Manage ditches to benefit wildlife

Overall effectiveness category Likely to be beneficial
Number of studies: 4
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How is the evidence assessed?

Effectiveness

40%
Certainty

49%
Harms

14%

Calculating overall effectiveness category

Background information and definitions

Managing ditches to benefit wildlife can involve reduced or delayed cutting of vegetation on ditch banks and restricted fertiliser, herbicide or pesticide use on ditch banks or in fields adjoining ditches. ‘Bunded’ ditches are blocked to allow them to fill with water.

Study locations

Key messages

Three out of four replicated studies from the UK found that some farmland birds responded positively to the presence of ditches managed for wildlife. All three also found that some species did not respond positively or responded negatively to management.
A replicated, controlled and paired sites study from the UK found that bunded ditches were visited by more birds than non-bunded ditches.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated, controlled and paired sites study of bunded and non-bunded drainage ditches in arable and pastoral areas of Leicestershire, UK (Defra 2007), found that bird visit rates were significantly higher in bunded compared to non-bunded ditches (1.0 vs. 0.5 visits/month). Sampling involved bird observations (45 minutes, 1-2/month between April 2005 and March 2007.
Study and other actions tested
Referenced paper
Defra (2007) Wetting up farmland for birds and other biodiversity. Defra BD1323 report. Defra, BD1323.
A replicated 2010 site comparison study (Davey et al. 2010) of the same 2,046, 1 km² plots of lowland farmland in England as in (Davey et al. 2010) found that three years after the 2005 introduction of the Entry Level Stewardship and Countryside Stewardship Schemes, there was no consistent association between the length of ditches managed according to the agri-environment scheme on a plot and farmland bird numbers. Although there were higher numbers of linnet Carduelis cannabina and reed bunting Emberiza schoeniclus (two species known to nest in vegetation at the side of ditches) in plots with ditches managed according to the Countryside Stewardship Scheme and Entry Level Stewardship than in other plots, this difference was not observed for other species also expected to benefit from ditch management, including the yellowhammer Emberiza citrinella and yellow wagtail Motacilla flava. Between 2005 and 2008, skylark Alauda arvensis and grey partridge Perdix perdix declines were greater in plots with lengths of ditch management than other plots. For example, grey partridges showed decreases of 1.3 birds for each 0.08 km of ditch on pastoral farmland. The 2,046 1 km² lowland plots were surveyed in both 2005 and 2008 and classified as arable, pastoral or mixed farmland. Eighty-four percent of plots included some area managed according to the Entry Level Stewardship or Countryside Stewardship Schemes. In both survey years, two surveys were conducted along a 2 km pre-selected transect route through each 1 km² square.
Study and other actions tested
Referenced paper
Davey C.M., Vickery J.A., Boatman N.D., Chamberlain D.E., Parry H.R. & Siriwardena G.M. (2010) Assessing the impact of Entry Level Stewardship on lowland farmland birds in England. Ibis, 152, 459-474.

Please cite as:

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J. & Sutherland, W.J. (2020) Bird Conservation. Pages 137-281 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Bird Conservation

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