Hedgerows are so teeming with life that one study counted 2070 species in one 85 metre stretch. Even this was thought to be an underestimate, as many taxonomic groups were not thoroughly sampled.
Whole books have been written about the wildlife that live, feed and travel in the hedgerows of this country and still they barely scratch the surface. The importance of our hedgerow network cannot be overstated, especially at this time where we are seeing worrying declines in our native wildlife across the board.
Amongst all the other benefits the humble hedge offers us, hedgerows provide three vital services for wildlife.
1) They provide a physical home
to many creatures, from nesting birds, hibernating hedgehogs, dormice and other small mammals, to insects like beetles and butterflies. An enormous 70% of our landscape is farmland, and within that hedgerows are one of the only remaining semi-natural homes that wildlife has. Consequently, many of our farmland species are now marginalised to hedgerows.
2) They are an excellent complementary habitat
one that is not necessarily home but plays an important role in life. This can be for food, such as leaves, flowers, berries, insects or small mammals, or it could be shelter from predators or the elements whilst out foraging.
3) They are a route of passage, connecting up the landscape
they criss-cross the country enabling wildlife to move about the landscape. This is so important as it connects populations that would otherwise be isolated and vulnerable. Bats both use hedgerows as feeding sites, but also use them as flight paths to commute between their roosts and other suitable foraging sites. Butterflies and other flying insects take advantage of the shelter hedges provide to be able to fly. Dormice, which are predominantly arboreal rely on the connections of good hedges to move between other suitable habitats to breed and feed.
From the herbaceous vegetation at the bottom, to the woody shrubs that make up the structure and the trees, all the parts that make up a hedge play a role. Find out more about how individual elements of hedgerow structure affect how wildlife can use them.
Over 500 plant species, 60 species of nesting bird, many hundreds of invertebrates and almost all of our native small mammal species have been recorded as being supported by hedgerows.
Here are some of the headline findings from a wealth of studies showing the profound importance of our hedges for wildlife.
Dormice and hedgerows
Hedgerows play an important role for dormice. In spring blackthorn and hawthorn flowers are used as food, then in early summer ash keys, honeysuckle flowers and insects such as aphids are eaten. Later in the year they rely on blackberries and hazelnuts to build fat reserves for the coming winter. The diversity of hedgerow plants is therefore vital in supporting dormice.
There has been a 64% decline of dormouse occurrence in hedgerows since the late 1970s.
Hedgerows are also used as dispersal corridors and are an important link between copses that are too small to support a viable dormouse population on their own. Crucially they also support breeding populations independent of other habitats. Even small gaps in a hedgerow can be an obstacle to dormouse dispersal.
Dormice can be quite specific when it comes to which hedge they nest in, they require a diverse range of plant species and only appear to nest in hedges that are left to grow a little larger. Some good hedges have been seen to maintain dormice in densities comparable to woodland.
Hedgehogs and hedgerows
As the name suggests hedgehogs are often found near hedgerows. They provide ideal locations for nest sites, a good supply of invertebrates on which they feed, protection from predators and important movement corridors. The pastures used by farmers to raise cattle, sheep or horses are important foraging areas for hedgehogs.
Bats and hedgerows
Bats use hedgerows as feeding sites, exploiting their increased populations of flying insects and they also use them to travel from their roosts to other feeding sites. Especially for bats with limited echolocation ranges such as the Pipistrelle, having a network of well connected hedgerows near their roosts is very important.
All the bat species that live in the UK are protected species, and our hedgerow network is important for their future survival.
Hedgerows can also break up wind speeds, which can be important in exposed areas. Without hedgerows, insects can struggle to fly on windy nights which reduces the amount of prey available for the bats.
Hedgerow trees can also be valuable roost sites for some species of bat which can live in rot holes or in crevices in the bark. We are seeing the loss of our hedgerow trees, and also a lack of new ones being allowed to emerge which will have an impact of a wide range of species that call them home, including bats.
Birds and hedgerows
Hedgerows are hugely important for our native birds, providing roosting, nesting and feeding opportunities that can otherwise be scarce in our agricultural landscape. As many as 16 of the 19 birds included in the Farmland Bird Index, used by Government to assess the state of farmland wildlife, are associated with hedgerows. 10 of which use them as a primary habitat
The number of bird species, as well as the number of individual birds tends to increase with the size of the hedge and the number of woody species of plant that the hedgerow is made from. As shrubs flower and fruit at different times throughout the year, having that variety means there is a longer period where food is abundant. Hawthorn and dog rose are particularly valuable shrubs for providing food that can last throughout winter.
The base of a hedge is really important for many nesting bird species, a dense hedge with good cover especially in the lower 1m of the hedge increases bird numbers and the number of territories. Similarly the height of a hedge can also have a big impact on the numbers and the diversity of nesting birds, with taller hedges generally supporting increased diversity and numbers of nesting pairs, possibly through the reduced chances of predation.
Trees are important for many bird behaviours, and are used as song-posts and territory markers. These hedgerow trees also support a huge quantity of invertebrate life that help feed our insectivorous bird species.