Studies on structure in plant communities. VI. The significance of pattern evaluation in some Australian dry-land vegetation types

Abstract

The analysis of density data from a variety of Australian dry-land vegetation types provides evidence of widespread randomness when the component distributions are compared with a Poissonian model. While such randomness may be reflecting traditionally held beliefs concerning structure in colonizing and "relict" populations, randomness may develop as a result of a differential elimination of individuals between high and low density phases in an originally patterned population. It is suggested that structure in vegetation cannot be estimated reliably by simple observation alone, and this statement is evidenced by the ubiquity of random (and to a lesser extent contagious) distributions which are found in Australian dry-land communities, in contradistinction to the widely held view that such distributions are necessarily essentially regular in their character.