D'Amelio S, Gerasi L
Istituto di Parassitologia, Università La Sapienza, Roma, Italy.
Parassitologia. 1997 Sep;39(3):237-41.
The degree of biological diversity is often used as an indicator of the well-being of ecological systems. This approach can also be applied to analyse biodiversity in parasite communities. In particular, studies on parasite communities can be employed to detect a decline in biodiversity which characterizes habitats affected by pollution. Beside the most widely used diversity indices, such as the Shannon, Brillouin and inverse Simpson, that have been widely applied in different host-parasite systems, new approaches have been recently developed in order to overcome problems related to high dominance. Walther et al. (1995) proposed an asymptotic equation suitable for evaluating parasite species richness as a function of sampling effort. Such an equation was earlier proposed by Miller and Weigert (1989) to describe plant species diversity and to calculate true species richness as the ratio between the increase in species richness (a) and the parameter that set the species richness asymptote (b). True species richness has been shown to decline in parasite communities of mugilids collected in polluted areas. Biodiversity calculations can also be run in parallel with other biological studies for the description of environmental conditions. The completion of parasite life cycles requires complex biocoenotic interactions and is restricted by environmental constraints. Therefore another approach for monitoring the health of an ecosystem was by analysing the ratio between monoxenous and heteroxenous parasite species infecting model hosts. By this methodology it was possible to confirm pollution effect highlighted by other quantitative methods.
生物多样性程度常被用作生态系统健康状况的指标。这种方法也可用于分析寄生虫群落的生物多样性。特别是，关于寄生虫群落的研究可用于检测生物多样性的下降，这是受污染影响栖息地的特征。除了在不同宿主 - 寄生虫系统中广泛应用的最常用的多样性指数，如香农指数、布里渊指数和反辛普森指数外，最近还开发了新的方法来克服与高优势度相关的问题。瓦尔瑟等人（1995年）提出了一个渐近方程，适用于评估寄生虫物种丰富度作为采样努力的函数。这样的方程早些时候由米勒和魏格特（1989年）提出，用于描述植物物种多样性，并将真实物种丰富度计算为物种丰富度增加量（a）与设定物种丰富度渐近线的参数（b）之间的比率。在污染地区采集的鲻科鱼类寄生虫群落中，真实物种丰富度已被证明有所下降。生物多样性计算也可以与其他生物学研究并行进行，以描述环境条件。寄生虫生命周期的完成需要复杂的生物群落相互作用，并受到环境限制。因此，监测生态系统健康的另一种方法是分析感染模型宿主的单宿主和多宿主寄生虫物种之间的比率。通过这种方法，可以确认其他定量方法所突出的污染效应。
