Using Coleoptera and Odonata as a monitoring tool for improving protected lake habitat characterisation: a case study from Ireland

Abstract

Abstract “Oligotrophic waters containing very few minerals of sandy plains” (habitat code 3110) and “Natural dystrophic lakes and ponds” (habitat code 3160) are two protected lake habitats under Annex I of the European Union Habitats Directive. Despite this level of protection, their conservation condition is considered unfavourable in most European biogeographic regions. The available classifications rely heavily on water chemistry and phytosociology while leaving other biological taxa under described. This study tested the use of Coleoptera and Odonata communities as a monitoring tool to characterise and distinguish both lake habitat types. Samples were collected from 24 sites in western Ireland over two seasons (spring and summer) using standard sweep netting methods. Despite a considerable level of overlap in assemblages found, communities were shaped by lake habitat type, sampling region and season. Overall, lake habitat 3110 hosted a higher diversity of taxa in summer dominated by dragonflies associated with larger, warmer waters, while lake habitat 3160 reflected higher Coleoptera diversity in spring typical of small, turbid, stagnant waterbodies. This research highlights the potential use of aquatic invertebrates as an important monitoring tool for these protected lake habitats. Findings of this work deepen current knowledge about these habitats and fill gaps in their classification, hence improving conservation condition assessment methods for Member States when reporting under the Habitats Directive.