Wildlife Corridors

The state of things today

Essex is still a predominantly rural county with a landscape of arable farming. The gently rolling aspect gives a patchwork of fields, woodlands, towns and villages. Within this scene the hedgerows, ditches, embankments, green lanes and roadside verges are attractive visual features, and play an important part as vital corridors for movement of wildlife.

Historically, many of these features were a functional part of the management of the countryside, providing drainage, access, boundary security, and serving as a source of food and fuel for the local community. Many hedgerows are remnants of old forest and woodland, the rest of the wood having been cleared for grazing to leave the line of trees and shrubs to act as a stockproof boundary. Elsewhere, earth banks were dug out or thrown up to provide a more solid boundary feature, often in coppiced woodlands as a deterrent measure against browsing deer.

Ditches were dug to drain areas for grazing domestic stock or to grow arable crops. Green lanes were once the main routeway for man and his animals throughout the county. Many roadside verges have persisted for hundreds of years, while the old paths and tracks that they fringe have long-since been surfaced with tarmac.

Evidence shows that only a small percentage of these features remain intact. Hedgerow destruction over the last two decades is particularly disturbing. A recent survey showed that between 1984 and 1990 some 42,000 kilometres of hedgerow were lost in England alone. During the same time period 38,000 kilometres of additional fencing appeared and the amount of 'relict' hedgerow increased by 8,000 kilometres. This demonstrates that any claims of a decline in hedgerow destruction cannot be substantiated.

Earth banks have also declined, and by a similar percentage (17% in England) to hedgerows. Many of the remaining features are in poor ecological condition, for a variety of reasons.

Agricultural spray wash on hedgerows, the dredging and scarifying of ditches and banks and, in the case of green lanes, 4-wheel driving and motor-cycling, have ali taken their toll. Neglect is also a major cause of deterioration. These features, if they are to remain diverse wildlife habitats, need regular management. This was once part of everyday life but now has to be carried out as conservation management.

Value Added Tracts

Each of these habitats has a distinct complexity, with its own mix of associated plants and animals that are in many cases, dependent on it. In our relatively flat county earth banks constitute a significant area of steep gradient available to certain specialised plants. Animals such as badgers and mining bees, and birds like sand martins also rely on embankments in which to excavate their holes. Hedgerows are often a last refuge for plants that were once common in our woodlands. For instance, in Essex the majority of the remaining elms and wild service trees are to be found in hedgerows. Hundreds of species of insects and scores of birds displaced from the diminishing woodland are dependent on hedgerows for their food and shelter.

However, their individual value to wildlife is augmented by the role that such features play in providing a system of interconnecting corridors between other blocks of habitat. This allows movement and distribution of plants and animals over a wide area.

Evidence shows that a continuous hedgerow linking two woodlands will act as a routeway for species moving from one to the other. Speckled wood butterflies will find their way along the hedgerow quite rapidly, while bluebells seed themselves slowly, but inexorably along its length. A large gap in a hedgerow may severely limit this spread. Gatekeeper butterflies, for example, are specific to hedgerows and are reluctant to cross open ground, so a break in continuity can limit their spread. Other species will be similarly limited through discontinuity of banks, ditches and verges.

As well as these more traditional corridors, a number of other features play a part in the overall wildlife distribution network of our county. Railway lines, old abandoned and new, and motorway verges offer security from human disturbance, with the wildlife quickly adapting to the noise and wind generated by passing trains and vehicles. Industrial sites can also provide vital links, through peripheral waste ground and overgrown run-off ditches, in what otherwise would be a wildlife 'desert'. With increased preference for 'green field' sites by housing developers, gardens and school grounds take on increasing significance as corridors for wildlife between areas of countryside.

The creation of long term set-aside and wildlife headlands within the farmed landscape offers great potential as marginal habitat and as another avenue for species distribution. In addition it has been shown that such headlands have a beneficial effect on the main crop as they maintain populations of invertebrates that feed on many of the arable pest species - a means of natural biological control of pests.

Without these means of movement and dispersal, many species become isolated so that, in the event of a habitat being destroyed, there is little chance of them relocating to other suitable areas, even if these are relatively close by. Wildlife in urban areas is especially threatened in this way, being confronted with sterile concrete and tarmac in the event of displacement.

As well as being vital routes for wildlife each of these features can often influence and add to the diversity of an adjacent habitat. A ditch or earth bank running through a woodland can support a distinctly different range of species from those found in the wood itself. A hedgerow bordering grassland casts shade and influences temperature so that it may provide just the right conditions that allow a species to succeed where otherwise it would not.

The aesthetic value to the landscape of some of these features should not be underestimated. Essex does not have the hills and valleys, mountains and gorges found elsewhere in these islands. Its gentle undulations would be open and windswept without the elevations provided by hedgerows, embankments and green lanes or the shelter afforded by ditches.

Targets for 2000

• Identify, protect and maintain all valuable hedgerows, green lanes, old earth banks and roadside verges.
• Increase the legislative protection for wildlife corridors, and support existing protective measures such as SSSIs and SINCs.
• Increase the current length of wildlife corridors in the county by 10%. This would mean the protection and management of an additional 1 300 km of hedgerow, 7,200 metres of roadside verge and the creation of approximately 120 km of earth banks
• Improve the management of existing wildlife corridors for the benefit of nature conservation and landscape.
• Increase awareness of the value of school grounds, gardens and industrial areas as potential wildlife corridors. Offer advice on setting up habitat creation schemes to enhance this potential.
• Push for the provision of wildlife corridors to be incorporated in to all future urban development plans,' with an ongoing financial and physical commitment to their maintenance by the developer or local authority.

Hedgerows

• Campaign for the establishment of new legislative protection for hedgerows.
• Encourage planting of new hedgerows to replace lost sites. Such hedgerows should be comprised of suitable native species of trees.
• Support those schemes and projects such as ESAs, Countryside Stewardship schemes and Farm Hedgerow Schemes, which already exist and campaign for further support for replacement of lost hedgerows.
• Encourage more sympathetic management of existing hedgerows using traditional techniques of coppicing, pollarding and laying as a replacement for the modern "bush-whacking" machinery.

Roadside Verges

• Identify and protect any roadside verges within the county that are of high conservation value.
• Essex County Council in cooperation with the Essex Wildlife Trust already operate a Roadside Verge Scheme which forms the basis for existing identification and protection of roadside verges. More effective protection, including legislative protection needs encouraging through this and other schemes.
• Encourage good management practices with all parties responsible for roadside maintenance.

Green Lanes

• Promote and encourage planning protection for existing green lanes.
• Identify and highlight existing green lanes and where applicable campaign for their protection.
• Encourage the planning and establishment of new green lanes, through imaginative planting and management, with long term protection under a local or regional structure plan.
• Develop ways of mitigating the problems caused by conflicting public use of green lanes (walking, riding, motorcycling and 4-wheel driving) to prevent erosion and damage to the wildlife in these lanes, yet maintaining their purpose as a public right of way.
• Highlight the loss of green lanes within Essex and promote better management of such features by sympathetic means rather than mechanical cutting of vegetation and surfacing of the trackway.

Ditches and Earthbanks

• Identify earthbanks that are of high conservation value in the county.
• Promote the need for protection of such sites which are of equivalent value to the landscape as green lanes and hedges.
• Ensure that new earthbanks and ditches are created on sites that are not damaging to existing conservation value, and in such a way as to enhance their potential for wildlife.
• Campaign for a set-aside style of ditch management that will encourage farmers and landowners to leave stretches of their ditches suitably managed for a number of years in the interest of greater wildlife diversity.