Understanding good ecological status : a palaeolimnological approach

The current study uses multiproxy palaeolimnological analysis of sediment cores to reconstruct the long-term (10² to 10³ years) nutrient status of Upper Talley and Llyn Pencarreg, two closely adjacent, moderately nutrient-enriched lakes in Carmarthenshire, South Wales. The use of diatoms, Pediastrum and ephippia allows for the analysis of changes in ecosystem dynamics in response to nutrient enrichment, whilst pollen, charcoal analysis and archaeology enables the degree to which limnological change was driven by human impact to be examined. Reconstruction of long-term ecosystem status shows that despite the similarity of environmental parameters, Upper Talley and Llyn Pencarreg are very different lakes. Upper Talley (max. depth; 4m) demonstrates constant fluctuations in ecosystem dynamics, typical of shallow lakes with a high sensitivity to environmental change, whilst Llyn Pencarreg (max. depth 1 Om) illustrates a high degree of stability with gradual changes in limnological status that are indicative of deeper lakes with fewer functional groups. Within the context of the EUWFD's aim to restore lakes to good ecological status, the results indicate the need for a more detailed methodology that accounts for the complexity of long-term ecosystem dynamics in response to human impact, examines changes at different levels of the food chain using a range of proxy indicators and locates realistic baseline states based on individual lake ecology of pre-impact conditions. In this respect the ultimate aim of restoring lakes to good ecological status in a range of lake types is more likely to be achieved.EThOS - Electronic Theses Online ServiceUniversity of HullGBUnited Kingdo