UNDERUTILIZED CROPS AND INVASIVE SPECIES – UNDERSTANDING THE LINKS

A significant number of plants on lists of underutilized crops are also on lists of invasive species, and these can have massive negative impacts on rural livelihoods, the environment and biodiversity. Thus, professionals involved with underutilized crops, and especially those considering introductions to new areas, must be aware of the potential invasiveness and take the necessary steps to address it. In contrast, those involved with invasive species must also note the potential uses of invasive plants, and acknowledge the emerging concept of ‘control by utilization’ as a means of management. This paper presents examples of good, bad and innovative practices in reducing risks and impacts of plant invasion, and areas for further development between underutilized crops and invasive species. Some important aspects include highlighting whether plants are recorded as invasive. Also, prior to any introduction, even if limited and restricted to a research station, a weed risk analysis must be conducted. Several models are available and in current use which result in ‘accept’ (introduction), ‘reject’ or ‘further research required’. Even if accepted, some species only become invasive after a certain time, possibly released by triggers, thus a continual monitoring programme should be established and a set of actions agreed with if the plant begins to spread. Such surveillance should also be implemented for other underutilized crops known to be invasive elsewhere as they may be ‘sleeper weeds’, and management plans should be drawn up. All this may appear over-cautious, but such risk reduction involves insignificant resources compared with reducing the impacts once a plant has become invasive. It is clear that there are many mutual benefits to be gained by promoting further exchanges between professionals working with underutilized crops and those working with invasive plants, and such initiatives should be encouraged.