The vegetation at any particular location may be described in terms of the plant species present (from tallest trees to smallest herbs), and the relative ‘importance’ of each species based on a combination of abundance (number of individuals) and cover (how much of the area they occupy).
Plant species composition and relative importance varies across the landscape, and vegetation classification is an artificial framework used to subdivide and describe the patterns of composition and importance observed along complex continua of environmental and other gradients, including moisture, temperature, soil fertility and disturbance history. Because of the importance of plants to all other elements of biodiversity, vegetation classification units are commonly used as surrogates for broader biodiversity classification.
They identify and describe recurring patterns of native plant species assemblages in relation to environmental conditions; that is, sets of species that commonly occur together in association with particular combinations of soil, temperature, moisture and other factors.
PCTs fit within broader units known as vegetation classes. There are 99 vegetation classes representing broader-scale vegetation patterns across NSW. These in turn are nested into 12 vegetation formations at the top of the hierarchy. The two upper levels of the hierarchy are drawn from the independently constructed schema of Keith (2004) who described the native vegetation of New South Wales. See more at catalogue.nla.gov.au
Answers to common questions about plant community types can also be found at www.environment.nsw.gov.au