A comprehensive scheme is presented which provides qualitative models of vegetation dynamics in communities subject to recurrent disturbance. The scheme has been derived to deal mainly with terrestrial communities dominated by higher plants, but may be more widely applicable.
The scheme utilizes a small number of life history attributes termed ‘vital attributes’ which pertain to the potentially dominant species in a particular community. Three main groups of vital attributes are recognized, relating to the method of persistence of species during a disturbance and to their subsequent arrival, to their ability to establish and grow to maturity following the disturbance, and to the time taken for them to reach critical stages in their life history.
In the application of the scheme, each major species is first categorized into a ‘species type’, determined by its specific attributes in the first two vital attribute groups. The interaction between various species, based on their species types and life stage attributes, then yields a replacement sequence which depicts the major shifts in composition and dominance which occur following a disturbance. Although 30 species types are recognized, only 15 distinct patterns of behaviour are displayed in replacement sequences.
Examples of replacement sequences for two different forest communities are provided.
The degree to which vital attributes are robust properties of a species is explored in relation to different disturbance frequencies and intensities, and to the seasonal time of disturbance.