Hedgerow Heroes
Besides old-growth trees and rainforests, a common green growth that we may see daily in the UK also plays a big part in combating climate change. Maddy tells us more about the significance of hedgerows in the climate fight.
Illustrated by Aimee Lee.
Reading The Tales of Brambly Hedge when I was little was probably my first introduction to a hedgerow and how they can help support the lives of the creatures teeming within. From providing a banquet of winter berries for mice, to a cosy cover for a hibernating hedgehog to a navigation system for a meandering bat. But what about the importance of hedgerows on a larger scale?
For fear of pointing out the obvious, a hedgerow is a strip of woodland edge habitat and the original purpose of hedgerows way back when, was to mark boundaries and keep livestock. Some of the oldest surviving hedgerows, such as those in Cornwall, are as old as 4,000 years! Now we understand that they have so much more potential. Hedgerows are classed as a priority habitat on account of them having huge importance for biodiversity and conservation, as well as contributing ecosystem services which provide tangible benefits for us humans.
Hedgerows play a role in combating climate change. If we could increase hedgerow habitats by 40% it could help us to reach our goal of zero net greenhouse gas emissions by 2050. This is because as plants photosynthesise they exchange carbon dioxide for oxygen, meaning the roots of the hedges, as well as the other vegetation interspersed within them, stores carbon away from the atmosphere. The oxygen produced during this process also helps to improve air quality.
The shrubs and flowers that are part of a hedgerow are also vital in supporting pollinator species, such as our declining bee population. They provide insects with more opportunities for nectar and pollination which is important for food production and the plants’ own reproductive success. It also means they are less dependent on crops which could have been sprayed with harmful insecticides. A study tested how hedgerows influence pollinator movement by using fluorescent dye to track them between cornflowers found along a hedgerow and across it into adjacent fields. More dye was found along the hedgerows compared to across the hedgerows and into the fields, even with similar numbers of pollinators. This suggests hedgerows are important for pollinator movement and pollination opportunities. Interestingly, this paper also concludes that hedgerows can have unexpected and potentially undesirable effects; they could act as a barrier to pollination as pollinators are sticking to hedgerows and not venturing to the adjacent fields. Therefore when thinking about agricultural land management, the right balance needs to be struck between having connecting hedgerow habitats and also encouraging the wider dispersal of pollinators to ensure pollination of crops.
Hedgerows provide other ecological benefits such as reducing flooding, preventing soil erosion and generally keeping soil healthy. Their roots “knit” the soil together to help keep it in place and they provide a physical barrier that stops fertile soil running off the land during heavy rainfall. Keeping soil in place like this is extremely important as one inch of soil can take 500 years to form and soil erosion and degradation costs the country millions each year. Healthy soil also helps in mitigating climate change as it stores carbon.
As well as providing food and shelter for the creatures that dwell there, hedgerows also act as a “corridor” between habitats – almost like a sat-nav for the animal kingdom. This is especially important in the face of the climate and ecological crisis. Habitats are being lost and becoming more isolated (known as habitat fragmentation) and animals are having to change their behaviour in response to environmental pressures, but the presence of hedgerows aids the connectivity of these habitats and the movement between them. To illustrate the importance of connectivity, a study used a simulation to compare whether it is more effective to restore existing connecting habitats, such as hedgerows, or create new ones. The simulation was based on a real area in Northern Italy and used the hazel dormouse as its target species. The results showed that actively creating new hedgerows resulted in larger connectivity gains (40% increase) compared to restoring existing connecting habitats (11% increase).
However, that isn’t to say that the quality of existing hedgerows isn’t also important. After the Second World War, the removal of hedges was encouraged by the government to help Britain develop a self-sufficient food supply. Since 1945, this intensification of farming combined with poor hedge management has contributed to the decline of hedgerow conditions. Hedges are cut too frequently and severely, which leads to the dreaded gaps in connectivity, and planted with just one or two plant species, which will not be able to support the 130 species of conservation concern which rely on hedges. Only 1 in 3 hedgerows in England are in good condition.
All of this to say, in a nutshell, is that hedgerows are indispensable. Did you know that if you put all the hedgerows in the UK in one long line, it would be longer than the length of all the roads in the UK combined? That’s a lot of potential for carbon storage and habitat connectivity. So what’s being done to help protect and conserve them? Well, first of all there’s the Hedgerow Regulations (1997) in the UK which means that it is illegal to remove or destroy countryside hedgerows without permission if they are more than 20 meters long, more than 30 years old, or have a specific number of woody species and/or associated features. Cornish hedgerows are an example of hedgerows which have an associated feature, ie. a wall. This can make it hard to classify and protect them because they are mainly wall with just perhaps a few woody species on top. Weirdly, the legislation also doesn’t specifically define a hedgerow which can make things awkward, what with the huge variation in types of hedgerows.
There’s also a drive to collect more data on hedgerows through projects such as The Great British Hedgerow Survey launched by the People’s Trust for Endangered Species and Hedgerow Heritage run by Surrey Wildlife Trust. These campaigns encourage people to get involved and become citizen scientists by surveying hedges in their local area and actively helping to restore them. Collecting up-to-date information about hedgerow health like this means we can focus our conservation efforts and continue to educate people about these hedgerow heroes.
Maddy Simmonds
Maddy is a Zoology graduate from the University of Exeter and her passions include conservation, anthrozoology and science communication. She often draws inspiration from connecting with nature in everyday life and hopes to encourage people to also be just as excited by local conservation stories as international ones. She enjoys how writing not only allows her to share information with others, but that she is also able to learn new things for herself in the process
You can follow Maddy on her nature-based instagram account @nature_nutter.