OUR hedgreows are not at their best just now but they still have a huge part to play in protecting ecostystems says David Parish
Over the Christmas break many of us will undoubtedly head for the countryside for a walk, as a family, possibly with the dog, on the pretext of undoing the effects of some of the excesses in which we’ve indulged.
If you do, then it’s worth considering the importance of the humble hedge, and the part it plays in a healthy, balanced countryside – and how it provides, along with the grassy tussocky strips on either side and nearby woodland, an absolutely essential ecosystem for the success of many inter-dependent farmland birds, animals and insects.
While the blackthorn, hawthorn and rowan that make up the majority of our hedges may be bare but for a few berries, and the beech is clinging resolutely to its shrivelled leaves, these oases that transect our food and fuel-producing farmland also require careful management.
The Game & Wildlife Conservation Trust, through its Allerton Project at Loddington and also research at Rothamsted, has developed a considerable bank of science mapping the important interactions of habitat – both of hedges, their adjoining margins and neighbouring woodland – in providing food and cover for birds and wildlife.
A good hedge can take up to ten years to establish. Cut to an A shape with a flat top to limit the shade beneath, the hedge itself is home to birds such as finches, blackbirds and thrushes. The margins below provide nesting for grey partridge, yellowhammers, warblers, whitethroat and many other species.
These margins, if too narrow, allow easy pickings for egg predators, and an optimum width is around two metres. Sown with grasses such as cocksfoot and timothy they can give ideal cover for ground nesting birds.
But the value of a hedge also lies in its fruit and the berry crop is a tremendous source of food for the birds too. Right now the hawthorn’s dark red berries – what there are left of them – are staple diet for blackbirds, thrushes, and redwing and fieldfare that have come here for the winter from Russia and Scandinavia.
But you don’t get berries without pollination, and for that the countryside relies on bees, butterflies, wasps and other insects. So the farmer, who is farming for conservation as well as food, should also be considering devoting land to flower-rich habitats.
Success all round can be enhanced by a number of steps such as protecting the bank/margin along the hedge side, and the hedge itself, from fertilizer and herbicide drift, and using uncultivated land to encourage pollinating insects. However, here a delicate balance also needs to be struck to ensure that new flower-rich habitats do not draw pollinating insects away from existing wild plants and crops that also need to attract pollinators.
Also, woodland edges have a valuable part to play in the whole equation, particularly when the early pollinators such as bumblebees come out of hibernation and are looking for a supply of nectar from spring flowers. Hedges should also not be trimmed every year, but possibly every two to three years with sides being trimmed in alternate years to ensure that there is always a berry crop.
Farmers have an important role to play in making this habitat available – and for those farms with shoots it will be of huge benefit to them too – and there are a range of prescriptions within the SRDP to assist with hedges, grass margins and farm woodland.
The public too has a responsibility. Grassy strips at the side of hedges may look inviting for a walk with the dog or a great route on horseback but, in spring and early summer particularly, such access will disturb ground nesting birds, brown hare and other species.
Our hedges are tremendous assets in so many ways, and a lynchpin of the farmland ecosystem. Enjoy your walk!
The third Big Farmland Bird Count #BFBC takes place between 6 and 14 February 2016. The Game & Wildlife Conservation is asking people to spend 30 minutes on any one day between these dates recording the species and number of birds seen on one particular area of the farm.
Nearly 1,000 farmers, managing nearly one million acres of UK farmland, took part in the 2015 count.
Google “Big Farmland Bird Count” for more details.
• Dr David Parish, senior scientist, Scottish Lowland Research, Game & Wildlife Conservation Trust