Rethinking the Humble Ditch: Science-Backed Management for Nature Recovery

Copy-write Glynis Pierson

Copy-write Glynis Pierson

Global evidence for the effects of conservation actions to manage ditches for biodiversity 

Vanessa Cutts, Matilda Parr, Rebecca K. Smith, and William J. Sutherland

Ditches are often dismissed as simple drainage channels, but they are the lifeblood of our agricultural and lowland landscapes. From the rare Norfolk Hawker dragonfly to breeding amphibians, these waterways are biodiversity hotspots—if managed correctly.

In partnership with FenlandSOIL and Conservation Evidence we have collated global evidence to understand which management actions actually work for wildlife.

Evidence doesn't provide a 'one-size-fits-all' instruction manual, but it does empower us to make better decisions for the future of our landscapes.

Link to Report

The Research 

Our colleagues from Conservation Evidence reviewed 48 potential conservation actions, drawing from 97 scientific studies worldwide (with 70% based the UK & Europe); to provide evidence-based insights for farmers, land managers, and policymakers.

Fenland Dragonfly

Key Takeaways

  • Less is More: Reducing the frequency & intensity of dredging & mowing generally leads to higher biodiversity.
  • Chemical Control: Reducing fertilizers & pesticides near ditch edges is one of the most effective ways to boost plant life.
  • Context is King: What works in a highland stream might not work in the highly connected, modified waters of the Fens.
  • Scheme Gaps: Current Agri-Environment Schemes (like SFI or Countryside Stewardship) are a great start, but they often miss the "big wins" like large-scale rewetting or ditch reprofiling.

What the evidence suggests

Ditch Maintenance & Cleaning

While cleaning temporarily disturbs the ecosystem, it can prevent ditches from disappearing entirely.

  • Amphibian Boost: Frogs and toads often thrive in the two years following a clean, as it opens breeding space.
  • The Right Tools: Using a ditch-scoop or mowing basket supports higher plant richness than more aggressive industrial methods.
  • Timing: Mowing later in the year (July–September) allows plants to set seed, dramatically increasing future diversity.

Restoring Habitats

To truly move the needle on nature recovery, we need to look at the shape and wetness of the land.

  • Buffer Strips: Creating "no-spray" zones alongside ditches significantly enhances dragonfly diversity and water quality.
  • Rewetting: Blocking or damming ditches can return vegetation to natural, undisturbed levels within just three years.
  • Connectivity: In the Fens, water moves between farms constantly. This means local successes can be overwhelmed by "diffuse pollution" from further upstream—highlighting the need for landscape-scale cooperation.

Insights from the Field

Scientific data is vital, but so is the "boots on the ground" experience of Fenland practitioners. Our site visits highlighted practical wins:

  • The "One-Side" Rule: Cutting vegetation on only one side of a ditch per year creates permanent wildlife corridors for water voles and warblers while halving management costs.
  • Plastic Piling: A quick, durable, and cost-effective way to block ditches for peatland rewetting compared to traditional timber.

The Report

This research was part of the Lowland Agricultural Peat Water Discovery Pilot, funded by the Environment Agency and Defra. We believe that by bridging the gap between scientific evidence and farm management, we can turn drainage networks into thriving nature networks.

Link to Report

Read more about our work in the Fens

This study forms part of a wider programme of CLR research in the Cambridgeshire Fens, exploring how different land management choices influence ecological processes, environmental outcomes, and the future of our landscapes. Related work includes The Hidden Climate Impacts of Ditches and Canals, which investigates greenhouse gas emissions from ditches and canals, and Lines in the Landscape, which highlights the overlooked role of water channels in shaping ecosystems, soils, climate processes, and human societies.

Taken together, these studies provide a more comprehensive understanding of how land and water management in the Fens can support biodiversity, climate goals, and sustainable landscapes.