Cornish Hedge Biodiversity

Why are Cornish hedges important for wildlife?

In common with all other habitats in Cornwall, the abundance of plant species in the hedges is related to our warm winters and summers without many droughts. Cornwall enjoys a low latitude, combined with the influence of the North Atlantic Drift, with a maritime climate providing opportunities for seed germination throughout the year. A well-maintained Cornish hedge often resembles a vertical flower-meadow, as opposed to an ordinary thorn hedge which usually resembles linear scrubland. A field margin, ditch, stream or pool often interrelates at the hedge base; scrub and trees may superimpose. The combination of these habitats is of greater ecological value than each by itself. 

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Some hedges have origins in the Bronze Age, when the surrounding remnants of wilderness were present. Original species from that time still survive in Cornish hedges today.

Examples of self-sustaining relict Cornish hedge plants include elements of original woodland e.g. dog's mercury, wood sorrel and bluebell, and of original heathland, e.g. gorse, heather and tormentil.

Special to Cornish hedges are the combined effects of climate, stone, height and salt sea winds. Salt-burn extends inland from each coast as far as hill tops in the middle of Cornwall, causing the lop-sided windblown appearance and reduced height of exposed trees, and encouraging the inclusion of maritime plants. These versatile wildlife refuges were originally created by the Cornish and need to be traditionally cared for, so that they continue.

In Cornwall there are about 30,000 miles of hedges, our largest semi-natural habitat. Often with additional grassy margins and ditches, they provide a variety of conditions which elsewhere occur only in a wide range of different habitats. Across Cornwall our variety of hedges include the characteristics of flower-meadows, woodlands, scrub and wood margins, heathland, wetland, rocky outcrops and sea cliffs.

The high wildlife value of Cornish hedges results from their individual and collective habitat importance. There are more than 500 native plant species living in a widely diverse range of hedge habitats. The physical structure of Cornish hedges, especially with a grassy margin or ditch, provides a variety of conditions suitable for the flora and fauna of grassland, woodland, moorland, cliff and wetland.

  • Oak, hawthorn, blackthorn and bramble are the richest common hedgerow hosts for wildlife species.
  • Ivy gives vital autumn and winter food and shelter to many beneficial insects and birds.
  • Dead trees, topped at 3m (10ft) and left to rot away gradually, benefit invertebrates and fungi.
    The thicker and higher the hedge, the more food and safety it provides for hedge-nesting birds.
  • A good mix of native locally-occurring hedge plants yields berries and seeds throughout the winter.
  • Bushy hedges make corridors between isolated habitats, encouraging biodiversity.
  • Plenty of mature growth in the hedge harbours useful predators, eg ground beetles.
  • Trees, bushes and summer wildflowers along the hedge encourage insect-eating birds and bats.
  • Stone hedges are valuable for lichens, ferns, mosses and lizards.
  • Untrimmed growth is needed for the whole life cycles of many moths and butterflies.
  • Leaving dead twigs, leaves and fallen fruits in the hedge provides the basis for food for many insects,song birds and small mammals.
  • It is a structure that provides many differing habitats and microhabitats 
  • It is a sanctuary for species within a landscape which has been converted to intensive arable and silage fields, or urban development 
  • include a wide range of altitudes, shelter, maritime exposure and geological composition 
  • have a long and continuous history, often species-linked with the original pre-farming landscape. 
  • Provide linking refuges between other habitats.

A Cornish hedge with or without hedgerow atop can provide rich and niche habitats, many of which have shrunk from elsewhere in the landscape. Their great age results in many species being linked to pre-farming times. Whilst they are man-made they offer huge variety e.g. humus, earth, stone, dry, wet, crevices, shelter, exposure, fungi, plant life, trees, invertebrates, mammals, birds etc. 

Before 2011 the UK Biodiversity Action Plan (BAP) paid regard to the importance of managing our hedgerows properly. Hedgelink was established as the steering group for the delivery of the hedgerow management goals. It contains pages on the importance of hedgerows and their wildlife, research and surveys, legislation and hedgerows management.

Priority Habitats and Species are now listed in the UK Post-2010 Biodiversity Framework (which replaces the UK Biodiversity Action Plan). In England and Wales, hedgerows are recognised as Habitats of Principal Importance for the conservation of biodiversity under Section 41 (England) of the Natural Environment and Rural Communities (NERC) Act (2006).

The UK BAP identified hedgerows as a priority habitat. This was reflected within the national Hedgerow Habitat Plan and Cornwall’s Biodiversity Action Plan. Cornwall’s BAP focuses on the management of ancient and/or species-rich hedgerows;ancient hedges being those that define anciently enclosed land.

More detailed information about the management of Cornish Field Hedges can be found on the Field Hedge Management page.

If you would like to head outside and see what you can find in Cornish hedges read our Explore Cornish Hedges leaflet.