The past, present and future of Llangorse Lake—a shallow nutrient-rich lake in the Brecon Beacons National Park, Wales, UK

Abstract

1. This paper provides an introduction to the ecology and conservation status of Llangorse Lake, a shallow nutrient-rich lake in the Brecon Beacons National Park, Wales, UK. The lake has been designated as a Site of Special Scientific Interest in Britain and was recently proposed as an internationally important conservation site under European Community legislation.2. The water chemistry and biota are indicative of alkaline, nutrient-rich conditions. Water transparency is low and there is evidence of deoxygenation above the surface sediments.3. The epilithic diatom flora exhibits the most diverse assemblage of taxa. Cocconeis placentula and Achnanthes minutissima dominate the epiphytic diatom flora, whilst the surface sediment diatom assemblage is largely composed of planktonic taxa.4. Phragmites australis and Typha latifolia are the dominant components of the emergent stands of marginal vegetation, which is flanked on the open water side by floating-leaved plant communities. Several species of Potmogeton are recorded as parr of the diverse submerged flora.5. The open water and littoral zooplankton assemblages are composed of a small number of cladoceran and copepod species. In contrast, a diverse assemblage of macroinvertebrates with large numbers of individuals is recorded. Oligochaetes are the most numerous group but the Mollusca, Hirudinea, Malacostraca and insects are also well represented.6. Artificial enrichment, power boating and fishery management are highlighted as key considerations for the future conservation of the lake. A number of non-indigenous plant and animal species are reported.7. The organizations that can play a role in the future management of the lake are identified and a number of management planning initiatives are discussed. Copyright (C) 1999 John Wiley & Sons, Ltd.