations
are used as the highest syntaxonomic level. The taxa (units) are named in Latin
ending on ~etea (class), ~etalia (order), ~ion (alliance) and (with few
exceptions) ~etum (association).
An example for such a hierarchie:
Formation: Vegetation composed chiefly of shrubs and bushes
Class: Thornbush class (Rhamno-Prunetea)
Order: Prunetalia spinosae (Character species include i.a. Prunus spinosa,
Crateagus monogyna, Rhamnus catharticus, Euonymus europeaus, Cornus
Alliance: Rubion subatlanticum (Diagnostic species: Rubus spp., Sedum telephium)
Association: Primulo-Crataegum (Diagnostic species group: Crataegus monogyna, C.
laevigata, Rubus spp., Prunus spinosa, Rosa canina, Rhamnus cathartica,
Obviously there are other classes, orders, alliances and associations within
this formation and there are many more formations.
The details as to how these taxa and their suites of character species,
differential species and diagnostic species are arrived at would fill a book,
but maybe this explains why there are so many terms floating around. Also, while
this approach is widely used, it is not universal. Great Britain, for example,
has its own system and in the US maybe other appoaches are used again.
Applied phytosociology is an excellent tool for the field ecologist and has many
uses in conservation management. Since it does not only deal with natural
vegetation but also with e.g. forest or agro-ecosystems the understanding of
which species are likely to occur together under given circumstances combined
with a knowledge of successional development of vegetation can be a useful tool
for designing plant communities in PC systems much as in the way described by
My 2 cents worth.
Dipl.-Ing. TU Landschafts- und Freiraumplanung
mailto:sustag at tinet.ie
EN-DE-EN Naturschutz, Landschaftsplanung, Landwirtschaft
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