Introduction

We have previously discussed the historical, socio-economic, and ecological aspects of introduced plants. However, land managers and environmental consultants are faced with developing plans and procedures for responding to invasive plants. For them conservation and restoration are the goals. Some researchers would, no doubt, argue that a clear economic cost–benefit analysis of different strategies is essential prior to embarking on a weed control program (e.g. McNeely 2000, Naylor 2000). However, even with such an analysis, success cannot be guaranteed (Rea and Storrs 1999). Science can help to inform management decisions, but ultimately all such decisions about our environment are driven by political imperatives, social concerns and economic constraints. Although the latter factors often dominate, management decisions should still be based on good ecological principles when these are well established and requires, at the very least: (1) sound, defensible science, and (2) education about the issues.

In this chapter we summarize the techniques and programs that have been used to deal with introduced species, and the processes by which habitat managers and researchers may evaluate these programs. We also look at how management strategies have been developed or are developing at international, national, regional, and local scales. In this chapter we broaden our outlook to include considerations relating to non-indigenous species that are not purely ecological. We consider the perceived benefits of introduced plant species, as well as the costs, benefits and outcomes of large-scale and small-scale removal programs for invasive species.