Colonisation theory and invasive biota: The great fish river, a case history.

There is worldwide concern over the impact assessment and management of altered ecosystems. Increasingly, attention has been focussed as much on the properties of invasive biota as on physical and chemical degradation. Successful management of such impacted systems requires a clear understanding of the status and behaviour of introduced species. Thus, with emphasis on aquatic systems, it is the purpose of this paper to (a) evaluate the characteristics of successful invader species, and (b) identify those properties of a habitat which enhance its susceptibility to invasion. In this regard, a case study of the Great Fish River in South Africa is presented, and important terminology defined.