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Bogs
Bogs form when standing water, usually rainwater, fills up with dead plants and becomes spongy, wet soil. Since they're always waterlogged, plant material builds up to form peat.
Wetlands
From windswept saltmarshes to ancient peat bogs, the UK's wetlands are among its richest habitats for wildlife. These waterlogged landscapes provide homes for thousands of species while helping to store carbon, and reduce flooding and pollution.
What is a wetland?
Wetlands are areas of land with high water levels and waterlogged soils that can either be permanently wet or flood seasonally. They are dynamic habitats that change with the seasons and can develop into different forms over time.
In some wetlands, dead plants do not fully decompose because the ground is too wet, acidic and low in oxygen. Over thousands of years, this material builds up to form peat.
Peatlands are remarkable ecosystems. They are the world’s largest terrestrial carbon store, locking up more carbon than all other vegetation types in the world combined. They provide important habitats for plants, such as sundew and marsh violet, which in turn support invertebrate and bird populations.
People have long used peat for fuel, and its absorbent properties have also made it useful for cleaning up industrial oil spills.
Types of wetland
There are four main types of wetlands in the UK.
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Marshes
Marshes form near rivers and along coastlines, often at the mouth of the river. The water can be fresh, salty or brackish (a mix of the two). Marshes typically have grasses, reeds and no trees.
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Swamps
Swamps are areas flooded around rivers, ponds or lake margins. They're rich in wildlife because their shallow waters and abundant vegetation provide food, shelter and breeding grounds for many species. Swamps can be freshwater or saltwater, with saltwater swamps typically found along coastlines.
Key features
No two wetlands are exactly alike. Differences in nutrients, water levels and sunlight create the perfect conditions for different plants to thrive. In spring and summer, wetlands can burst into colour with marsh marigold, cuckooflower, orchids and devil's-bit scabious, while common reed, bulrush, white water lily, sphagnum moss and duckweeds shape the habitat year-round. Wetlands, particularly wet woodlands, also provide ideal conditions for trees such as willow, birch and alder.
Wildlife
Wetlands are rich in biodiversity, supporting around 40% of the world’s plant and animal species and providing habitat for more than 30% of all fish species.
A walk through a wetland can reveal an astonishing variety of wildlife. Birdwatchers may spot familiar ducks such as mallards, tufted ducks and shovelers, while kingfishers flash across the water and curlews call overhead. Mute swans, coots and countless other wetland birds rely on these habitats for feeding, nesting and shelter.
Beneath the reeds and along the water’s edge, mammals such as otter and water vole make their homes. Wetlands also support a remarkable diversity of insects. Dragonflies and damselflies patrol the water, while species such as bog bush-cricket and pond skater depend on wetlands for food, breeding and protection from predators.
Healthy wetlands are equally important for fish. Clean, filtered water, abundant aquatic vegetation and the shade provided by surrounding trees create ideal conditions for fish to feed and thrive.
Why are wetlands important?
Wetlands are among the world’s most valuable ecosystems. Not only do they provide vital habitat for wildlife, they also help keep our water clean, reduce flood risk, store carbon and create spaces where people can connect with nature.
Wildlife
Wetlands support an extraordinary diversity of plants and animals. From rare wildflowers and insects to fish, birds and mammals, many species depend on wetlands for food, shelter and breeding grounds.
Clean water
Wetlands act as natural water filters and improve water quality to support healthier ecosystems.
Flood defences
Wetlands act like sponges, absorbing rain, snowmelt and mist before gradually releasing it back into the landscape. This helps slow the water flow and reduces the risk of flooding downstream after storms while maintaining water flow during dry weather.
Carbon storage
Healthy peatlands are powerful carbon sinks. They absorb and lock away more carbon from the atmosphere than they release, helping to tackle climate change. The amount of carbon a wetland can store depends on its condition, making effective management and restoration essential.
People and wellbeing
Wetlands support the livelihoods of millions of people worldwide and provide opportunities for recreation, learning and connecting with nature. Spending time outdoors in nature can benefit both physical and mental wellbeing.
Did you know?
Before Roman times, wetlands covered around 25% of the British Isles. Today, they make up just 5% of the UK landscape.
Threats
Habitat loss
Wetlands are one of the world’s most threatened habitats. In the UK, over 90% of wetlands have been lost in the last 100 years, while globally an estimated 87% have disappeared in the past 300 years. This dramatic decline has been driven by drainage for agriculture, housing and industry, as well as urbanisation and nutrient enrichment.
Pollution
Runoff from fertilisers and pesticides, industrial waste and major pollution incidents can all affect water quality and harm wildlife. Yet wetlands are also part of the solution. Acting as natural filters, they can remove or eliminate pollutants. For example, they have the potential to eliminate up to 90% of nitrogen from water.
Invasive species
Invasive non-native species can spread disease, outcompete native plants and animals for food and space, and reduce biodiversity.
Climate change
Changes in rainfall and temperature can cause them to dry out, affecting the wildlife that depend on them. But much like pollution, wetlands also play a vital role in tackling climate change by acting as carbon sinks. If wetlands are damaged or destroyed, however, that stored carbon can be released back into the atmosphere.
Conservation
Wetlands are nature-based solutions to climate change and pollution, making their protection more important than ever. In the UK, wetlands are protected under the UK Biodiversity Action Plan which aims to protect and enhance habitats for endangered species.Despite these protections, many wetlands remain in poor condition.
The good news is that wetlands can recover remarkably quickly. When restored, wetlands can often be rapidly recolonised by plants and animals, bringing these ecosystems back to life.
Conservation efforts focus on protecting existing wetlands and restoring those that have been damaged. Measures such as restoring rivers, reducing drainage and abstraction (removal of water) can help wetlands thrive for the benefit of wildlife, the climate and people.