Wildlife/Conservation

Look at an outline map of Britain and the huge indentation of the Wash is one of the most recognisable parts of this country’s coastline. Probably not so well known is the history and geography of this unique area, dismissed by some as flat and featureless. This curious landscape repays closer inspection, birdwatchers will already know that this is the place to see important numbers of wildfowl and waders but perhaps less is known of the dramatic way in which the coastline has changed over the centuries. Through the Boston Wash Banks project it is still changing - managed realignment may not sound very inspiring but read on to find out more, for this is a truly innovative and exciting project and one which visitors are encouraged to see the work as it progresses.

The Wash is a huge intertidal estuary into which the Rivers Witham, Welland, Nene and Ouse all flow. It consists of a complex mosaic of inter-dependent habitats, which together form a highly productive ecosystem. The vast mud flats, saltmarshes and saline lagoons make it one of Britain’s most important winter feeding areas for a wide variety of migrating birds.

The Wash holds 10% of Britain’s saltmarsh, an increasingly rare habitat. The plants and animals that live here have adapted to cope with regular salt water flooding under high tides. Frampton and Kirton saltmarshes support a globally important population of wintering dark-bellied brent geese and one of the highest densities of breeding redshanks in the UK. Large numbers of waders and wildfowl use saltmarshes for roosting and feeding in winter including shelducks, wigeons, teals, oystercatchers and curlews. Important numbers of twites, which breed in upland areas, depend on these saltmarshes in winter.

Also reliant on saltmarsh are a rare ground beetle, the scarce pug moth and a grasshopper, the wonderfully named short-winged conehead. The marshes are a purple haze in summer with sea lavender and sea aster, with samphire being traditionally collected for food.

Saline lagoons are one of this country’s rarest coastal features and as part of the Boston Wash Banks project a new lagoon has been created at Freiston Shore RSPB nature reserve. Scarce invertebrates such as the lagoon sand shrimp and lagoon prawn all depend upon this element of the coastal environment. Two species of spire snail, a hoverfly and the tentacled lagoon worm also thrive. Brackish water crowfoot, spiral and beaked tasselweeds and saltmarsh goosefoot are just a few of the plants associated with it. This will also prove an important new habitat for birds such as avocets and lapwings.

Intertidal mudflats cover about 40% of the Wash and are the second largest area of this habitat type in Britain. The fine sediments support abundant communities of invertebrate species such as lugworm, cockles, Baltic tellins, mussels, mud-snails and ragworms which feed in the nutrient rich mud. These invertebrates in turn support some 23 species of duck, geese and waders both native and migratory. In addition the estuarine sandbanks support the largest group of common seals in Europe.

The sea level is presently rising around the south east coast of Britain because of a combination of natural vertical land movements and global warming. This sea level rise and increased storminess will affect all coastal land types. Normally as sea level rises the saltmarsh would move inland. However, they are prevented from doing so by the artificial sea banks. The resultant coastal squeeze has led to an alarming loss of intertidal habitats and it is now increasingly realised these habitats provide ‘soft’ but very effective natural defences. A healthy saltmarsh fronting a seabank forms an integral part of the flood defence as it dissipates the power of the waves as they move up the marsh. As well as fulfilling a flood defence role it will also help wildlife such as breeding redshanks and wintering twites.

This whole process known as managed realignment, it is, so far, the biggest example of such a project in the UK. The work is ongoing and visitors will be able and are encouraged to see how the work progresses as new habitat develops. Some may be concerned that land is being given up to the sea, but it is just 78 hectares, compared with the 47,000 hectares of farmland which have been claimed from the sea since Saxon times. This recreation of saltmarsh replaces just slightly less than the 100 hectares of saltmarsh lost every year in the UK.

An outstanding example of environmental innovation and good practice, the Boston Wash Banks project is one of the most exciting flood defence programmes Britain has seen for over a century. Working with nature is proving the more successful way forward - for birds as well as people.