Spatial and temporal variations of benthic macroinvertebrate communities in lake Kastoria, Nothern Greece

Abstract

Lake Kastoria, in northwestern Greece, is a shallow urban natural lake. The objectives of this study were a) to investigate spatial and temporal variations of benthic macroinvertebrate communities in Lake Kastoria and b) to assess the lake water quality with the use of a WFD-compliant national method. Samplings were undertaken at the littoral zone of the lake at 5 selected sites during spring 2017 and 2021, according to the Hellenic Lake Littoral Benthos (HeLLBI) assessment method. Non-metric multidimensional (NMDS) scaling and one-way analysis of similarity percentages were applied to visualize similarities and to identify the taxa responsible for the discrimination in benthic macroinvertebrate communities between different sampling periods, among sites and water quality classes. In total, 5569 individuals were collected and 37 taxa groups were identified. NMDS plot provided a useful display of the actual multivariate distance among samples (stress value: 0.14). Benthic invertebrate communities showed considerable spatial variation at local scale (sampling site level) except for one site but no clear temporal variation. The mean EQR value of HeLLBI showed moderate water quality of the lake. All sites showed no change in their water quality across time except for 2 sites that improved (poor to moderate and good respectively). Benthic macroinvertebrates communities at good water quality sites differed in composition and showed higher biodiversity compared to those at moderate and poor sites. Management measures should be site-adapted in Lake Kastoria and priority could be given to the conservation and restoration of the littoral zone.