Over recent decades, large swathes of Slovakia’s wetlands have been lost. They have been drained to make way for agriculture as a result of the construction of dams for hydroelectric power, as well as for timber production. Wetlands are an integral part of the Danube floodplain landscape in Slovakia and draining them to plant trees has detrimental impacts on the environment. Wetlands store large amounts of carbon and are home to a diversity of plant and animal species that are specially adapted to the wet conditions. One of these species is the nationally endangered and endemic Pannonian root vole, which has declined drastically in Slovakia in response to disappearing wetlands. This project will turn forest back into a wetland by digging 650 meters of ditches. This will kickstart a “flood” of change and bring back a healthy functioning, sustainable and wilder ecosystem.

Two years ago we flooded a forest- now it's full of life

Excavated 650m of water channels to flood 60ha of lowland wetlands and floodplain forests.

Spring simulated flooding regime initiated by increased water flows from the dam water management company. In May the forest began to flood.

Spring simulated flooding regime records the highest levels of water enter the forest in 30 years.

Summer simulated flooding regime conducted by the dam water management company. This was to predominantly to clean the river branches of mud and silt, resulting in a reduced amount of water entering the forest.

Ongoing annual simulated floods and monitoring of the improvement to Pannonian root vole habitats (carried out by Comenius University Faculty of Natural Sciences). Additionally, regular monitoring of areas affected by floods will be conducted using GPS and drone mapping.

10.7 ha of land bought for wetland protection.

Monitoring results show encouraging progress in our restoration area. Invasive plant species are retreating, while native wetland plants are expanding in these rare habitats.

This ambitious project aims to restore an area of degraded wetland by digging water channels that to reconnect the site to a nearby river. These channels will enable water to travel from the river to the core area of the wetland and restore a more beneficial flooding regime. The project will also remove encroaching woody vegetation that is outcompeting the native wetland plant communities. 

create suitable conditions for the regeneration of the wetland plant communities;

suppress the expansion of non-native plant species;

create suitable habitat for a diversity of invertebrates, amphibians, birds and mammals;

and finally, sequester vast amounts of carbon.

We will be supporting our partners BROZ to create 650 meters of water channels to restore a 64ha wetland. 

Learn More About the Context Behind this Project

Wetlands can be found anywhere water interacts with land. The diverse and complex conditions of wetland habitats can support a diversity species, including an abundance of invertebrate and bird life. Wetlands are therefore some of the most biodiverse ecosystems on earth. They also play a crucial role when it comes to climate change. They help fight floods by absorbing excess water and limit droughts by releasing water slowly.

The waterlogged conditions combined with high plant productivity make many freshwater wetlands, including the wetlands we are restoring, significant carbon sinks. Our wetland has the potential to sequester between 200 – 350 tonnes of carbon per year (Mitsch et al., 2013; Brix et al. 2001). When converted to carbon dioxide this means that every year it will sequester about 1290 tonnes of CO2 out of the atmosphere. That is the equivalent of you taking 3902 flights between Lisbon and London or the full footprint of about 189 average Europeans each year. 

The Pannonian root vole is what’s known as a glacial relict. This means it is a species leftover from the cold-adapted communities of the Ice Age. As the climate warmed and the continental ice sheets retreated, the Pannonian root vole population disappeared from most of its range.  However, it managed to avoid complete extinction, surviving as isolated populations in the vicinity of the Danube river in Slovakia, Hungary and Austria. 

Despite clinging on for thousands of years after the Ice Age, the Pannonian root vole is now under immense pressure from human activity. As well as having an already restricted range, the Pannonian root vole has very specific habitat requirements, which makes it a particularly sensitive species. 

Their survival hinges upon the conservation and restoration of functioning wetland habitats. 

The site we are restoring was drained during the 80s and 90s primarily due to the construction of a dam, and secondarily to create suitable conditions for timber production. An extensive wetland ecosystem, 80ha in size, was lost. This is a perfect example of how not all tree planting is beneficial to the environment. 

Prior to this project, the site had still flooded, but very rarely and for such a short period of time that the wetland’s natural communities were unable to establish. The native plant species that are important for the Pannonian root vole had been in a state of decline and had been replaced by woody vegetation, such as shrubs and trees, and invasive plants had taken over. Our intervention has begun to reverse this situation. See the transformative results in the videos below.

See the impressive results of the first flood below!

We flooded a forest - the result blew our minds

What Happened to the Forest We Flooded?

Showing the results of this year's spring & summer floods.

One year ago we flooded a forest - the results are insane

Hannah Kirkland, Conservation Biologist at Mossy Earth

Adriana Brossmannova, Conservation Biologist at Mossy Earth

Returning a regular flooding regime to create a temporary wetland habitat. 

Mossy Earth Final Report and Spending Report.docx.pdf

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Microtus II Wetland Restoration Management Plan.docx.pdf

Flooding a forest to restore a wetland ecosystem in the Slovakian inland delta of the Danube River.

Restoring Wetlands

Turning a forest back into a biodiverse, carbon rich wetland

Recent monitoring shows encouraging progress in our restoration area. Invasive plant species are retreating, while native wetland plants are expanding in these rare habitats.

Our Flooded Forest restoration area is not only forest. It also includes wet sedge meadows—an important habitat for the Pannonian root vole, a small endemic mammal. This species is considered an umbrella species, meaning that protecting its habitat also protects many other species that depend on the same conditions.

The Pannonian root vole lives almost exclusively in wet meadows dominated by tall sedges such as Carex riparia, which form a key part of its diet. Healthy sedge meadows require constant soil moisture or shallow groundwater and minimal disturbance or drainage. When these conditions disappear, the vole—and many other wetland species—disappear as well.

Before the Danube River was regulated and large areas of the Pannonian Plain were drained, wet sedge meadows were common across the Danube lowlands. Today they are increasingly rare.

Even within the Danube floodplains, the waterlogged conditions needed for sedges often no longer occur. When these wetlands dry out, native plant communities are quickly replaced by non-native invasive species.

The positive news is that when water returns, native wetland species can recover quickly.

This recovery is already visible in our Flooded Forest restoration project. Efforts to control invasive plants—particularly Solidago gigantea and Symphyotrichum lanceolatum (formerly Aster lanceolatus agg.)—began in 2020. Our partner organisation BROZ started by cutting and mulching the invasive plants. In 2022, water was reintroduced to the area as part of the restoration project.

Since then, BROZ has continued annual mowing and mulching to support the return of native species such as Chaerophyllum bulbosum, Galium aparine, Humulus lupulus, and Carex riparia.

At the start of the project, four monitoring plots were established to track changes in the plant community.

In one plot, invasive species covered nearly 100% of the area in 2020. By 2025, their cover had dropped to 20%, while Chaerophyllum bulbosum expanded to 60% coverage.

In the other three plots, Solidago gigantea has strongly declined or nearly disappeared. At the same time, the diversity and coverage of native plants have increased.

However, monitoring also revealed a new challenge. In two plots, the non-native Symphyotrichum lanceolatum has begun to occupy space left after the reduction of Solidago gigantea.

Mulching appears to be an effective short-term method for controlling Solidago gigantea. Its effectiveness against Symphyotrichum lanceolatum, however, remains uncertain.

Based on experience from other sites, livestock grazing may prove to be a more effective long-term strategy for suppressing this species and supporting the recovery of native wetland vegetation. BROZ is currently exploring the feasibility of bringing livestock into the area.

Monitoring shows invasive plant species retreating and the cover of native species expanding at rare wetland habitats.

Flooded Forest

More Than a Forest

A Rare Habitat

Restoration in Action

What Monitoring Shows

Next Steps