Ditches provide a home to a wide variety of freshwater invertebrates and plants; however the conservation status and the effect of management on this habitat is largely unknown. Buglife’s ‘Grazing Marsh Ditches Project’ has broadened knowledge and understanding of ditches, and provided management advice to land owners.
Why are ditches so special?
In many parts of the British countryside, networks of freshwater and brackish ditches provide valuable habitats. Although man-made ditches support a wealth of invertebrate and plant life. Numerous wetland and water plants adorn their margins providing a refuge for a glittering array of rare water beetles, including the Biodiversity Action Plan (BAP) species: One-grooved diving beetle (Bidessus unistriatius).
Rare water invertebrates
Other BAP species found within this habitat include threatened invertebrates, such as: Fen raft spider (Dolomedes plantarius), Lesser water-measurer (Hydrometra gacilenta) and Shining ram’s-horn snail (Segmentina nitida) as well as BAP plant species, the Bird’s nest stonewort (Tolypella nidifica). Ditches also provide a habitat for a number of other rare species.
Threats to Ditches
Ditches are yet another of the UK’s threatened habitats. They are rapidly deteriorating in quality due to range of issues, including: agricultural pollution, unsuitable water level management and ‘managed retreat’ schemes on the coastline. One of the biggest problems is wholesale clearance of ditches, which is still common practice in many agricultural areas. However, until recently there has been little research and therefore a lack of understanding in regard to the effect of these issues on ditches and the rare species they harbour.
Buglife’s Ditch Project
Buglife has undertaken a suite of projects on the plants and invertebrates of ditches in coastal grazing marshes. This work was funded by the Esmée Fairbairn Foundation, the Environment Agency, Anglian Water, Peterborough & Norwich Building Society, the Broads Authority, the Courtyard Trust, the Norfolk Biodiversity Partnership, Natural England and the Countryside Council for Wales. The core project was carried out in 2007, 2008 and 2009. It aimed to assess recent changes in plants and animals and to identify management favourable to wildlife. Over 500 ditches were sruveyed in Somerset, Sussex, Kent, Essex, Suffolk and Norfolk, Gwent and Anglesey.
How has this project made a difference?
This project has produced a series of management advice sheets for land managers and professional guidance to help them support this rich and threatened habitat. These are available for download in the Download sidebar.
The final technical report for this project contains details on the classifications, conservation evaluation and change over time of invertebrate and botanical assemblages. It also contains information on species of conservation concern, details on individual marshes and the effects of environmental attributes. The final technical report ‘The ecological status of ditch systems – An investigation into the current status of aquatic invertebrate and plant communities of grazing marsh ditch systems in England and Wales’ is available to download.
For more information on the data analysis used in the report see Technical Report volume 2.
To accompany this project, four related companion projects were undertaken:
- production of a ditch survey and evaluation manual
- a bibliography of ditch surveys
- an analysis of change in Thurne catchment, Norfolk
- diatom surveys of selected ditches
The project has produced a Ditch Manual – Version 6 detailing standard methods for surveying the vegetation and aquatic macro-invertebrates of ditches. The manual describes a method for evaluating ditches utilising plant and macro-invertebrate data. The Ditch Manual – Version 6 is also available to download.