Tassel Stonewort (Tolypella intricata) - Species Action Plan

Ref 2/S6 Species Action Plan 6
Plan Author: KLCIDB
Plan Co-ordinator: Waterbodies Topic Group
Plan Leader RSPB
Final draft January 2007

Current Status

National Status

  • This species has been found at seven British sites since 1970: ponds in Inglestone Common, Gloucestershire (seven colonies); one site in Cambridgeshire (four colonies); two sites in Norfolk; and one site each in Suffolk, Somerset and Worcestershire. The species reappeared at the Somerset site following ditch clearance in 1989, but has not been seen since. It was once more widespread, being recorded from 42 localities pre-1970, most of which were in southern and eastern England, but it also extended as far north as Durham. It is scattered throughout Europe, extending to southern Scandinavia, the Black Sea and North Africa, but is rare in the Mediterranean region.
  • In Britain, this species is classified as Endangered. It receives general protection under the Wildlife and Countryside Act 1981.

Norfolk Status

  • There are only two recent records from Norfolk:
    • Cantley Marshes (TG 368 042), in 1996. The species has not been found in subsequent, brief searches. However, the grazing and ditch management regimes are considered favourable for this species, so it is likely to still be present.
    • Sculthorpe Fen (TF 90466 30180 / TF 90470 30240), in 2006. The presence of T. intricata at this site was recently discovered by Geoff Nobes.
  • Historically, the species was recorded at Gillingham Marshes (c.TM 41 91) in 1950, but its current status at this site is unknown (Stewart 2002).

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Current factors causing loss or decline in Norfolk

  • Lack of disturbance (often due to the decline of traditional management practices such as ditch maintenance and grazing), leading to displacement of this species by more competitive vegetation.
  • Falling water table levels may have been responsible for the loss of populations at several sites and may still be a threat at some extant sites. The extent of this problem needs further investigation.
  • Eutrophication.

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Current Action in Norfolk

  • The site at Sculthorpe Fen forms part of the Sculthorpe Moor Community Nature Reserve and is also a County Wildlife Site. It is managed for nature conservation by the Hawk & Owl Trust, under a lease agreement with the landowner.
  • Cantley Marshes are managed by the RSPB under a management plan agreed with Natural England and under an ESA agreement, ensuring suitable cattle grazing and ditch management will continue.
  • Regular surveys and occasional searches specifically for this species have taken place at Cantley Marshes.
  • A PhD is currently being carried out by Stephen Lambert (University of East Anglia) into the survival parameters of UK BAP stoneworts, including T. intricata.

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Action Plan Objectives and Targets


The following targets are the current targets following the 2006 targets review:

  • Maintain two extant metapopulations of this species.
  • Increase population from two to three metapopulations by 2010.
  • Maintain viable populations at five extant sites outside existing metapopulations.


  • Maintain viable populations at the two extant sites (Sculthorpe Fen and Cantley Marshes).
  • Survey, assess feasibility and if appropriate, reintroduce to Gillingham Marshes.

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