Wildlife corridors

(hedgerows road verges sunken lanes arable field margins)

Wildlife corridors and linear features are of vital importance to biodiversity - providing a connecting framework between important habitat patches in an increasingly fragmented landscape. Through habitat loss and management change, these areas often become increasingly isolated, making it harder for flora and fauna to colonise them. These changes particularly threaten habitat specialists. Protecting and enhancing wildlife corridors may increase the ability and resilience of ecosystems to adapt to future climatic change impacts.

Hedgerows

Hedgerow types include those found at woodland edges, those found along road and track sides, and those which act as inter-field boundaries. The species mix usually depends upon the hedgerow origins. Hazel, field-maple and spindle are often from Saxon and medieval times. When hazel is dominant, the hedge tends to be older still. Hawthorn and blackthorn dominated hedges reflect planting in the late enclosures of the 17th century.

The 1994 East Hampshire Hedgerow Survey revealed that, of the trees and shrubs found within or adjacent to hedges, hawthorn was the most common, followed by dog rose and blackthorn. Suckers of elm are still a frequent and important constituent of many hedgerows. Less common species include crab apple, aspen, broom, and wild service tree.

A rich and diverse range of plants and animals are associated with, and sometimes depend upon, hedges. A great variety of butterflies, moths and other invertebrates use hedgerows for feeding, breeding and shelter. Mammals, reptiles, amphibians and birds all use hedgerows, especially at ground level as linear pathways and a place of safety. Many birds use

hedgerows for feeding and nesting, and bats use them for navigation. The 1994 survey also revealed that East Hampshire has retained a good proportion of hedgerows compared to surrounding districts, although overall length and quality is unknown. Under the Hedgerow Regulation Act 1997, it is against the law to remove most countryside hedges without the permission of the local authority.

Arable fields and margins

Field margins are the main wildlife feature within arable land and include hedgerows, and grassy verges that underlie or are adjacent to hedges. Arable fields are important for wild plants that exploit bare ground and the associated insects that pollinate them. Insects are important to birds as a food source and help maintain, for example, vulnerable populations of skylarks, lapwings and partridges. Arable weeds have suffered a significant decline in their distribution and numbers due to changes in agricultural practices over the last 50 years. The seeds of arable weeds, however, can persist in the soil to flower again if favourable management is reinstated.

In 1993, land used for cereal production within the District amounted to 10,759 ha, a 30% drop over the 1983 figure of 15,537 ha. This decline was due to the Arable Area Payment scheme that pays farmers to take arable land out of production (set-aside). There are a large number of management options that can benefit both biodiversity and the rural farming sector. Many of these, such as creating tussocky grass margins or strips, and reducing inputs around the edge of cereal crops, encourage natural crop pest predators such as spiders, hoverflies, and ladybirds.

Organic farming offers many benefits to both wildlife and rural ecosystems including rivers and soils. A number of recent reports by the Soil Association point to the tangible wildlife benefits of adopting organic techniques.

Road verges

Roadside verges and embankments may support a rich fauna and flora and replicate the conditions of semi-improved grasslands. They can support populations of wild plants such as nettle-leaved bellflower, tower mustard, shining cranesbill and several rare liverworts.

In the UK, roadside verges occupy an area of some 212,000ha and have been recorded as a breeding place for 20 of the 50 mammal species found in the UK, all 6 reptiles, 40 of the 200 bird species, 25 of the 60 butterflies, and many other valuable species. Verges must be managed in a way which is sensitive to biodiversity whilst still maintaining the safety and visibility of road users.

Some of the most valuable verges are protected as SING sites, yet even general verges may still be of great conservation value. They represent a key habitat for some of our once common meadow species such as cowslip. A number of measures could be adopted to protect verge habitats, such as sensitive mowing regimes, some of which are already in place. Native flower and grass mixes of local provenance could also be sown after road engineering works have been completed.

Sunken lanes

East Hampshire has a large number of Britain's sunken lanes. They form an important feature in the landscape, are invaluable as wildlife habitats, and are historically noteworthy. The lanes and their associated linear woods are of ancient origin with tracks between settlements being gradually worn down into the soft chalk and greensand. Ancient woodland associated with sunken lanes is of great value for flora and fauna. The depth, varied aspects and varying degrees of shade of the sunken lanes provide unique micro-climates. The mix of soils, bare rock, roots, stumps and water seepage from the land above provide exceptional habitats for flowering plants, ferns, mosses and lichens. The lanes are rich in insects, molluscs, small mammals and birds although many sites still have little or no information on them.

Over 50 miles of sunken lane have been identified in East Hampshire. The majority are on the Chalk and Upper Greensand scarps between Petersfield and Alton, while a significant number occur on the Lower Greensand around Bramshott and Rake. Others can be found north of Alton and south of Petersfield around Buriton. Many have been surfaced and serve as minor roads. Nearly all are comparatively remote.

The sunken lanes of East Hampshire are particularly important for their mosses, ferns and lichens. There has, however, been a general decline in their ecological value due to neglect, poor management, and changes in land and road use. Increasing volumes of traffic, and the size of vehicles on rural roads can have a particularly damaging effect. There are a number of other important features which could be investigated as valuable wildlife corridors including rivers and railway embankments.

The County Council identified rural verges of environmental interest through a Road Verge Management Project. These are mapped to inform contractors and receive a different cutting regime.

Other verges of importance include a number of SINCs, and those at Wheatham Hill (part of Wealden Edge Hangers SSSI).