The importance of hedges in the Scottish countryside

These original field boundaries provide a vital habitat for wildlife to live, feed and travel across the countryside. Each hedge harbours hundreds of species and increases biodiversity across the farm or croft. In the 20th century, Scotland lost about half of its hedgerows.

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Due to targeted agri-environment schemes though, a few thousand kilometres of hedges have been created over the last few decades. It is estimated there are now around 22,000km of hedges crisscrossing the country, creating habitat for mammals, birds, reptiles, amphibians and invertebrates.

A hedge being laid

But hedges don’t only benefit nature; they help crops as well. High insect and pollinator numbers are vital for healthy yields on farms and crofts. Hedges support pollinators including butterflies, moths and bees, providing breeding habitats and improving pollination of crops such as oilseed rape, legumes and fruits. Predatory insects can also help with crop yields; they overwinter in hedgerows and move into the crops in spring as aphid numbers start to increase.

Around 30 species of birds nest in hedgerows, often those most in need of conservation such as song thrush, yellowhammer and tree sparrow. Distinct species favour different heights of hedges and use different parts: whitethroats and linnets need shorter hedges, while bullfinches need taller hedges, and wrens and dunnocks nest low to the ground.

In cereal fields, grey partridges use the thick vegetation and grass cover at the bottom to nest and in winter, hedgerows provide feeding and roosting sites for visiting species such as fieldfares and redwings.

Dog rose

The greater the variety of trees and shrubs in a hedge the better. A breadth of species gives an abundance of food through the seasons importantly pollen and nectar in late autumn, and berries in winter. The best hedges are a mix of native species such as hawthorn, and holly blackthorn with edible varieties mixed in.

Features of a good hedgerow include high density and width, connectivity to other hedges to maximise use as a wildlife corridor and a field margin between the hedge and cultivation. Naturescot advocates trimming of hedgerows only every two to three years in rotation, but ongoing management may involve re-planting to fill gaps, coppicing and laying.

Hedges are teeming with all kinds of life, and when old trees are left in situ, their dead wood, crevices and holes allow great tits, owls, kestrels and bats to nest. Bats use hedges as feeding sites and as flight paths guiding them between their roosts. Hedgehogs too use the hedge network to provide links to habitat and other hedgehog populations, as do other small mammals like voles.

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The value of hedges on farmland cannot be overestimated. Their effect on stock, soils, wildlife and pests can be seen each day, but their contribution by increasing biodiversity and helping counter the threat of climate change will be felt far into the future.

biodiversity can increase with hedges

Hedges Benefits

• Hedges provide wildlife corridors across farming landscapes and food sources for insects, small mammals and birds.

• Species-rich, mixed hedges support the widest diversity of wildlife due to the spread of fruiting and flowering seasons of the different plants.

• Hedges may support up to 80% of our woodland birds, 50% of mammals and 30% of butterflies.

• Trees in hedges provide nesting and roosting sites for birds, bats and bees and their inclusion sequesters higher levels of carbon.

• Hedges give year-round protection to stock, providing shelter in winter and in summer shade and bringing health benefits, increasing diversity in their diets.

• Hedgerows reduce soil erosion by lowering wind speeds, acting as a barrier to water runoff and helping stabilise soils with their roots.

This article originally appeared in our sister title, the Scottish Farmer.