Pillwort (Pilularia globulifera) - Species Action Plan

Ref 2/S21 Species Action Plan 21
Plan Author: Norfolk Wildlife Trust
Plan Co-ordinator: Waterbodies BAP Topic Group
Plan Leader Norfolk Wildlife Trust
Final March 2007

Action Plan Summary

Current Status

National Status

  • The plant is classified as Near Threatened (Cheffings and Farrell, 2005). This means that current trends are likely to cause its status to shift to Vulnerable in the near future. It is also internationally rare and declining within its western European range, to which it is endemic; as such, the UK holds a substantial proportion of the world population. In the UK in the past 100 years it has been recorded in 250 ten km squares, but only in 90 of these since 1970.
  • Pillwort receives general protection in England and Wales under the Wildlife and Countryside Act 1981.

Norfolk Status

  • In recent years, pillwort has been present at two sites: on the Norfolk side of the Lound ponds, which straddle the Norfolk/Suffolk county boundary; and at a small pond at Narrowgate Corner, Rollesby.
  • Pillwort remains on the Norfolk side of the Lound ponds (found at TG 50434 00557 in autumn 2006, M. Bradbury, pers. obs.), although its status along the Norfolk shoreline requires clarification. It may have been lost from the Rollesby site, following modifications to the pond and changes in site management in circa 2003.
  • Pillwort was recorded historically at a further 14 sites or localities in Norfolk (four sites during the 20th century/ten sites during the 19th century).

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Current factors causing loss or decline in Norfolk

  • Cessation of disturbance to habitat provided by grazing animals allowing competing vegetation to colonise bare ground.
  • Colonisation by invasive non-native species which have similar habitat requirements, particularly Crassula helmsii; this species is present and increasing at Lound ponds on the Norfolk/Suffolk county boundary.
  • Cessation of natural water level fluctuations through water level control.
  • Modifications to ponds including over-deepening, creation of steeply sloping banks, permanent flooding and change to fisheries use.
  • Site drainage.
  • Eutrophication of water bodies causing increases in pH and growth of competitive vegetation.

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Current Action in Norfolk

  • The Broads Authority and Essex & Suffolk Water are working in a partnership at Lound (on land owned by E&SW), through which a Catchment Officer is employed, to improve water quality and biodiversity. This is being achieved through direct site management and advice to local farmers.
  • Routine monitoring of pillwort and Crassula helmsii populations is undertaken by the Lound Catchment Officer.
  • Options appraisal addressing Crassula helmsii is carried out by the Catchment Officer. The extent and distribution of Crassula helmsii precludes its complete removal, so focussed removal is being trialled in pillwort 'hotspots'.
  • The Norfolk Biodiversity Partnership will work collaboratively with the Suffolk Biodiversity Partnership to achieve pillwort action plan objectives and targets where opportunities arise.

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Action Plan Objectives and Targets

National

  • Maintain current range of the species in the UK in 91 10-km squares.
  • Maintain extant viable populations in the seven vulnerable areas.
  • Establish two new metapopulations within the species' historic range (excluding the New Forest) by 2010.

Norfolk

  • Restore colonies along Norfolk shoreline at Lound ponds by 2010.
  • Re-establish an additional two colonies at suitable former sites and localities with favourable condition by 2012.

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