Highly humic lakes are typical for the boreal zone. These unique ecosystems are characterised as relatively undisturbed habitats with brown water, high acidity, low nutrient content and lack of macrophytes. Current lake assessment methods are not appropriate for ecological assessment of highly humic lakes because of their unique properties and differing human pressures acting on these ecosystems. This study proposes a new approach suitable for the ecological status assessment of highly humic lakes impacted by hydrological modifications. Altogether, 52 macroinvertebrate samples from 15 raised bog lakes were used to develop the method. The studied lakes are located in the raised bogs at the central and eastern parts of Latvia. Altered water level was found as the main threat to the humic lake habitats since no other pressures were established. A multimetric index based on macroinvertebrate abundance, littoral and profundal preferences, Coleoptera taxa richness and the Biological Monitoring Working Party (BMWP) Score is suggested as the most suitable tool to assess the ecological quality of the highly humic lakes.

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如何评估高腐殖质湖泊的生态状况？基于底栖无脊椎动物的新方法的开发

北部地区是典型的高度腐殖化的湖泊。这些独特的生态系统的特征是栖息地相对不受干扰，有棕色水，高酸度，低养分和缺乏大型植物。当前的湖泊评估方法由于其独特的特性以及作用于这些生态系统的不同人类压力而不适用于高度腐殖化湖泊的生态评估。这项研究提出了一种新方法，适用于受水文变化影响的高度腐殖湖的生态状况评估。总共使用了来自15个凸起沼泽湖的52个大型无脊椎动物样品来开发该方法。被研究的湖泊位于拉脱维亚中部和东部的凸起沼泽中。由于没有其他压力，水位的变化被认为是对腐殖质湖生境的主要威胁。