Exergy作为热力学指标是指系统从给定状态到与其周围介质达到热力学平衡所需做的最大功,Exergy概念被生态学家借鉴应用于生态系统的研究,使它有了生物学的含义。应用Exergy作为生态指标,用于指示崇西潮滩湿地生态工程中受到干扰的大型底栖动物群落结构的复杂的恢复过程。用BACI(before versus after,control versus impact)方法进行底栖动物采样,根据(a)不同食性类群的代码基因数;(b)储存在有机体基因内的信息;(c)种水平上的基因组尺度(C值)作为参数估算局域Exergy。结果显示工程区的Exergy值在工程干扰后9d时降到最低,接着工程区大型底栖动物群落的Exergy值逐渐与周围对照区趋向平衡。270d后,工程区的大型底栖动物群落得到恢复。3种不同方法估算的区域Exergy值表现出极为相似的动态趋势,进一步证实了用基因组尺度数据估算Exergy的可行性和优越性。研究表明Exergy指标不但适用于干扰后底栖动物群落恢复过程的监测,而且适合更广泛的生物系统研究。用周边对照区作为计算受干扰群落的局域Exergy值的动态参考比用历史资料更合适。
Benthic macroinvertebrate communities in Spartina alterniflora zones in the Yangtze Estuary, in China, were investigated seasonally in 2005, and their structure and biodiversity were analyzed. Twenty-one species were identified, across four Classes; 10 species of Crustacea, five species of Polychaeta, five species of Gastropoda, and one species of Lamellibranchia. Dominant species included： Assiminea sp., Notomastus latericeus, Cerithidea largillierl, Gtauconome chinensi and Gammaridae sp. Functional groups were comprised of a phytophagous group and a detritivorous group. The average density of all benthic macroinvertebrates was 650.5 ±719.2 inds/m^2 in the survey area. The high value of the standard deviation of the average density was a result of abundant Assiminea sp. at Beihu tidal flats. The average density of macroinvertebrates from Beihu tidal flat, Chongming Dongtan to Jinshanwei tidal flat decreased gradually. There was significant difference between compositions and abundance of macroinvertebrates along the estuary gradient （P 〈 0.05）. The density and biodiversity were highest in summer and lowest in winter. The mean biomass of macroinvertebrates was 20.8 ± 6.1 g/m^2. Biomass changed seasonally in the same way as density, with the change in biomass being： summer （Aug.） 〉autumn （Oct.） 〉spring （Apr.） 〉 winter （Dec.）. A BIO-ENV analysis showed that the mean grain size of sediment, height of Spartina and salinity were the ma- jor factors which affected the structure of the macroinvertebrate community. Variations in the community structure were probably caused by the population dynamics of S. alterniflora along with the variation in sampling time and location.
