Mostafavi Hossein, Schinegger Rafaela, Melcher Andreas, Moder Karl, Mielach Carina, Schmutz Stefan
Department of Water, Atmosphere and Environment, Institute of Hydrobiology and Aquatic Ecosystem Management, BOKU University of Natural Resources and Life Sciences, Vienna, Austria ; Department of Bio-diversity and Ecosystem Management, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran.
Department of Water, Atmosphere and Environment, Institute of Hydrobiology and Aquatic Ecosystem Management, BOKU University of Natural Resources and Life Sciences, Vienna, Austria.
Limnologica. 2015 Mar;51:37-52. doi: 10.1016/j.limno.2014.10.006.
A major issue for water resource management is the assessment of environmental degradation of lotic ecosystems. The overall aim of this study is to develop a multi-metric fish index for the cyprinid streams of the Caspian Sea Basin (MMICS) in Iran. As species diversity and composition as well as population structure in the studied streams are different to other regions, there is a substantial need to develop a new fish index. We sampled fish and environmental data of 102 sites in medium sized streams. We analysed human pressures at different spatial scales and determined applicable fish metrics showing a response to human pressures. In total, five structural and functional types of metrics (i.e. biodiversity, habitat, reproduction, trophic level and water quality sensitivity) were considered. In addition, we used 29 criteria describing major anthropogenic human pressures at sampling sites and generated a regional pressure index (RPI) that accounted for potential effects of multiple human pressures. For the MMICS development, we first defined reference sites (least disturbed) and secondly quantified differences of fish metrics between reference and impaired sites. We used a Generalised Linear Model (GLM) to describe metric responses to natural environmental differences in least disturbed conditions. By including impaired sites, the residual distributions of these models described the response range of each metric to human pressures, independently of natural environmental influence. Finally, seven fish metrics showed the best ability to discriminate between impaired and reference sites. The multi-metric fish index performed well in discriminating human pressure classes, giving a significant negative linear response to a gradient of the RPI. These methods can be used for further development of a standardised monitoring tool to assess the ecological status and trends in biological condition for streams of the whole country, considering its complex and diverse geology and climate.
水资源管理的一个主要问题是对流水生态系统环境退化的评估。本研究的总体目标是为伊朗里海盆地的鲤科溪流开发一种多指标鱼类指数（MMICS）。由于所研究溪流中的物种多样性、组成以及种群结构与其他地区不同，因此迫切需要开发一种新的鱼类指数。我们在中型溪流中的102个地点采集了鱼类和环境数据。我们分析了不同空间尺度上的人类压力，并确定了对人类压力有响应的适用鱼类指标。总共考虑了五种结构和功能类型的指标（即生物多样性、栖息地、繁殖、营养级和水质敏感性）。此外，我们使用了29条描述采样点主要人为压力的标准，并生成了一个区域压力指数（RPI），该指数考虑了多种人类压力的潜在影响。为了开发MMICS，我们首先定义了参考地点（受干扰最小），其次量化了参考地点和受损地点之间鱼类指标的差异。我们使用广义线性模型（GLM）来描述在受干扰最小的条件下指标对自然环境差异的响应。通过纳入受损地点，这些模型的残差分布描述了每个指标对人类压力的响应范围，而不受自然环境影响。最后，七个鱼类指标表现出区分受损地点和参考地点的最佳能力。多指标鱼类指数在区分人类压力等级方面表现良好，对RPI梯度给出了显著的负线性响应。考虑到该国复杂多样的地质和气候，这些方法可用于进一步开发标准化监测工具，以评估全国溪流的生态状况和生物状况趋势。
