From the floodplain meadows of the Severn and Avon Vales in the UK to the vast seasonally inundated wetlands of the Lower Mekong valley, across the world, wet grasslands provide places for birds to breed, nest, feed and shelter.
As the sun beats down, a rare marsh fritillary flits between the purple flower heads of devil’s bit scabious while painted ladies and bumblebees feed on knapweed and marsh thistles. A wisp of a breeze sends ripples through a sea of wild grasses, sending up the scent of sweet vernal grass. Insects scurry among the carpets of wildflowers and purple marsh orchids. While hidden among the long grasses, a pair of curlews raise their young. Along ditches, water voles nibble on grasses and reeds, while above pools of deep green glass dragonflies and damselflies dart between yellow flag irises.
Come winter, the wild grasses are gone, replaced now by waterlogged fields full of overwintering birds feasting on the rich soup of seeds left behind from summer.
Wet grassland is periodically flooded or waterlogged by freshwater. In the UK they’re often managed for grazing like at WWT Slimbridge and WWT Llanelli, as well as for hay meadows. They may also contain seasonal water-filled hollows, permanent ponds and networks of ditches.
Wet grasslands are typically found on low-lying, level land often within river or coastal flood plains. Marshy grasslands can be found in Devon, Cornwall and Wales. Lowland meadows can be found across the south of England.
The UK’s wet grasslands provide excellent habitat for breeding waders, such as lapwings, curlews and black-tailed godwit. These ground-nesting birds and their young feast on the invertebrates that live in the soft damp soils, ditches and ponds. Several bat species, including the Daubenton’s bat can be found foraging here. These temporary wet areas are also important for dragonflies, water voles and amphibians, which in turn attract grass snakes who come to feed on the frogs, toads and newts.
During the summer, wet grasslands are a riot of colour, with the pinks of ragged robin followed later in the year by the yellows of bird’s-foot trefoil intermingled with the reds of great burnet, purple thistles and the creamy whites of pepper saxifrage. Rushes, sedges and wild grasses like fescue, sweet vernal grass and Yorkshire fog add to the meadows’ rich biodiversity and provide valuable pollen and nectar for insect pollinators including rare bumblebees.
In the past, some floodplain meadows were deliberately flooded at various points in the year in a practice known as ‘floating’ or ‘drowning’. In places the old sluices and channels can still be seen. This involved skilled management and was carried out by professionals known as ‘drowners’, ‘meadmen’ or ‘watermen’. In winter, this helped produce an ‘early bite’ of grass for sheep weeks before other pastures were ready, while in summer it helped increase the hay crop by raising moisture levels in the meadows. Some meadows still contain special stones that mark out the lots that allocated who held common rights to take a hay cut in the summer.
Our flower-rich wet grasslands owe their biodiversity to traditional systems of hay cutting and grazing that go back centuries. The grasses and flowers are allowed to grow and set seed, before hay is cut late in the summer. This annual removal of vegetation allows the more delicate meadow species to flourish.
In the UK, wet grasslands play a valuable role in flood storage, protecting homes and businesses from flooding. They’re also critical for the survival of many species, particularly breeding and over wintering birds.
In Cambodia, like many wetlands around the world, the seasonally flooded grasslands in the Lower Mekong provide protection for the people that live there, during times of crisis. As the pandemic hit, many migrant workers fled the cities and returned to the countryside to seek refuge with their families. Living off the bounty of Cambodia’s wet grasslands offered for many their best chance of staying resilient during the pandemic.
Wet grasslands were once widespread in the UK, particularly in major river floodplains. Now only a small proportion remain and much has declined in wildlife value because of improved drainage, more intensive farming, and fertiliser and herbicide applications.
This, combined with the effects of climate change is proving devastating to our wading birds, like curlew, redshank, snipe and lapwing, as they’re incredibly vulnerable to any changes that might disturb them on their nesting sites.
Breeding curlews favour open, usually damp, grassland for breeding, and the mowing of these fields too early in the season can prove devastating for their breeding success.
And it’s a pattern repeated across the world. In Cambodia, the wet grasslands of the Lower Mekong floodplain are at threat of being destroyed by rapid unsustainable development. The region’s fragile rivers systems are also severely threatened by the development of hydroelectric dams.
In the UK, WWT is focusing efforts on helping breeding curlew and godwit populations, creating networks of bigger, better connected healthy wetlands so wading birds can flourish. We’ve created new habitat at WWT Welney adjacent to the Ouse Washes, where the wet grasslands provide safe godwit breeding areas.
In addition, many of WWT’s reserves are carefully managed to provide just the right type of wet grassland at the right times of year to benefit wildlife. At WWT Llanelli, we flood our wet meadows in the autumn after the hay cut to provide a valuable floating seed soup for our visiting ducks. Later in the year, we carefully manage water levels to mimic the natural flooding of lowland wet grasslands to create the perfect habitat for ground nesting waders. We do the same at WWT Slimbridge to provide a valuable breeding habitat for lapwing and redshank.
Abroad, WWT works in Cambodia in some of the last remaining remnants of seasonally inundated wet grasslands in the Lower Mekong, supporting local communities to manage natural resources in a more sustainable way.
WWT is also backing an Emergency Recovery Plan that sets out the steps needed to halt the catastrophic collapse in the world’s freshwater biodiversity in wet grasslands like those in the Mekong delta.
WWT creates, protects and restores wetlands for wildlife and people, including wet grasslands, at our sites across the UK and internationally. Join and support WWT now to support our work and access all our wetland sites for free.