Abstract
A new multimetric index (HeLLBI) based on littoral benthic macroinvertebrates is presented in this paper for classification of Greek natural lakes, in compliance with the requirements of Water Framework Directive (WFD). The method was developed based on the collection of littoral benthic invertebrate fauna and environmental data from 109 sampling sites in 21 natural lakes of the Greek National Water Monitoring Network. We focused the analysis on the effects of shore morphological alterations and eutrophication to the littoral invertebrate fauna, identified to family level, except oligochaetes, which were identified as a class, and more particularly to taxonomic composition and abundance, to taxa sensitivity, and to richness/diversity. Three metrics were included in the multimeric index: the relative abundance of Odonata classes, the Average Score per Taxon, and the Simpson’s diversity index. The metrics were converted to ecological quality ratios and ecological class boundaries were defined. The final multimetric index HeLLBI is expressed as an arithmetic average of normalized ecological quality ratios of the above metrics and a final score was assigned to each lake. Pressure-response relationships of HeLLBI scores were statistically tested for morphological alterations, expressed as percentage of artificial shoreline, and eutrophication, expressed as total phosphorus. The HeLLBI scores correspond to ecological classes, according to WFD, and sampling sites with different ecological status contained distinct biological communities; those at high status where more diverse and with sensitive taxa and as the water quality deteriorated, macroinvertebrate assemblages consisted of fewer and more tolerant to degradation taxa. The HeLLBI method gave a reliable assessment of littoral benthic invertebrate fauna of Greek natural lakes and could be a useful tool for the classification of ecological status of other Mediterranean lakes.
Highlights
Freshwater ecosystems host remarkable biodiversity; they cover less than 1% of Earth’s surface, they host approximately one-third of vertebrate species and 10% of all species (Strayer &1 3 Vol.:(0123456789) 745 Page 2 of 16Dudgeon, 2010)
Our results show that Hellenic Lake Littoral Benthic Macroinvertebrate assessment method (HeLLBI) is a fully WFDcompliant assessment method that classifies Greek lakes according to their ecological status, based on the effects of shoreline alteration and eutrophication on littoral macroinvertebrates
The Water Framework Directive (WFD)-compliant HeLLBI assessment method based on littoral benthic invertebrate fauna in Mediterranean lakes in Greece was developed from data of the Greek National Water Monitoring Network
Summary
Freshwater ecosystems host remarkable biodiversity; they cover less than 1% of Earth’s surface, they host approximately one-third of vertebrate species and 10% of all species (Strayer &1 3 Vol.:(0123456789) 745 Page 2 of 16Dudgeon, 2010). Responding to the need for protection of surface waters in Europe, in the context of river basin management planning, the Water Framework Directive (WFD) fostered the development of ecological assessment methods for different groups of organisms (i.e., phytoplankton, macrophytes and phytobenthos, macroinvertebrates, and fish) for aquatic ecosystems (lakes, rivers, transitional waters, and coastal waters) (European Commission, 2000). The assessment methods respond to the pressures exerted on these ecosystems and aim to classify ecological status at a five-level classification scheme, indicating the degree of deviation from reference conditions (European Commission, 2000). Still remain under pressure from a range of human activities; according to the European Environment Agency latest report (EEA, 2018), the main significant pressures on surface water bodies are hydromorphological pressures (40%), diffuse source pollution (38%), mainly coming from agriculture, and atmospheric deposition (38%), related to mercury, followed by point sources (18%) and water abstraction (7%). According to the same report, the main impacts on surface water bodies are nutrient enrichment, chemical pollution, and altered habitats due to morphological changes, e.g., shoreline alterations
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