瑞英两国科学家近日研究发现，生物多样性的丧失给食物的生产、水质量以及二氧化碳的水平带来的影响要比之前人们估计的要严重的多。这一研究将有助于为今后环境政策的制定提供指导。相关论文发表在7月12日的《自然》杂志上。
进行该项研究的是瑞士苏黎世大学的AndyHector和英国牛津大学的RobertBagchi。他们通过一种新方法分析了来自欧洲草原的数据，结果发现，牵涉的生态过程越多，维持这些生态过程所需的物种也会相应增加。
这与以前的一些研究结果很不相同。Hector说：“之前的一些分析聚焦范围都很窄，从而得出结论认为，对一个生态系统重要的物种也能在其它所有方面起作用。而事实并不是这样。”
此次的研究首次证实，一个地方的不同生态系统过程会受到不同物种群的影响。英国谢菲尔德大学的OwenPetchey说：“人们过去经常谈到这些，但一直没有相关证据支持。这次的研究表明，对一个全能性生态系统来说，最大数量的物种必须得到保护。生物多样性是必须的，人类依赖生态系统提供很多东西。这一研究将在很大程度上影响政策的制定。”
1997年的一份评估报告认为，一个包括生物分解、土壤形成、营养和水分循环以及植物生长的生态系统过程每年可提供给人类的价值高达33万亿美元。而2005年的联合国报告指出，过去50年人类对生物多样性造成的损害比其它任何时期都要严重。所以，只有及时扼住恶化的趋势，人类才能继续享受这一大自然的馈赠。（科学网梅进/编译）
原始出处:
Letter
Nature 448, 188-190 (12 July 2007) | doi:10.1038/nature05947; Received 13 April 2007; Accepted 15 May 2007
Biodiversity and ecosystem multifunctionality
Andy Hector1 & Robert Bagchi1,2
Institute of Environmental Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
Present address: Department of Zoology, University of Oxford, Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK.
Correspondence to: Andy Hector1 Correspondence and requests for materials should be addressed to A.H. (Email: ahector@uwinst.uzh.ch).
Biodiversity loss can affect ecosystem functions and services1, 2, 3, 4. Individual ecosystem functions generally show a positive asymptotic relationship with increasing biodiversity, suggesting that some species are redundant5, 6, 7, 8. However, ecosystems are managed and conserved for multiple functions, which may require greater biodiversity. Here we present an analysis of published data from grassland biodiversity experiments9, 10, 11, and show that ecosystem multifunctionality does require greater numbers of species. We analysed each ecosystem function alone to identify species with desirable effects. We then calculated the number of species with positive effects for all possible combinations of functions. Our results show appreciable differences in the sets of species influencing different ecosystem functions, with average proportional overlap of about 0.2 to 0.5. Consequently, as more ecosystem processes were included in our analysis, more species were found to affect overall functioning. Specifically, for all of the analysed experiments, there was a positive saturating relationship between the number of ecosystem processes considered and the number of species influencing overall functioning. We conclude that because different species often influence different functions, studies focusing on individual processes in isolation will underestimate levels of biodiversity required to maintain multifunctional ecosystems.
