The Creation of Woodland and Hedgerows can Play a Critical Role in Reversing Pollinator Declines

According to the largest analysis of pollinator abundance in Wales, woodland and hedgerow construction can play a critical role in reversing insect reductions that are important for crop output and other animals.

In comparison to the rest of the UK, there has been remarkably little scientific data on pollinators in Wales until now. However, a large new study including hundreds of different sites has identified the types of settings where pollinating bees, hoverflies, and butterflies thrive.

Woodland is global in the sense that it can be found on the coast, on downland, on heathland, in damp places, and in gardens, among other ecosystems discussed on this website. The main focus here, though, is old semi-natural broadleaved woodland, which covers 150,000 hectares across the UK, with lowland England particularly well-stocked.

The UK Centre for Ecology and Hydrology (UKCEH) and Butterfly Conservation Wales conducted the large-scale survey in collaboration with the Welsh Government and over 1,000 landowners across the country.

Woodlands provide a diverse environment for a wide range of species, providing food and shelter at ground level or among low-growing plants, within shrubs and bushes, and among the branches of the highest trees.

The findings demonstrate that carefully managed forest and hedgerow formation, together with other efforts like restoring wildflower meadows and organic farming with mass-flowering crops, could play a vital role in land management incentive systems.

Hedgerows are small woodlands, and many of them are centuries old. They are one of the most distinguishing characteristics of the environment, providing food, shelter, and breeding grounds as well as transportation networks that allow people to travel open areas.

More than 600 plant species, 1,500 invertebrate species, 65 bird species, and 20 animals have been identified as living or feeding in them.

Researchers found up to twice as many insects in broadleaved woodland areas as in intensively cultivated grassland in a survey of 300 squares of land across Wales measuring 1km x 1km. They also predicted that without hedgerows, pollinator abundance on agriculture might plummet by as much as 21%.

Example of Woodland and Hedgerows

Hedgerows and broadleaved woods, which include oak and maple trees as well as flowering shrubs, provide pollinators with a variety of habitats. Many woody plant species supply food for larvae and adult insects, as well as pollen and nectar.

Hedgerows and woodlands provide nesting grounds and refuge for a variety of species. Hedgerows are one of the most significant animal habitats, supporting a diverse range of birds, small mammals, insects, and plants with proper management.

Currently, woodland makes up only 15% of land cover in Wales, with grassland accounting for the other three-quarters, much of which is intensively cultivated and hence contributes little to promote biodiversity.

Woodland creation, if properly planned, is key to tackling climate change through capturing and storing large amounts of carbon. However, it also has many other benefits, including for insect biodiversity.

Dr. Jamie Alison

However, as part of its Net Zero Wales plan, the Welsh government hopes to plant 180,000 hectares of new woods by 2050.

Dr. Jamie Alison of UKCEH, who led the new study of pollinators in Wales, says: “Woodland creation, if properly planned, is key to tackling climate change through capturing and storing large amounts of carbon. However, it also has many other benefits, including for insect biodiversity.”

“The value of woodland in supporting pollinators is not widely recognized, but we find that it may be particularly important in countries such as Wales that are dominated by intensively farmed grasslands with few flowering species to support these insects.”

Dr. Alison, on the other hand, stressed the importance of maintaining a careful balance of varied habitats across a landscape in order to provide complimentary qualities that support a diverse range of wildlife.

He says: “The solution doesn’t start and end with woodland. Wildflower meadows, less intensive grassland habitats and flowering crops also play their part in supporting insects, while the type of tree cover is crucial. Timber plantations, for example, do not benefit pollinators, which thrive in the edges and gaps of natural woodland with a variety of flowering plant species.”

The study, which was published in the Journal of Applied Ecology, discovered that settings with more blooms supported higher numbers of the more than 50 pollinator species studied.

However, in places with the most flower cover, honeybees, which are excellent foragers, tended to outnumber other species. The public’s attention is mostly focused on honeybees that are kept for their commercial value.

“Although they are effective pollinators, honeybees are just one species,” says Dr. Alison. “A key finding of our study is that different approaches are needed to benefit ‘wild’ pollinators including other bee species, hoverflies, butterflies and moths which are not managed by humans.”

Around a third of worldwide food production is dependent on pollinators, primarily insects, which are necessary for the survival of other animals as well as plant populations. However, many of these insect species are declining in the UK and around the world.

According to the study’s authors, future policies and farming subsidy schemes should prioritize planting forest and hedgerow in places with poor floral cover to successfully reverse worldwide pollinator reductions.

The researchers expressed their gratitude to the many farmers and landowners who agreed to allow experiments to be conducted on their property.

Dr. George Tordoff of Butterfly Conservation, who coordinated the pollinator surveys, says “This massive, collaborative effort to survey the countryside of Wales has given us a much better understanding of the health of pollinator populations, and how this relates to different habitats, flower cover and length of hedgerows in the surrounding landscape.”