The individualistic nature of plant community development

Summary

A body of anecdotal and experimental evidence raises questions about the common model of plant community succession, in which each temporal vegetation stage facilitates the development of the next stage. Several lines of evidence are discussed which emphasize the individualistic, independent nature of plant community development:

• 1) There are a number of instances of anamolous behaviour of ‘pioneer’ or ‘early successional’ species;

• 2) In shallow marshes, vegetational change is the result of the interaction between the stored ‘seed bank’ of the the ecosystem and the fluctuating water regime;

• 3) On abandoned coal spolis, vegetational composition and structure are almost entirely accounted for by substrate conditions rather than age differences of the spoils;

• 4) In overgrazed natural grasslands, adjacent to ungrazed areas, revegetation is primarily by vegetative reproduction of the native species creeping in from the edge as a whole vegetation complex, rather than seeding throughout in stages.

Therefore, plant succession can be interpreted as an individualistic result of the interaction of disturbance (both kind and severity) and the predominant reproductive life histories of the plant species.

It is suggested that future research efferts to understand vegetational change should be directed to the interactions between seed dynamics, asexual/sexual life histories, and microsite environmental variation.