TITLE	The role of diversity and functional traits of species in community invasibility
AUTHOR	Kaiyang Xu South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, The People's Republic of China Wanhui Ye* South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, The People's Republic of China Honglin Cao South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, The People's Republic of China Xiong Deng South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, The People's Republic of China Qihe Yang South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, The People's Republic of China Yun Zhang South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, The People's Republic of China
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ABSTRACT	The invasion of exotic species into assemblages of native plants is a pervasive and widespread phenomenon. Many theoretical and observational studies suggest that diverse communities are more resistant to invasion by exotic species than less diverse ones. However, experimental results do not always support such a relationship. Therefore, the hypothesis of diversity-community invasibility is still a focus of controversy in the field of invasion ecology. In this study, we established and manipulated communities with different species diversity and different species functional groups (16 species belong to C3, C4, forbs and legumes, respectively) to test Elton's hypothesis and other relevant hypotheses by studying the process of invasion. Alligator weed (Alternanthera philoxeroides) was chosen as the invader. We found that the correlation between the decrement of extractable soil nitrogen and biomass of alligator weed was not significant, and that species diversity, independent of functional groups diversity, did not show a significant correlation with invasibility. However, the communities with higher functional groups diversity significantly reduced the biomass of alligator weed by decreasing its resource opportunity. Functional traits of species also influenced the success of the invasion. Alternanthera sessilis, in the same morphological and functional group as alligator weed, was significantly resistant to alligator weed invasion. Because community invasibility is influenced by many factors and interactions among them, the pattern and mechanisms of community invasibility are likely to be far subtler than we found in this study. More careful manipulated experiments coupled with theoretical modeling studies are essential steps to a more profound understanding of community invasibility.
KEYWORD	Alligator weed; Community; Diversity; Functional groups; Invasibility; Invasion;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 45 Number 2 April 2004, page 149-157, 9 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China