"Plant Communities" and the Three Major Types of Plant Cover
The three major types of plant cover are:
- Tree-dominated (subdividable according to relative abundance of conifers and angiosperms and according to dominant species). On rock or good soil (acid to neutral).
- Shrub-dominated (subdividable into “chaparral” and “scrub” of various kinds) Generally on hotter/drier sites than trees (e.g. S slopes), usually on slopes, usually on poor soil or bare rock or alkali or acidic substrates.
- Herb-dominated (i.e. grasslands, flower fields, etc) (subdividable into many types). On sites too dry, poor (sand or shallow soils or serpentine), or seasonally-waterlogged for shrubs or trees to survive).
Any given landscape may be—and very often is—a complicated mixture of these.
Sometimes the relative dominance of trees vs. shrubs vs. herbs has much to do with the recent management history, disturbance, fire etc. In fact, every detail of the species composition and other aspects of the vegetation at a given site is a reflection of the site’s recent history.
All three general plant-cover types can be/have been subdivided ad nauseam according to any number of more or less ______ criteria.. [Give examples of the various systems that are or have been in vogue, and the relative value of the whole “plant community” concept, its pros and cons and absurdities.]
The usefulness of the whole “community” concept is open to question. It can have some predictive value. But I think too much credence is given to these variously described assemblages as real, functioning entities of a sort, as if they were actual organisms. The same goes for the concept of “ecosystems” as if they were actually some sort of self-contained, organismal entities operating more or less independently of other such entities.
Bring up idea of a different, more flexible/fluid, non-hierarchical way of describing vegetation that is at once simpler and yet more specific than other approaches; a more down-to-earth, commonsensical approach that needs no fancy terminology and anyone can understand/visualize easily.
