A recent study published in the journal Ecological Solutions and Evidence suggests that reintroducing wolves to the Scottish Highlands could play a role in combating climate change. Scientists from the University of Leeds' School of Earth and Environment conducted the research, marking the first time the impact of reintroducing wolves on woodland expansion and carbon storage in the UK has been recorded.
"We found that wolves would keep down the numbers of deer, and that would leave more young trees to grow, so the woodlands would expand," said Professor Dominick Spracklen, who led the research team, according to BBC News.
Red deer in Scotland have been without natural predators since wolves were exterminated from the mainland in the 17th century. This absence has allowed the red deer population to increase, with recent estimates suggesting there are about 400,000 red deer in Scotland. These deer consume saplings and damage older trees by stripping them of bark, inhibiting the natural regeneration of forests.
Currently, Scotland has one of the lowest levels of native woodland in Europe, with only 4% of the country covered, making it one of the least forested parts of the continent, according to The Guardian. The lack of natural tree regeneration has contributed to the long-term decline and loss of native woodland in Scotland.
The study estimates that reintroducing about 167 wolves in the Cairngorms and across the Highlands would be sufficient to suppress red deer populations. The presence of wolves would reduce red deer densities to below four per square kilometer, allowing trees to begin natural recolonization and leading to the expansion of native woodland forests, as noted by IFLScience.
This expansion of native forests could have climate benefits. Increased vegetation from the expansion would reduce the concentration of carbon dioxide in the atmosphere. The study estimates that the forests could absorb about one million tons of CO₂ annually, contributing to approximately 5% of the carbon removal target for UK woodlands suggested by the UK's Climate Change Committee to reach net-zero by 2050.
Each wolf would contribute to an annual carbon uptake of 6,080 tonnes of CO₂ and is valued at around £154,000 based on current carbon valuations. The financial benefits associated with carbon uptake and storage would be in addition to other well-documented economic and ecological impacts of wolf reintroduction.
Professor Spracklen emphasized the interconnectedness of climate and biodiversity issues. "There is an increasing acknowledgment that the climate and biodiversity crises cannot be managed in isolation," he said, as reported by The Independent. "We need to look at the potential role of natural processes such as the reintroduction of species to recover our degraded ecosystems and these in turn can deliver co-benefits for climate and nature recovery."
The researchers acknowledge that the idea of reintroducing wolves is controversial and would require careful management near human populations or livestock. "Human-wildlife conflicts involving carnivores are common and must be addressed through public policies that account for people's attitudes for a reintroduction to be successful," said Lee Schofield, a co-author of the study, according to The Guardian. "We recognize that substantial and wide-ranging stakeholder and public engagement would clearly be essential before any wolf reintroduction could be considered."
Despite culling and hunting efforts, red deer numbers in Scotland have continued to increase in the absence of their natural predators. At high deer densities, natural regeneration and colonization of woodland is largely restricted to areas where deer are excluded by fencing. More intensive deer management in certain locations has helped improve tree regeneration, and more saplings appeared when red deer numbers were reduced to fewer than four per square kilometer.
The wolf population in Western Europe now exceeds 12,000 and occupies about two-thirds of their former historical range, including human-dominated landscapes in Central Europe. Wolves have returned to countries like the Netherlands, which is more densely populated than Scotland, indicating the feasibility of their return to the UK.
"Deer, in combination with sheep in some areas, prevents tree regeneration across much of Scotland," the University of Leeds team wrote. The absence of large predators like wolves has led to ecological knock-on effects, including the long-term decline and loss of native woodland in Scotland.
The reintroduction of wolves could also lead to a reduction in Lyme disease related to ticks carried by deer, as well as a reduction in deer-related traffic accidents. However, some farmers and rural communities are opposed to the measure, and controversy is particularly expected among livestock farmers and deer stalkers.
Discussions around potential large carnivore introductions to the UK and elsewhere are ongoing. The researchers believe the results provide further evidence of the role large carnivores can play in delivering nature-based solutions to address the climate emergency. They argue that the benefits of reintroducing wolves must be considered, including the financial benefits associated with carbon uptake and storage.
"Our aim is to provide new information to inform ongoing and future discussions about the possibility of wolf reintroductions both in the UK and elsewhere," said Lee Schofield. "We recognize that substantial and wide-ranging stakeholder and public engagement would clearly be essential before any wolf reintroduction could be considered."
The article was written with the assistance of a news analysis system.