CRB: Direct and Indirect Effects of Key Alien Species in Two Hawaiian Forest Communities

9610413劳伦斯保护和恢复生物学中的一个关键问题是外来入侵物种的作用。尽管发展入侵生态学作为一门预测科学的价值越来越被认识到，但除非更频繁地使用操控实验，否则这可能是困难的。在这项拟议的研究中，操纵性实验将被用来分析夏威夷岛上一个干燥的森林地点的入侵物种的影响，那里的社区长期以来一直以其易受干扰的特征而闻名。这项研究的目标是确定夏威夷本土社区如何随着外来物种的消失而变化。具体地说，实验将确定当地物种在受干扰和受保护的栖息地的再生潜力。据推测，关键外来物种对这些森林中本地物种的分布和丰富度有不成比例的影响。实验地点将设在夏威夷岛上的考普莱胡保护区，在那里，促进火灾的外星人喷泉草现在很普遍。在清除喷泉草和控制老鼠之后，将监测本地和外来物种的招募情况。清除喷泉草和控制老鼠预计将导致对本地树冠、灌木和草本物种的补充增加。还将调查次要影响，如被喷泉草抑制的其他外来物种的入侵，以及随着本地物种数量的增加，对本地物种的食草性增加。夏威夷物种的高度特有和濒危并不是拟议研究的理由；更普遍的意义是加深对外来物种在破坏本地植物群落中的作用以及原生和次生影响的重要性的理解。夏威夷植物群落显然极易受到外星人入侵，这应该使人们更容易看到外来物种灭绝的后果。夏威夷群岛关于外来物种作用的经验教训应广泛适用于其他植物群落。

9610413 Lorence A key issue in conservation and restoration biology is the role of invasive, alien species. Although the value of developing invasion ecology as a predictive science is increasingly recognized, this may be difficult unless manipulative experiments are used more frequently. In the proposed research, manipulative experiments will be used to analyze the effects of invasive species in a dry forest site on the Island of Hawaii where communities have long been noted for their disturbance prone features. The goal of the research is to determine how native Hawaiian communities change in response to the removal of alien species. Specifically, experiments will determine the regeneration potential of native species in disturbed and protected habitats. It is presumed that key alien species have a disproportionate effect on the distribution and abundance of native species in these forests. The experimental site will be located in the Kaupulehu Preserve on the island of Hawaii in an area where the alien, fire promoting fountain grass is now widespread. Recruitment of native and alien species following removal of fountain grass and control of rats will be monitored. Removal of fountain grass and control of rats is expected to result in an increase in recruitment of the native canopy, shrub, and herbaceous species. Secondary effects will also be investigated such as the invasion of other alien species suppressed by fountain grass, and increased levels of herbivory on native species as they increase in abundance. The extraordinarily high degree of endemism and endangerment of Hawaiian species is not justification for the proposed research; of more general significance is an increased understanding of the role of alien species in disruption of native plant communities, and the significance of primary and secondary effects. The apparent extreme susceptibility of Hawaiian plant communities to invasion by aliens should make it easier to see the consequences of removal of alien species. Lessons learned in the Hawaiian Islands about the role of alien species should have broad applicability to other plant communities.