A Rare Butterfly Could Become a Key Indicator of Peatland Health

A conservationist in Wales is leading a major new study to find out whether the endangered large heath butterfly could become a powerful natural indicator of climate change and peatland health.

Georgina Paul, from Butterfly Conservation, is halfway through a two-year research project exploring whether this rare butterfly species can reveal how well Welsh peat bogs are coping with rising temperatures and restoration efforts.

Often described as a possible new “canary in the coal mine” for climate change, the large heath may provide vital clues about the condition of one of the UK’s most important carbon-storing habitats.

Why Peatlands Matter in the Fight Against Climate Change

Peatlands are among the most important natural carbon stores on Earth. When kept in a healthy, waterlogged condition, they trap and hold vast amounts of carbon dioxide, helping to slow global warming.

However, when peat bogs dry out due to climate change, drainage or land damage, they begin to release stored greenhouse gases back into the atmosphere.

This makes peatland restoration in Wales a crucial nature-based solution for tackling the climate crisis while also protecting biodiversity.

Large Heath Butterfly Monitoring Across Wales

Based near Blaenau Ffestiniog, Gwynedd, Georgina has been surveying large heath butterfly populations across hundreds of square kilometres of peatland habitat since the project began last year.

The study will continue until May 2027 and includes all protected Welsh sites where the species is currently found.

Georgina said: “Peat bogs are weird and wonderful places, with fantastic wildlife like carnivorous plants, large heath butterflies and emperor moths, but looking after them well will also help us tackle the global challenge of climate change by keeping carbon in the ground.

“If we can show that large heath is a reliable indicator of peat bog health then we can be confident that our volunteers don’t need to be technical experts to make a big impact.

“Going out to count the butterfly each summer could provide us with invaluable data to monitor the condition of this environment and plan how to protect it.”

Key monitoring locations include:

• Cors Caron, near Tregaron, Ceredigion
• Afon Eden, Gwynedd
• The Berwyn Range, north-east Wales
• Fenn’s, Whixall and Bettisfield Mosses National Nature Reserve, near the Wrexham-Shropshire border

These wetlands are some of the most ecologically important peat bog habitats in Wales.

What Is the Large Heath Butterfly?

The large heath butterfly is a distinctive chestnut-brown butterfly with prominent black spots on its wings. It is found only in wet habitats in northern Britain, Ireland, and a few isolated areas of Wales and central England.

Its survival depends entirely on healthy peatland ecosystems.

Why this species is so vulnerable:

• Its caterpillars feed on just one plant: hare’s-tail cottongrass
• That plant only grows in peat bogs
• It needs wet, undisturbed habitats to complete its life cycle

Because of habitat destruction and peatland degradation, large heath butterfly numbers have fallen dramatically in England and Wales over the last century. The species is now officially listed as endangered.

How Butterflies Could Reveal Whether Peatland Restoration Is Working

The goal of the project is to discover whether the presence — and abundance — of large heath butterflies can be used to measure the success of peatland restoration projects.

Georgina is particularly focused on identifying whether restored peat bogs are creating better conditions for:

• hare’s-tail cottongrass
• butterfly breeding
• overall wetland biodiversity

If successful, the research could provide valuable evidence to help landowners, conservation organisations and policymakers better manage and restore peatland habitats.

Volunteers and Drones Supporting Butterfly Conservation

As part of the project, volunteers are being trained to carry out weekly butterfly monitoring walks along fixed routes, helping collect long-term population data.

The study is also testing the use of drone technology to:

• map peat bog habitats more efficiently
• identify important plant species
• monitor restoration progress at scale

This combination of citizen science, traditional fieldwork and new technology could improve how conservationists assess peatland recovery in the future.

Who Is Supporting the Project?

The Welsh Government has awarded £249,000 to support the research, with additional funding from National Lottery sources.

The project also involves several major conservation partners, including:

• Butterfly Conservation
• RSPB
• National Trust
• Natural Resources Wales (NRW)

Although many of the sites are protected, much of the land is still privately owned, which can make large-scale conservation work more complex.

Georgina said: “We’ve got huge blanks on the map – for some of these sites we haven’t had records for 25 years. If we get glorious summer weather and I can go out and visit sites five days a week then I will.”

What Is Peatland Restoration?

Peatland restoration is the process of repairing damaged peat bogs and returning them to a healthy, waterlogged state.

In Wales, peatlands cover around 4% of the country’s land area — approximately 90,000 hectares — but many have been drained, damaged or degraded over time.

Restoration typically involves:

• blocking drainage channels
• rewetting dry peat
• encouraging native bog plants to return
• restoring natural water levels

Once restored, peatlands can begin to function naturally again, storing carbon and supporting rare wildlife.

Natural Resources Wales (NRW) delivered a National Peatland Action Programme which met its targets in 2025.

Why Restoring Peat Bogs Benefits Wildlife, Water and People

Healthy peatlands offer far more than carbon storage.

Restored peat bogs can help:

• lock away carbon
• support rare plants and endangered species
• improve water quality
• protect drinking water supplies
• reduce flood risk
• strengthen the health of river catchments

Because many peat bogs sit at the tops of river systems, they play a major role in how water moves through the landscape.

This means peatland restoration is not just good for butterflies — it is also a cost-effective solution for climate resilience, flood prevention and ecosystem recovery.

A Small Butterfly with a Big Role in Climate Research

The large heath butterfly may be small, but it could become one of the most important species in understanding the health of Welsh peatlands.

As climate pressures increase and peatland restoration accelerates, this endangered butterfly could help reveal whether conservation efforts are truly working — offering hope for both wildlife and the climate.

At Natural World Fund, we recognise that protecting peatlands and the species that depend on them is essential in the fight against climate change and biodiversity loss. Restoring damaged bogs, supporting endangered wildlife such as the large heath butterfly, and safeguarding these vital wetland habitats can help lock away carbon, reduce flood risk, and create a healthier natural world for future generations.

If you care about restoring native wildlife in the UK, support the work of Natural World Fund today.