Farmland habitat audit

Farmland can be broadly defined as land under cultivation that is tilled at least once every five years. This can include land in set-aside, or temporary grassland (an agricultural ley).

In 1997 MAFF estimated approximately 12,872 ha of farmland in Greater London (seeTable 1), 529 ha of which was under set-aside. The total area of farmland in London represents 8% of the total area of Greater London. There are estimated to be 1,156,114 ha of farmland in Southeast England; London accounts for just 1% of this. MAFF's 1997 figures show that the majority of farmland in London is made up of arable (27%) and grassland (44%, excluding rough grassland).

The overall farmland resource in London declined by 30% between 1965 and 1997. This included declines in arable of 42%, orchards 90%, bare fallow 75%, grassland (excluding rough grazing) 22% and rough grazing 39%.

The intensification of farming over the last 20-30 years (and the reduction in farmed land in London) has led to significant nation-wide declines in many species dependent upon habitats associated with `traditionally' farmed landscape. This has led to farmland habitats being highlighted as a priority for nature conservation by the UK Biodiversity Steering Group (1995). Of particular nature conservation importance are traditional hay meadows, old hedgerows and ponds, and farmland birds such as tree sparrow and skylark.

Although most mammal species are found within a range of habitats in London, the remaining populations of brown hare are virtually confined to arable areas on the fringes of the Capital.

There are few plant species with specific associations with agricultural land which still occur in London, largely due to the use of herbicides. However, some of these species (such as poppy Papaver rhoeas) are making a welcome comeback as a result of Countryside Stewardship and set-aside schemes. Rarities such as Deptford pink Dianthus armeria may survive as viable seed in the seed-bank in the margins of arable land on the chalk. It is perhaps interesting to note that many plant species formerly regarded as weeds of arable land are now more often encountered on wasteland sites across the Capital.

Much of the nature conservation value of 'active' farmland has become concentrated in the field margins, headlands and along field boundaries, particularly hedgerows. These remaining semi-natural habitats often support populations of common grassland butterflies such as gatekeeper and a host of other invertebrates which are an important food source for farmland birds, particularly during the breeding season.

The opportunities for effecting biodiversity conservation and enhancement on farms are almost as well documented as the litany of losses of biodiversity throughout the agricultural landscape. Various agri-environment schemes across the UK, such as set-aside and Countryside Stewardship, ensure that some farmland areas are maintained more favourably for wildlife. In addition, some areas of intensively farmed land have been targeted for reversion to more 'traditional' farming methods including organic farming, in an attempt to restore priority habitats and species.

Countryside Stewardship and other agri-environmemt schemes are in place on some farmland in Greater London - there has been a particularly good uptake in Bromley for example. Promotion of these schemes and targeting of important sites in the urban fringe needs to continue. A review of current agri-environment schemes might be beneficial, with a view to identifying mechanisms for combining opportunities for biodiversity conservation and recreation/amenity in the urban fringe.

The recent economic crises in the farming industry and the ongoing debate concerning the perceived need for a large number of new homes (particularly in and around London) has highlighted the potential resource provided by London's farmland. These agricultural landscapes could provide tremendous potential for biodiversity conservation as part of a holistic approach to the management and enhancement of London's Green Belt. The two Community Forests on the fringes of London (Thames Chase in the east and Watling Chase in the north) provide a model for this approach, although biodiversity has not been an integral theme in the respective 'Forest Plans' to date.