The problems of prediction and scale in applied ecology: the example of fire as a management tool.
This paper serves as a brief introduction to a set of four papers on the large-scale effects of fires as management tools. Two papers in this profile deal with the effects of fire on North American grassland ecosystems, although with slightly different perspectives. The third paper also considers the interaction between fire and trophic interactions, in this case how fire interacts with biocontrol to reduce the density of a problem weed. The final paper explores some of the wider ecosystem consequences of using fire as a management tool in southern African savannas. Ecological interactions are key to understanding the effects of fires. Species respond differentially to processes such as competition and herbivory, as well as to fires. This means that community composition may change substantially with changing frequency of fires. The studies highlighted in this profile reinforce the role of fire in modulating the frequency of invasion of alien species in a range of ecosystem types. In two of the studies, alien species were superior competitors to native ones in the absence of fires, but unable to regenerate following fires. In the future, it will be necessary that the results of short-term experiments are integrated with long-term observational data and with theoretical models to predict long-term dynamics. We discuss how this may be done. Synthesis and applications. The studies of the management of ecosystems using fires as a tool are prime examples of the application of ecology. In addition to measuring the proximate effects of such management using experiments, it is necessary to understand in detail the effects of fire on the underlying interactions between species, and feedbacks between different components of ecosystems.