CRB: Collaborative Research: The Direct and Indirect Effects of Biological Invasions on Biodiversity in New England Kelp Beds

9700331科耶人类引进自然范围以外的物种正在迅速使地球生物群同质化，并对陆地、水生和海洋生物栖息地的生物多样性构成重大威胁。尽管生物入侵对生物多样性的潜在影响已经被认识到几十年了，但直到最近，大多数研究都集中在陆地或淡水上，而不是海洋栖息地。人为引入海洋物种的数量很多，并在一些当地人身上产生了戏剧性的影响。虽然在过去的15年里，人们已经了解了很多关于引进物种的知识，但关于海洋系统的概括是难以捉摸的。这项研究将探讨引进物种对西北大西洋海藻群落的影响。具体地说，这项研究将研究草食和竞争对引入的脆弱藻类和西北大西洋本地海藻群落的交互影响，苔藓虫对这些群落中海藻的间接影响，以及增加藻类和减少海藻生物量对以海藻为苗圃栖息地的鱼类和十足类动物的人口学的影响。新英格兰的海带群落在两个交替的状态之间转移：一个是以海带为主导的物种丰富的群落，另一个是以海胆和甲壳珊瑚藻类为主的物种贫乏的群落。最近，一个由引进的绿藻的单一养殖组成的新群落--Codium Fragile Tomentosoides--现在在该地区盛行。此外，苔藓虫的引入似乎也严重影响了海藻群落。利用一系列多因素实验和描述性研究，本研究将阐明群落结构变化的原因，从而解释这些海藻群落中人类造成生物多样性急剧丧失的机制。

9700331 Coyer Human introductions of species outside their natural range are rapidly homogenizing the earth's biota, and are a major threat to biodiversity in terrestrial, aquatic and marine habitats. Although the potential impact of biological invasions on biodiversity has been recognized for decades, until recently, most research has focused on terrestrial or freshwater rather than marine habitats. Anthropogenic introductions of marine species are numerous and have had a dramatic impact in some locals. While much has been learned about introduced species over the last 15 years, generalizations relative to marine systems are elusive. This study will address the effects of introduced species on kelp bed communities in the northwest Atlantic Ocean. Specifically, this research will examine the interactive effects of herbivory and competition on the introduced alga Codium fragile and the native kelp community of the northwest Atlantic, the indirect effects of a bryozoan on kelps in these communities, and the impact of increasing Codium and decreasing kelp biomass on the demography of fishes and decapods that use seaweed beds as nursery habitats. The kelp bed communities of New England shift between two alternate states: a species-rich community dominated by laminarian kelps, and a species-poor community dominated by sea urchins and crustose coralline algae. Recently, a new community consisting of a monoculture of the introduced green alga, Codium fragile tomentosoides, is now prevalent in the region. In addition the introduction of a bryozoan also appears to have severely impacted kelp bed communities. Using a series of multi-factor experiments and descriptive studies, this research will elucidate the causes of this shift in community structure, and therefore explain the mechanisms underlying the dramatic, human-induced loss of biodiversity in these kelp communities.