Biotic disturbance and vegetation dynamics

The growing interest among ecologists in the influence of disturbances on community organisation is a logical consequence of the inadequacies of traditional equilibrium models in ecology. The current challenge is to obtain adequate characterisation of 'disturbance regimes' as a necessary precursor to the development of truly predictive models of vegetation dynamics. Thus, efforts are currently underway to quantitatively characterise the disturbance regime of numerous landscapes in terms of disturbance area, frequency, spatial distribution, return interval, predictability, and magnititude. Methodologies for obtaining these kinds of data are discussed and examples of their application in the central Rocky Mountains and northern Patagonia are described. In the former area, the dominant disturbances are fire and lethal insect epidemics, while in the latter fire and introduced large. mammals are the main agents of disturbance.