Eutrophic Standing Waters

Habitat Description

Eutrophic standing waters are highly productive because plant nutrients are plentiful, either naturally or as a result of artificial enrichment.

   

In their natural state eutrophic waters have high biodiversity; planktonic algae and zooplankton are abundant in the water column, submerged vegetation is diverse and numerous species of invertebrate and fish are present, in turn supporting a diverse breeding and wintering bird assemblage and other species like otters.

To prevent overlap with the Pond Action Plan, Eutrophic Standing Waters should be considered as areas of open, standing water over 2 hectares in size.

Current UK Status and Trends

No accurate estimate exists for the total area of this habitat in Britain, but there may be around 54,000 hectares in England. Overall trends are not clear but new eutrophic standing waters have been created in many areas through quarrying in floodplains.

Estimated Current Northants Resource

There are at least 1700 hectares of standing open water in Northamptonshire ranging from small ponds to large reservoirs. The proportion of this classed as eutrophic is unknown but will be significant.

Progress Towards BAP Targets 2002-2007

Most of the Nene Valley's open water bodies now receive full protection as a SSSI and as a proposed Special Protection Area and Ramsar site.

Main Issues and Threats

  • Diffuse pollution from agricultural and urban run-off, causing nutrient enrichment.
  • Over-stocking with coarse fish.
  • Disturbance and habitat degradation from water-based recreation and inappropriate shoreline development.
  • Impacts on native wildlife of alien species introduced accidentally or intentionally, e.g. signal crayfish, zander, Japanese knotweed, mink.

General Strategy

  • There is no urgent need for large new open water bodies to be created.
  • The existing resource needs to be managed carefully to reconcile demand for recreation and leisure opportunities with wildlife value of many lakes. Open water habitats play a key role in managing landscape quality and delivering Green Infrastructure opportunities.
  • The impacts of introduced species need to be monitored carefully and mitigation measures incorporated into site management plans if necessary. Management of some introduced species will require a coordinated catchment-wide strategy to be effective.
  • The effects of diffuse pollution on eutrophic standing waters in the County should be kept under review. Agri-environment schemes and the planning system should be used as appropriate to control and where possible reduce diffuse pollution problems.

Lead Partner

RSPB

Associated National Priority Species 

  • Clustered earth-moss
  • Common toad
  • Eurasian curlew
  • Grass-wrack pondweed
  • Herring gull
  • Otter (see species action plan.)
  • Water vole (see species action plan.)
Specific Management Required for Associated Species

Species

Northamptonshire Status

Management Prescriptions

Key Sites

Grass-wrack pondweed

Local

Retain wet ditches and canals, prevent eutrophication, monitor effects of boat traffic and associated pollution.

River Nene, Grand Union Canal

Targets

Target Code

Target Type

Target Description

Target Units

Northants Baseline Resource

Target

By

Unit Cost £

Total Cost £

NOR_ESW_T1

Achieving Condition

Maintain the condition of all eutrophic standing waters of known conservation importance currently judged in good condition.

Hectares

Unknown

No Loss

2015

Unknown

Actions

Action Code

Action Description

Lead Partner

Support Partner(s)

Related Target

NOR_ESW_SU_A1

Identify all eutrophic standing waters of >1ha in the Nene Valley target area and provide maintenance and enhancement advice to landowners, by 2012.

NBRC, NBP

NOR_ESW_T1

NOR_ESW_CA_A2

Produce guidelines for developers and local authorities (including RNRP) on monitoring standards, mitigation, development 'zones' and the process of Appropriate Assessment for proposals affecting lakes designated as SSSI and pSPA, by end 2008.

Natural England

RSPB, RNRP

NOR_ESW_T1

NOR_ESW_SP_A3

Respond to all planning applications and other proposals subject to a consenting scheme where these have the potential to damage or destroy the features of interest of a eutrophic lake designated as LWS, SSSI or pSPA.

Natural England

The Wildlife Trust, RSPB

NOR_ESW_T1

NOR_ESW_SU_A4

Monitor the occurrence and impacts of invasive alien species (e.g. mink, white-clawed crayfish, crassula) in eutrophic habitats and where necessary, identify control measures in management plans and implement accordingly.

Site managers

Natural England, The Wildlife Trust

NOR_ESW_T1

NOR_ESW_ID_A5

Maintain a register of occurrence of alien invasive species.

NBRC

Site managers, Recording Groups

NOR_ESW_T1

NOR_ESW_RE_A6

Complete one study of the effects of diffuse pollution on designated eutrophic standing waters in Northamptonshire and produce recommendations with an action plan as necessary, by 2015.

Environment Agency or Natural England?

Anglian Water, NEN, Site Managers

NOR_ESW_T1

NOR_ESW_HS_A7

Help landowners to extend and create semi-natural habitats around the margins of eutrophic standing waters to help buffer the effects of diffuse pollution and silt, particularly through effective use of agri-environment schemes.

Natural England

The Wildlife Trust, RSPB, Landowners

NOR_ESW_T1