干旱区生态环境知识资源中心

A growing number of scientists now argue that cactus pears can make an important contribution to economic development in and and sub-arid lands. But others highlight instances where alien Opuntia have become serious weeds. This paper demonstrates the importance of bringing these two literatures into dialogue by exploring the complex and rather ambivalent consequences an introduced Opuntia had for Madagascar's and deep south. While the plant came to play a key role in local agro-pastoral economies, it also appears to have become invasive and difficult for people with limited resources to control. It is possible that by the early twentieth century it was threatening local bio-diversity. The paper argues that future policy recommendations regarding Opuntia introductions need to be informed by research that takes account of both the benefits and the risks, as well as the social and cultural values which shape how local communities perceive risk and evaluate costs. Further research is required into the conditions under which cactus pears become invasive. In particular, better understandings should be developed of the impact of alien Opuntia species upon patterns of vegetation sequence in highly specialised and land plant communities under specific social management systems, particularly swidden fallow cycles of different lengths.