Abstract

The Water Framework Directive 2000/60/EC (WFD) requires Member States of the European Union (EU) to use a pool of bioindicators, that is, Biological Quality Elements (BQEs), including fish species and each Member State shall, in fact, certify the compliance with the ecological quality goals of the WFD. The New Italian Index of the Ecological State of Fish Communities (NISECI) is the WFD-compliant index for the analysis of the fish species BQE in Italian river water bodies, both wadable and non-wadable, that are not (using WFD definitions) heavily modified or artificial. The WFD requires each index to relate the conditions found in the field to reference conditions corresponding to the absence of anthropogenic alterations or to minor anthropogenic alterations. The present study defines the logical basis on the model of refinement for the reference conditions of the metrics and submetrics of NISECI relating to the biological condition of indigenous and non-indigenous species. The model was tested on an empirical basis using data from 284 ichthyological samplings taken from river basins throughout Italy. In order to clean random errors and stochastic noise due to possible different sampling methods, the data was only collected using protocols that guarantee adequately homogeneous and reliable data of abundance (overall and by size). The developed approach provided comparable and homogeneous results throughout Italian watersheds; this allowed a standardized and robust refinement of the threshold values of the demographic parameters of NISECI. The procedure used, consistent with the spatially based reference condition and expert judgement reference condition approaches envisaged by the WFD, improves the analytical performance of the NISECI by increasing its power of resolution and is applicable in every Italian zoogeographic and ecological context.

摘要

水框架指令 2000/60/EC (WFD) 要求欧盟 (EU) 成员国使用生物指标库，即生物质量要素 (BQE)，包括鱼类物种，并且每个成员国实际上应，证明符合 WFD 的生态质量目标。新的意大利鱼类群落生态状况指数 (NISECI) 是符合 WFD 标准的指数，用于分析意大利河流水体中的鱼类物种 BQE，包括可涉水和不可涉水，这些鱼类（使用 WFD 定义）不是很严重修改或人工。WFD 要求每个指数将现场发现的条件与对应于不存在人为改变或轻微人为改变的参考条件相关联。本研究为 NISECI 与本地和非本地物种的生物条件相关的度量和子度量的参考条件的细化模型定义了逻辑基础。该模型使用来自意大利全境河流流域的 284 个鱼类学样本的数据在经验基础上进行了测试。为了清除由于可能的不同采样方法造成的随机误差和随机噪声，仅使用保证足够均匀和可靠的丰度数据（总体和按大小）的协议收集数据。开发的方法在整个意大利流域提供了可比较和同质的结果；这允许对 NISECI 人口参数的阈值进行标准化和稳健的细化。使用的程序，