Marsh harriers, lapwings, and water voles are among the species now using a newly created wetland in Cambridgeshire, offering the first tangible signs that England’s Great Fen restoration project is working. The 9,000-acre scheme, led by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire in partnership with Natural England, has spent more than a year converting drained arable fields into shallow lagoons, reedbeds, and wet grassland. As of spring 2026, observers report that birds, invertebrates, and small mammals are colonizing habitat that was bare farmland just months ago.
From plowed fields to open water
The Great Fen sits between Huntingdon and Peterborough in a landscape that was once one of the largest wetlands in northern Europe. Centuries of drainage turned the region into some of England’s most productive farmland, but at a steep ecological cost: more than 99 percent of the original fenland habitat disappeared, and the exposed peat soils began shrinking and releasing stored carbon.
The restoration project, first conceived in the early 2000s, aims to reconnect and buffer two existing nature reserves, Holme Fen and Woodwalton Fen, by rewetting the farmland between them. That work has involved purchasing land from willing sellers, re-engineering drainage ditches to raise water levels, and sculpting shallow scrapes and pools designed to attract wading birds and aquatic invertebrates. A 2023 Guardian report described the effort as notable for its unusual scale in a region where most nature reserves cover only a few hundred acres.
The most recent phase of construction, completed over the past year, opened several new wetland compartments to water for the first time. Within weeks, standing water attracted diving beetles and dragonfly larvae. Reeds and sedges began establishing along the margins, and bird surveyors recorded lapwings displaying over the wet grassland and marsh harriers hunting across the reedbeds.
Why early colonization matters
Speed of arrival is a meaningful indicator for restoration ecologists. When mobile species like wading birds and raptors move into a new site quickly, it suggests the habitat design is producing the right combination of water depth, vegetation structure, and prey availability. For the Great Fen team, the early wildlife response validates years of hydrological modeling and earthworks.
The presence of water voles is particularly significant. Once widespread across British waterways, the species has declined by roughly 90 percent since the 1970s, largely because of habitat loss and predation by American mink. Restored fenland with dense bankside vegetation offers exactly the cover and food sources water voles need, and their appearance at the Great Fen suggests the site is already functioning as viable habitat for one of the country’s most threatened mammals.
Still, conservationists caution against reading too much into initial sightings. Colonization is not the same as establishment. Birds and mammals will investigate any new water body, but whether they breed successfully and return year after year depends on factors that take multiple seasons to assess: food-web stability, predator pressure, and whether water levels hold through dry summers.
Open questions about water and climate
The biggest long-term uncertainty is hydrology. Eastern England is one of the driest parts of the country, and climate projections indicate that summers will become hotter and drier in the decades ahead. Whether the Great Fen can maintain adequate water levels through prolonged dry spells will determine whether its wetland habitats persist or degrade into dry grassland.
The project’s managers have designed the site to capture winter rainfall and hold it in a network of shallow reservoirs and controlled ditches, but no public hydrological monitoring data have been released to show how the system performs under stress. Peat soils add another layer of complexity: if water levels drop too far, exposed peat oxidizes and releases carbon dioxide, undermining both the biodiversity and climate goals of the restoration.
Carbon sequestration is frequently cited as a co-benefit of peatland rewetting, and the science is well established in principle. Waterlogged peat locks carbon away; drained peat emits it. But degraded peat that has been farmed for generations can take years to stabilize after rewetting, and some sites continue to emit greenhouse gases during the transition. The Great Fen has not yet published site-specific carbon flux measurements, so its contribution to climate mitigation remains a reasonable expectation rather than a documented outcome.
Farming neighbors and local stakes
Turning thousands of acres of productive farmland into managed wetland does not happen without friction. In previous years, some farmers adjacent to the Great Fen raised concerns that higher water levels on the reserve could back up into their own drainage systems, threatening crop yields on neighboring fields. The Wildlife Trust has said it works closely with the Internal Drainage Board and local landowners to manage boundary water levels, but detailed agreements have not been made public.
The project also raises broader questions about land use in a region where farming is deeply embedded in local identity and the rural economy. Restoration can generate new jobs in land management, ecological monitoring, and nature tourism, but those benefits are diffuse and take time to materialize. Whether communities around the Great Fen feel they have a genuine stake in the project’s success, or view it as an imposition by outside conservation bodies, will shape its long-term viability.
Markers to watch as the Great Fen matures
The Great Fen is now entering the phase where early promise either hardens into measurable ecological recovery or stalls. Several markers will tell the story over the next two to three years:
- Breeding surveys: Standardized bird and mammal counts across multiple seasons will show whether the species arriving now are nesting and reproducing, not just passing through.
- Hydrological resilience: Published water-level data through at least one full summer drought cycle will reveal whether the site’s engineering can withstand the region’s dry climate.
- Carbon monitoring: Peer-reviewed greenhouse gas flux measurements from the restored peat will clarify whether the site is a net carbon sink or still transitioning.
- Community engagement: Independent surveys of local residents and farmers will indicate whether the project has built durable social support or faces growing opposition.
For now, the physical transformation is undeniable. Thousands of acres that were plowed and drained a few years ago now hold open water, waving reedbeds, and the calls of returning birds. The Great Fen is not yet a proven model for large-scale nature recovery in lowland England, but it is the closest thing the country has to a live experiment at this scale, and the early results are giving conservationists reason to pay close attention.
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*This article was researched with the help of AI, with human editors creating the final content.
