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

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

Integrated classification and assessment of lakes in Wales: Phase II

This report presents preliminary data from the second phase of the study on integrated classification and assessment of lakes in Wales. The classification and assessment project is described in detail by Allott et al. (1994). Ten lakes, listed on the following page are in the process of assessment. The report includes data on water chemistry and physical variables, aquatic macrophyte distribution maps, and species lists of aquatic macrophytes, epilithlic diatoms, open water zooplankton and littoral macroinvertebrates. Methodologies follow those given by Allott et al. (1994). A second report in July 1995 will incorporate further site specific information, including full site descriptions, sampling site information, and additional chemistry, littoral cladoceran and surface sediment diatom data. Further development of classification techniques will require a minimum of thirty lake integrated data sets

Multi-proxy studies in palaeolimnology

Multi-proxy studies are becoming increasingly common in palaeolimnology. Eight basic requirements and challenges for a multi-proxy study are outlined in this essay – definition of research questions, leadership, site selection and coring, data storage, chronology, presentation of results, numerical tools, and data interpretation. The nature of proxy data is discussed in terms of physical proxies and biotic proxies. Loss-on-ignition changes and the use of transfer functions are reviewed as examples of problems in the interpretation of data from multi-proxy studies. The importance of pollen analysis and plant macrofossil analysis in multi-proxy studies is emphasised as lake history cannot be interpreted without knowledge of catchment history. Future directions are outlined about how multi-proxy studies can contribute to understanding biotic responses to environmental change