PARENT SESSION

2N - Field Studies
Poster Hall
8:30 AM - Monday, 28 April 2003
Chair: Liess, M.¹, ¹
Co-chair: Berghahn, R.², ²

(MOP/121) The development of a baseline classification of microcrustacean assemblages of small waterbodies in Britain.

Yarwood-Buchanan, Sarah¹, Biggs, Jeremy ², Miller, Anne¹, Maund, Steve³, ¹ BMS, Oxford Brookes University, Gipsy Lane, Headington, Oxford, Oxon, UK² The Ponds Conservation Trust: Policy and Research, BMS, Oxford Brookes University, Gipsy Lane, Headington, Oxford, Oxon, UK³ Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire, UK

ABSTRACT- Microcrustaceans are important biotic components of aquatic ecosystems. While widely studied in larger waterbodies (lakes, reservoirs), little is known about their patterns of occurrence in permanent or temporary ponds. From a conservation perspective, these are important biodiversity components in the landscape. However, in the absence of information about their distribution, it is difficult to develop recommendations on approaches for managing ponds to support diverse zooplankton assemblages and encourage rare species. It also has important implications for aquatic risk assessment of pesticides. Higher-tier aquatic risk assessments in the EU are increasingly using pond micro- or mesocosms to assess the potential effects of pesticides at the population and community level. Whilst experimental methodologies for such studies are generally quite well-developed, there has been considerable debate concerning the extent to which the assemblages of various micro- and mesocosm designs are representative of those found in natural waters. Clearly, basic information on the distribution and ecology of organisms in natural waters is required to progress both the conservation and risk assessment practices. In order to address this lack of data in the UK, a survey has been carried out to develop the first baseline classification for crustacean zooplankton assemblages in small, lentic waterbodies across the UK. The presentation will discuss the findings in terms of the distribution and ecology of zooplankton found in a number of natural ponds in lowland Britain and compare these with microcrustacean assemblages in test mesocosms. assemblages of mesocosms.

Key words: Microcrustaceans, Mesocosms