Habitat Creation
Removal of non-cropped land on farms has been one of the most important factors contributing to the decline in wildlife on farmland in the UK.
As an example, hedgerows and field margins have been removed to enlarge field size to increase production and maximise the efficiency of farming operations. Recently farmers have been encouraged to re-create suitable habitat for wildlife on farms under schemes such as the Countryside Stewardship Scheme, run by the Department for Environment, Food & Rural Affairs (DEFRA). A further incentive for farmers to create areas of non-cropped habitat on their land, such as beetle banks and field margins, are the potential agronomic benefits in terms of reduced pest and weed problems. On our farm we have conserved existing wildlife habitat and created new habitats to further enhance the wildlife value of our land. New habitats created on our farm, which have been funded in part by the Countryside Stewardship Scheme, include field margins, beetle banks, hedgerows, new woodland plantings and a pond.
Field margins
Field margins are particularly important habitat for wildlife, providing nesting sites for birds, refuge for small mammals and over-wintering invertebrate predators of aphids, and a nectar and pollen resource for butterflies and other insects. Sown wildflower and tussocky grass margins, and margins that have been left to regenerate naturally have all been established around the farm. The sown margins have already shown benefits both in terms of wildlife and farming:
- The wildflower margins have attracted a wide range of butterfly species onto our farm, including marbled white and small copper.
- As the margins have developed and become denser the abundance of aggressive weed species has declined.
Beetle banks
Beetle banks are linear grassy ridges created across the middle of large cereal fields. The banks do not extend to the field margin to allow farm machinery to pass and the field to continue being used as a single unit. Tussocky grass species such as cock's-foot are sown on the bank to provide over-wintering cover for invertebrate predators of cereal aphids. Beetle banks aim to increase the proportion of overwintering habitat for these invertebrates on farmland to enhance their densities in cereal fields during the spring and summer. They also aim to reduce field size to enable predators that disperse slowly by walking to fully colonise the crop before the onset of an aphid invasion. Soil sampling during the winter has shown that our beetle banks provide a suitable habitat for these predators, including ground beetles, money spiders, wolf spiders and staphylinids. Recent research by Dr. Katy James has also found that predators emigrating into the crop from beetle banks can significantly reduce aphid numbers in the crop. Furthermore, studies at the Allerton Research and Educational Trust have shown that tussocky grasses sown on beetle banks provide ideal habitat for small mammals in particular harvest mice.
Hedgerows
Long established hedgerows already exist on our farm but require continual management to ensure they retain their value in the hedgerow network. Management includes coppicing and gapping up, hedgelaying and mechanical trimming. Hedges trimming takes place on a rotational basis every third year between January and February. This regime optimises the amount of shelter and food resources for farmland wildlife, particularly during winter. New hedgerows are also being created to increase the length and diversity of linear hedgerow and provide new links with existing features.
Ponds
Ponds provide an ideal opportunity to increase wildlife diversity on farmland. A pond was constructed on our farm in October 1999 in the corner of a field that was unsuitable for growing crops. A zone of scrubby vegetation has been left around the pond to minimise leaching of agrochemicals into the pond and to provide cover for hibernating amphibians, nesting cover for wildfowl and hunting habitat for dragonflies. Water quality testing is currently being conducted to monitor nitrate levels. Little Wittenham Nature Reserve is a Site of Special Scientific Interest because of its large population of Great Crested Newts. We hope that these amphibians will spread from the reserve onto the farm and colonise the new pond.
Newly planted woodland
The large woodland area (20ha and still growing) on the farm offers considerable potential for wildlife. The primary aim of this planting is for forestry research and trials. Other areas of new plantings include the arboretum (2ha) that has been planted with native trees and shrubs. Future research will look at ways to enhance the biodiversity value of newly planted woodland.
