Goldsmith, B; Salgado, J; Bennion, H; McGowan, S; Hoare, D; Yang, H; (2013) Using novel palaeolimnological techniques to define conservation objectives for Hatch Mere: Report for Cheshire Wildlife Trust. (ECRC Research Report 158 ). ENSIS, UCL Environmental Change Research Centre: London, UK.

Preview

Text CWT Hatch Mere 2013 Final_Report.pdf - Accepted Version Download (2MB) | Preview

Abstract

This is the final report to Natural England on the project ‘Using novel palaeolimnological techniques to define lake conservation objectives for Hatch Mere’. The aim is to use existing and recently developed palaeoecological techniques to define reference conditions and assess the condition of Hatch Mere Special Scientific Interest (SSSIs) in the Cheshire meres, and thereby assist in the setting of conservation objectives and management goals. Two sediment cores (one open water and one marginal), approximately 1 m in length, were collected from Hatch Mere in August 2011. The cores were sampled at 1 cm intervals throughout and approximately ten samples from each site were analysed for diatoms, Cladocera, macrofossils, geochemistry (XRF) and pigments. The cores were dated using radiometric techniques in order to place the fossil remains within a known time frame. An existing diatom-total phosphorus (TP) transfer function was applied to the diatom data to reconstruct the nutrient history of the mere. The dating results suggest that the open water core (HAT3) extends back to ~1800 AD and the marginal core extends back beyond ~17o00 AD. The palaeoecological data indicate that the site has been a moderately enriched lake for the whole of the period represented by the cores with diatom-inferred TP concentrations of ~30 μg L-1 in the lower part of the record. However, there were marked changes across a range of indicators from the early 1800s indicative of enrichment, which has continued through the twentieth century. The key changes were the expansion of the eutrophic diatom species Cyclostephanos dubius and hence an increase in diatom-inferred TP to ~84 μg L-1, a steady increase in pigment concentrations from all algal groups, and shifts in the zooplankton community indicative of increased pelagic productivity. Eutrophication has resulted in marked changes in the aquatic plant community from a structurally diverse flora with abundant Charophytes, nymphaeids and taxa with a mix of seasonalities to the current state with no submerged flora and only Nuphar lutea. The most notable changes in the macrofossil record have occurred from the mid-1800s and are, therefore, coincident with the main phase of enrichment. The dominance of the upper sediments by planktonic zooplankton and abundant Daphnia ephippia towards the top of the core, lends further weight to a plankton dominated system. This study provides information on the plant and animal communities that were present in the lake prior to the major eutrophication phase and this significantly alters the generic target previously set for the lake and will be valuable for setting targets for future management of the site.

Download activity - last month

Export as JSONCSVXML

Download activity - last 12 months

Export as JSONXMLCSV

Downloads by country - last 12 months

Export as XMLCSVJSON

Archive Staff Only

View Item