海岸带生态系统健康评价中能质和生物多样性的差异——以江苏海岸带为例

生态系统健康评价是生态系统保护和监测研究的重要内容,该过程迫切需要综合性强、准确性高的指标,能质和生物多样性指标都是生态系统健康评估中的有效指标.以江苏省海岸带游泳和底栖生物群落为对象,沿海岸线从海州湾到长江入海口北岸选取15个站点,调查研究江苏省海岸带生态系统能质和生物多样性及其空间分布格局.结果表明:江苏海岸带除了中部地区能质和结构能质值较一致(都偏小)外,南北差异明显,生物多样性指数空间分布情况为南部Margalef指数略大于北部,中部较小,Shannon Wiener和Simpson指数空间分布都为南部＞中部＞北部；能质与生物多样性指标在高级生态系统中反映的生态系统健康状态一致,在中低级生态系统中差异明显；能质与生物多样性指标关联程度低,前者的测算侧重于生态系统中物种的等级,后者的测算侧重于物种的数量；总结能质和生物多样性指标在理论支撑、建立理论视角、与生态系统健康对应关系、应用模型以及局限性等方面的差异,研究结果在一定程度上可以丰富和完善生态系统健康评价研究理论与方法体系.

The difference between exergy and biodiversity in ecosystem health assessment: a case study of Jiangsu coastal zone

Ecosystem health assessment is a fundamental issue in ecosystem protection and monitoring studies. Maintaining a healthy ecosystem is regarded as the key management objective for more and more environmental sectors. Therefore, a comprehensive and accurate index to indicate the ecosystem status is urgently needed. In previous researches, both exergy and biodiversity indicators are effectively and commonly used in assessing ecosystem health. But the difference between them is not reported. This paper provides a case study in Jiangsu coastal zone. Starting from Xiuzhen estuary in north and stretching down to the north shore of Yangtze estuary in south, Jiangsu coastal zone lasts for 954km. This research focuses on the nektonic and benthic communities in three different geographical areas (the Haizhou Bay-in the north, radiative sand ridges-in the middle, and the north shore of Yangtze estuary-in the south). 15 samples were collected in the marine survey conducted during July-Aug. 2006. After analyzing the exergy and bio-diversity values at these 15 locations, the spatial distribution structure of exergy and bio-diversity values were revealed. Further analysis was conducted based on Arcgis and SPSS software. Following results are obtained: Both exergy and structure exergy values in radiative sand ridges area are consistent. They are smaller than those in Haizhou Bay and Yangtze estuary region. In Haizhou Bay, the exergy value is lower than that in Yangtze estuary region, while the structure exergy values distribute oppositely. As one kind of biodiversity index, Margalef index value in south area is slightly larger than that in the north, while the value in the middle is the least. The distribution patterns of both Shannon Wiener and Simpson index values are south > middle > north. In mature ecosystem, both exergy and biodiversity can indicate the similar health status. But when they are used in valuing less mature ecosystems, significant difference occurs. This is because exergy measures ecosystem from cells'' level, while biodiversity more focuses at species level. Further analysis also indicates that 15 samples can be divided into four categories: site 14 is healthy, 8, 11, 12 are sub-healthy, 1, 6, 7, 10, 13 are poor, others are uncertainty. The differences between exergy and the biodiversity indicators can be concluded as follows: (1) The theoratical base of exergy is thermodynamics, from which ecosystem''s organism structure and genetic information can be reflected in relatively microcosmic perspective, while biodiversity indicators are based on population size and species abundance, which illustrate the stability of ecosystem in macro perspective. (2) Exergy can directly reflect the status and the changes of ecosystem, while biodiversity indicators indicate the ecological health status in an indirect way. (3) Exergy and structure exergy are complementary, while biodiversity indicators are parallel. (4) Exergy calculation is more or less restricted by gene measurement techniques, while, the ecological changes in diversity cannot be distinguished whether from species distribution or the quantity change of species.