Predicting future threats to the native vegetation of Robinson Crusoe Island, Juan Fernandez Archipelago, Chile
Predicting future threats to the native vegetation of Robinson Crusoe Island, Juan Fernandez Archipelago, Chile
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DOI：
10.1111/j.1523-1739.2003.00173.x
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发表时间：
2003-12-01
影响因子：
6.3
通讯作者：
Stuessy, TF
中科院分区：
文献类型：
--
作者：
Dirnböck, T;Greimler, J;Stuessy, TF
胡安·费尔南德斯群岛是智利的国家公园和生物圈保护区，位于智利大陆以西700公里处。入侵植物物种对当地高度特有的植被构成了重大威胁，特别是在鲁滨逊克鲁索岛(Mas A Tiera)，那里有一个永久的定居点。我们使用历史和最近的植被图数据以及最近的植被点数据来重建自20世纪初以来岛上的植被变化。此外，我们使用带有环境变量或其替代变量(海拔、太阳辐射、地形相似指数、坡位)的Logistic回归模型来估计最严重入侵的潜在分布。当地植被受银杏、马兜铃、悬钩子和毛果的影响最为严重，导致山地森林和当地灌丛中特有植物的数量显著减少。原生森林已经减少了大约三分之一。受赤木通影响的面积由总岛面积的6.5%增加到14%。曾经稀有的Ugni molinae现在数量丰富(4.6%)，Acaena也是如此(11.9%)。80年前还不存在的悬钩子，现在覆盖了该岛约7%的表面。除悬钩子外，其余物种的分布均受环境因子的显著控制(p<；0.05)。根据红木通和毛木通的潜在分布推论，50%的山地森林可能被这些植物入侵或取代(概率为60%)。根据过去80年的入侵速度，如果保护措施不成功，还需要80年的时间。
The Juan Fernandez Archipelago, a Chilean national park and biosphere reserve, is 700 km west of continental Chile. Invasive plant species pose major threats to the native, highly endemic vegetation, especially on Robinson Crusoe Island (Mas a Tierra), where there is a permanent settlement. We used historical and recent vegetation map data as well as recent vegetational point data to reconstruct vegetational changes on the island since the early twentieth century. In addition, we used logistic regression models with environmental variables or their surrogates (elevation, solar radiation, topographic similarity index, slope position) to estimate the potential distributions of the worst invaders. Native vegetation has been affected most severely by Acaena argentea, Aristotelia chilensis, Rubus ulmifolius, and Ugni molinae, leading to a significant decrease of endemic plants in the montane forests and native shrublands. The native forest has decreased by approximately one-third. The area affected by Aristotelia chilensis increased from 6.5% to 14% of the total island area. Ugni molinae, once rare, is now abundant (4.6%), as is Acaena (11.9%). Rubus ulmifolius, not present 80 years ago, now covers about 7% of the island's surface. The distributions of all studied species except Rubus ulmifolius are significantly (p < 0.05) controlled by the environmental factors we examined. Inferring from potential distributions of Aristotelia chilensis and Ugni molinae, 50% of the native montane forest could be invaded or replaced (with a probability of >60%) by these plants. Based on the invasion speed of the past 80 years, this would take another 80 years if conservation measures do not succeed.