Mgidi Theresa N, Le Maitre David C, Schonegevel Lucille, Nel Jeanne L, Rouget Mathieu, Richardson David M
Natural Resources and Environment, CSIR, Stellenbosch, South Africa.
J Environ Manage. 2007 Jul;84(2):173-87. doi: 10.1016/j.jenvman.2006.05.018. Epub 2006 Oct 25.
Plant invasions are a serious threat to natural and semi-natural ecosystems worldwide. Most management-orientated research on invasions focuses on invaders that are already widespread and often have major impacts. This paper deals with "emerging" invaders-those alien species with the potential to become important problems without timely intervention. A climate matching procedure was developed to define areas of South Africa, Lesotho and Swaziland that could be invaded by 28 plant species that had previously been classified as emerging invaders. Information on the location of populations of these species in the study area was combined with information on their distributions (as native or alien) in parts of Australia and the United States of America. These two countries had the best available distribution data for this study. They also share many invasive alien plant species with South Africa. Climatic data obtained for weather stations near points of known occurrence in these countries were used to define the climatically suitable areas for each species in the study area. Almost 80% of the remaining natural environment in southern Africa was found to be vulnerable to invasion by at least one of these species, 50% by six or more and 24% by 16 or more species. The most vulnerable areas are the highveld grasslands and the eastern escarpment. The emerging invaders with the greatest potential range included Acacia podalyriifolia and Cortaderia selloana. The globally important invaders Ulex europaeus and Lythrum salicaria had a more limited invasion potential but could still become major invaders. There was no relationship between the extent of the climatically suitable areas for the different species and an expert ranking of their invasion potential, emphasising the uncertainties inherent in making expert assessments based on very little information. The methods used in this analysis establish a protocol for future modelling exercises to assess the invasion potential of other emerging invaders.
植物入侵对全球的自然和半自然生态系统构成了严重威胁。大多数以管理为导向的入侵研究都集中在那些已经广泛分布且往往具有重大影响的入侵物种上。本文探讨的是“新出现的”入侵物种——那些若不及时干预就有可能成为重大问题的外来物种。我们开发了一种气候匹配程序，以确定南非、莱索托和斯威士兰可能被28种先前被归类为新出现入侵物种的植物入侵的区域。这些物种在研究区域内的种群位置信息，与它们在澳大利亚和美国部分地区的分布信息（作为本土物种或外来物种）相结合。这两个国家拥有本研究可获取的最佳分布数据。它们还与南非共享许多外来入侵植物物种。利用在这些国家已知出现地点附近的气象站获取的气候数据，来确定研究区域内每个物种的气候适宜区域。结果发现，南部非洲近80%的剩余自然环境易受到这些物种中至少一种的入侵，50%易受到六种或更多物种的入侵，24%易受到16种或更多物种的入侵。最脆弱的区域是高地草原和东部悬崖。潜在分布范围最大的新出现入侵物种包括澳洲相思和蒲苇。全球重要的入侵物种欧洲荆豆和千屈菜的入侵潜力较为有限，但仍有可能成为主要的入侵物种。不同物种的气候适宜区域范围与专家对其入侵潜力的排名之间没有关联，这凸显了基于极少信息进行专家评估时固有的不确定性。本分析中使用方法为未来评估其他新出现入侵物种入侵潜力的建模练习建立了一个方案。
