Farmland Habitat Audit
Threats and Opportunities, Data Sources, Rationale and limitations
Threats and Opportunities
Threats
The threats to farmland biodiversity have been well documented; indeed the
rapid decline in once familiar farmland birds was one of the main catalysts for
the biodiversity action planning process in the UK.
In recent years the primary threat to farmland biodiversity in London, in common with the rest of the UK, has been continued agricultural intensification driven by advances in technology and falls in farm incomes. Application of artificial fertiliser and the widespread use of herbicides and insecticides have resulted in a severe decline in the biodiversity of intensively farmed fields. Simplification of the crop rotation cycle - including the decline in the use of root crops in stock rearing areas, use of pre-emergence weed killers, rapid re-seeding of grassland in rotation cycles, change from spring to autumn sown cereals and the switch from hay to silage production – has taken its toll on farmland wildlife.
However, these widespread changes in farming practice are not the sole threat to farmland biodiversity. Loss of farmland to outdoor leisure activities (e.g. golf courses) has become a significant issue in recent years and the need for new cemetery space may impinge upon the farmed landscape in the years to come. The rise of ‘horsiculture’ in London’s Green Belt has caused many pastures to be subdivided, frequently resulting in severe overgrazing.
In addition to the above threats, which are driven largely by strategic policy decisions, farmland biodiversity is threatened at a more local scale by a variety of small-scale impacts with a significant collective effect on certain habitats or species. These include:
 | Ill-considered tree planting schemes. These are often targeted at marginal agricultural land, rough grazings etc. with little consideration of the nature conservation value of the existing habitat. |
| Various ‘urban fringe’ pressures such as illegal motorcycling rubbish dumping and disturbance. |
| Continuing small-scale loss of remnant semi-natural habitats by, for example, regular flailing of hedgerows or neglect of hedgerows; drying out or over-shading of ponds; tidying of headlands and marginal areas and over-deepening of ditches, etc. |
A more subtle threat, perhaps, is the lack of awareness and understanding of farming and the agricultural landscape (and, thereby, the biodiversity which still occurs there) amongst the increasingly urban perspective of the majority of London’s population.
Opportunities
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.
Data Sources
Archer J. & Curson D. (1993). Nature Conservation in Richmond upon Thames. Ecology Handbook 21, London Ecology Unit.
Association of London Government (1997). Association of London Government Directory 1996-1997. Published by ALG.
Farino, T. & Game, M. (1988). Nature Conservation in Hillingdon. Ecology Handbook 7, London Ecology Unit.
Farino T., Pagendam C. & Swales S. Frith M. (1989). Nature Conservation in Harrow. Ecology Handbook 13, London Ecology Unit.
Hewlett J., Yarham I. & Curson D. (1997). Nature Conservation in Barnet. Ecology Handbook 28, London Ecology Unit.
London Planning Advisory Committee (1994). Advice on Strategic Planning Guidance For London. Published by LPAC
London Research Centre (1999). Focus On London. LRC.
Ministry of Agriculture, Fisheries and Foods (1965). Agricultural and Horticultural Returns- Final Results Of The June 1965 Census In England And Wales. MAFF Statistics.
Ministry of Agriculture, Fisheries and Foods (1985). Agricultural and Horticultural Returns- Final Results Of The June 1985 Census In England And Wales. MAFF Statistics.
Ministry of Agriculture, Fisheries and Foods (1995). Agricultural and Horticultural Returns- Final Results Of The June 1995 Census In England And Wales. MAFF Statistics.
Ministry of Agriculture, Fisheries and Foods (1998). Final Results of the June 1997 Agricultural and Horticultural Census: England and Wales, Regions and Counties. MAFF Statistics.
Ministry of Agriculture, Fisheries and Foods (1998b). The Digest of Agricultural Census Statistics United Kingdom 1997. MAFF Statistics.
Ministry of Agriculture, Fisheries and Foods (1999). Agricultural and Horticultural Census: 1 June 1998 United Kingdom. MAFF Statistics News Release (Stats 8/99).
The UK Steering Group (1995). Biodiversity: The UK Steering Group Report. Volume 2: Action Plans. HMSO.
Wicks, D. & Cloughley, P. (1998). The Biodiversity of Southeast England: An Audit And Assessment. Hampshire and Isle of Wight Wildlife Trust.
Rationale and limitations of approach
The farmland audit should be used as a guide and not as a definitive statement of Greater London’s farmland resource. Data was provided by MAFF. This data represents the most fully comprehensive data available. Totals were available for farmland in London as a whole (see Table 1), which provides an overview of the resource. The data provided by MAFF has enabled land use comparisons to be made between 1997, 1985 and 1965 for both Greater London and the Southeast Region.
Individual totals were not available for each borough due to data protection mechanisms (where land holdings within a parish are too small or farmers may have requested a non- release of data policy). However, data for the following boroughs was available: Barnet, Bromley, Enfield, Havering and Hillingdon. The borough data provides an indication of the outer London farmland resource.
The Institute of Terrestrial Ecology holds satellite data on land uses in Greater London. This data has been used by the London Research Centre (LRC) in the production of their Focus on London Report (1999). In this report, percentages of land cover types were estimated for each 1 km grid square. However, there are drawbacks to this approach caused by limited resolution and inclusion of land outside of the Greater London boundary (data from entire grid squares was included even when it fell outside the Greater London boundary). The latter results in exaggerated figures for Greater London. This can be illustrated by comparing the LRC total for agriculture, which is 13,600 ha and the total for agriculture taken from 1997 MAFF data - 12,872 ha.
Satellite data is useful for gaining a quick overview of Greater London land use but does not enable the more detailed assessment provided by the MAFF data. Furthermore, MAFF data is based upon the 1997 ‘returns’ and provides the most up to date view available, the satellite data dating from 1988 and 1991.
Coverage of the MAFF Census The 1997 annual June survey covered 237,720 agricultural holdings in the United Kingdom. In England only main holdings were surveyed. The MAFF definition of a ‘holding’ is "land on which agricultural activities are carried out and which is by and large farmed in one unit having regard to such supplies as machinery, livestock, feeding stuffs and manpower, and to the distance of any separate areas of land involved and their type of farming" (MAFF 1998b).
The survey aimed to estimate the aggregates of individual items collected. To this end, ‘minor’ holdings are excluded in England as they contribute only a small proportion of the totals and are therefore considered statistically insignificant.
A holding is classified as minor if all the following criteria are true:
| The total area is less than 6 hectares |
| There is no regular whole time farmer or worker |
| The estimated annual labour requirement is less than 100 days (of 8 hours productive work by an adult worker under average conditions) |
| The occupier does not farm another building |
| The glass house area is less than 100 square metres |
If any of these conditions are not satisfied the holding is considered as ‘main’. So although the MAFF data represents the most comprehensive and up-to-date data available there will still be a shortfall in terms of the farmland resource represented by these statistics. As the LRC data over-estimates the resource it is fair to say that the total for farmland within Greater London lies somewhere between the LRC figure of 13,600 ha and the MAFF figure of 12,782 ha.