Establishing realistic restoration targets for nutrient-enriched shallow lakes: linking diatom ecology and palaeoecology at the Attenborough Ponds, U.K.

摘要: Eutrophication is a major problem for shallow lakes in the U.K. lowlands. Over last few decades issues relating to management and restoration of these have come fore, including need develop methods establishing realistic targets. One group which key concern are Attenborough Ponds English Midlands, an interconnected series shallow, nutrient-enriched gravel-pit lakes. In November 1972, highly polluted River Erewash was diverted into Ponds. To determine ecological effects this event establish goals lake system, two complimentary studies were undertaken here; (i) monitoring ecology sedimentary representation diatom communities disturbed connected R. (Tween Pond: high nutrient concentrations, no submerged macrophytes) relatively undisturbed isolated from (Clifton lower abundant macrophytes), and; (ii) examination record short sediment core collected chosen Pond). The species composition, seasonality, relative productivity planktonic periphytic very different Tween Clifton Pond phases production/sedimentation observed during March–May July–September. By contrast, diatoms restricted single spring peak after May there switch dominance associated with development macrophytes. 1972 diversion clearly reflected Pond, by; abrupt shift dominance, increasing percentages late summer–autumn species. These changes suggest both significant enrichment macrophyte phytoplankton dominance. Numerical matching pre-1972 assemblages surface gravel-pits using Principal Components Analysis (PCA) squared chord distance measure revealed close analogues. Nevertheless, similarities between; habitat seasonality groups, contemporary survey data suggested that probably good pre-diversion analogue structure (e.g. biomass, composition architecture) phenology seasonality) practical value combining space-for-time substitution palaeoecological approaches discussed.