Although biological invasions have rapidly become prominent environmental concerns in almost every part of the world, only a handful of countries are giving serious attention to the problem. The most focused research, planning, policy formation, and implementation of counter-measures is taking place in Australia, Europe (with marked variations between countries and regions), New Zealand, South Africa and the United States. At least there, perspectives have changed radically in the last few decades, from the consideration of single-species problems to the incorporation of invasive species as a complex component of global change requiring substantial investment at multiple scales of time and space. Yet, most developing countries lack the capacity even to deal with dramatic single-species problems, let alone to respond holistically to the escalating problems associated with invasions that demand expensive, multipronged, international efforts.

In this respect, there are several important international initiatives, including the Global Invasive Species Programme (GISP), the International Plant Protection Convention (IPPC), the Convention on Biological Diversity (CBD), and the South Pacific Regional Environment Programme (SPREP). However, much effort is wasted through a lack of cooperation, collaboration and integration, and in many cases, open rivalry exists between different agencies and groups involved nationally and internationally. There are at least some notable exceptions to this gloomy picture, which include the Nature Conservancy (a U.S.-based non-governmental organization), which leads in acquiring land, and supporting multidisciplinary research and control operations in conservation areas, in the United States, and elsewhere.

South Africa’s Working for Water programme, with its strong emphasis on multi-departmental involvement and international cooperation, and the Australian Cooperative Research Centre for Weed Management are others

The National Invasive Species Council of the US. is tasked with the production, every two years, of a National Invasive Species Management Plan, and a massive effort is now under way at every level in the United States (including work on prediction/ prevention, early detection, eradication, containment, management, restoration and education).

There is a particular emphasis in the management of plant invasions on prevention, early detection and/or eradication.

In the area of prevention, that is, the anticipation and interception of invasions, Australia, New Zealand and the U.S.A. are the only countries devoting even remotely appropriate resources to research, policy development and implementation.

Given the exponential increase of invasive species, it makes sense to focus effort on preventing the entry of known nvasive species and to maintain early arning systems to detect nascent nvasions of species that do gain entry.

There have been a few cases where very small populations of potentially invasive plants have been eradicated (that is, totally eliminated).  While eradication may be a sound goal for new and small invasions, it could be an illusory and costly objective for wellestablished mainland populations of invasive plants.