Our findings suggest that wild boar, while important for ecosystem dynamics and functioning, may not be a silver bullet for boosting both soil carbon or plant diversity. Instead, they appear to favour plant communities that can reduce carbon storage potential.”
Connor Lovell, lead author and a PhD student from King’s College London
18 July 2025
Reintroducing wild boar could reduce soil carbon storage
Resurgent in Scotland, boar may not be a silver bullet for restoring natural habitats.
Wild boar, often hailed as ‘ecosystem engineers’ in rewilding projects, could in fact be reducing soil carbon storage by promoting fast-growing plant species.
A new study led by researchers at King’s College London and the ZSL (Zoological Society of London) is the first to provide empirical evidence that wild boar indirectly lower soils organic carbon by altering plant community traits – highlighting the importance of careful, evidence-based planning for rewilding projects.
The research, published in Ecological Solutions and Evidence and conducted at the Bunloit Rewilding Project near Loch Ness, found that areas more frequently visited by wild boar were dominated by plant species that grow quickly and decompose rapidly - leading to lower levels of organic carbon stored in the soil.
Wild boar populations are increasing across Europe through range expansions, reintroductions, and escapes from farms. Their rooting and foraging behaviours are known to disturb soil and vegetation, but until now, the indirect effects on belowground carbon had not been fully understood.
The study, which used camera traps and soil sampling across 72 plots, tested two hypotheses: that boar would increase plant diversity and that they would shift plant communities toward fast-growing species.
Only the latter was supported. While boar presence did not significantly affect plant species richness or diversity, it was linked to a shift in plant traits that correlated with lower soil organic carbon.
“This doesn’t mean wild boar are bad for ecosystems,” said co-author Professor Terry Dawson, a Professor of Global Environmental Change at King’s College London. “But it does highlight the need for diverse communities of hoofed mammals in rewilding projects to balance ecosystem functions like carbon storage and biodiversity.”
Indeed, the study found that landcover type—such as woodland or coniferous plantation—had a much stronger influence on soil carbon than wild boar activity.
Additionally, the researchers caution that the effects of wild boar on ecosystems are context-dependent and influenced by factors like climate, plant traits, and land management.
As governments and conservationists increasingly turn to rewilding as a tool for climate mitigation, this study underscores the complexity of how an ecosystem might respond.
The authors advocate for rewilding strategies that include a mix of herbivores with different feeding behaviours to optimise both biodiversity and carbon storage.
“Successful rewilding isn’t just about bringing animals back,” said Connor “It’s about understanding how those animals influence the environment to promote dynamic and resilient ecosystems.”
Read the paper:
In this story
Professor of Global Environmental Change