Threats to our hedgerows
We have seen the loss of an estimated 50% of our hedgerows since WWII.
Although the rates of direct hedge removal have been reduced, we are still seeing the loss of hedges through mismanagement. With many farmland species now marginalised to hedgerows, it’s time to look at the issues that are threatening them.
1. Neglect – under management
Hedgerows do require management in order to stop them developing into a line of trees. A line of trees doesn’t sound like a bad thing, but these become gappy and lose all the low shrubby cover that they need to provide our wildlife with shelter, food and corridors to travel.
The last countryside survey saw a massive 9% increase in the number of hedges that had been lost to this over a decade. Once a hedgerow has become a line of trees, it is very difficult to bring it back to being a hedgerow, and it will have lost many of its wildlife credentials by that point anyway, so it’s essential to prevent this structural decline.
- Over half our ‘priority species’ mammals make significant use of hedgerows for food and to travel through the landscapes.
2. Inappropriate Cutting – over management
On the opposite side of the spectrum, over-managing a hedge can also threaten our hedges. Cutting a hedge too often, and at the same height, not only reduces value of the hedge to wildlife, but also threatens the future of the hedge structure. This leads to gaps forming in the hedge which impacts their value as wildlife corridors. Cutting every year will also significantly reduce the number of flowers and fruits for wildlife to enjoy, as many of our native berry bearing species only flower on growth that is two years or older.
The timing of hedge cutting is also of huge importance to wildlife. No hedge should be cut in bird nesting season, and ideally we should wait until January where possible to trim, as this means the hedgerow berries can keep feeding our wildlife through the winter.
- 84% of our farmland birds rely on hedgerows for food and protection, and for over half of these a hedge is their primary habitat.
Ploughing too near a hedge not only destroys the herbaceous vegetation that usually grows at the base of the hedge, but it can damage the roots of the shrubs and hedgerow trees that make up the structure of the hedge. This can kill the trees and lead to the loss of parts of the hedge as the root systems are no longer able to support them, especially in times of drought.
4. Direct removal
Although the rates of direct removal have slowed in recent years, hedgerows can still be removed, with council permission, for agriculture or development. Any removal reduces how well connected the hedgerow network is.
- Birds, bats and butterflies all use hedges as foraging and commuting habitats
Herbicides sprayed too close to the hedge, or in windy conditions can kill off plant diversity, especially at the base.
- Over 500 native plant species have been recorded as being supported by hedgerows
Pesticides similarly can cause a decline in the number and diversity of insects available, which can have a knock on effect on the wildlife that they feed.
- Over 1,500 different insect species have been found feeding on or living in hedgerows, they provide a huge food resource for our birds bats and other mammals.
Fertilizers can cause a change in the type of plants growing at the hedge base. Many wildflowers do not thrive in enriched soils because enrichment causes the domination of aggressive nutrient loving plants such as nettles and docks at the expense of natural diversity.