More than a third of Britain’s most ecologically valuable lakes need rehabilitating after years of exploitation and degradation, according to an Environment Agency-led study released for World Wetlands Day (February 2).

Of the 1047 British lowland lakes1 that are classified as either Sites of Special Scientific Interest (SSSI) or support vulnerable Biodiversity Action Plan (BAP) species, 379 are degraded and in need of rehabilitation.
 
“Lakes such as Windermere, Bassenthwaite and Esthwaite are large bodies of water that can dominate the landscape, places for recreation, and for many of us, the source of our water supply,” said Environment Agency ecologist Geoff Phillips.

“But we still take them for granted. Many lakes in the UK are severely stressed and their ecology shows signs of change. These changes are the result of human induced pressures, to an extent inevitable, on a densely populated island.”

Britain2 has a total of 14,000 lakes1, of which 7679 are classified as being either mesotrophic or eutrophic. Both types of lakes are usually found in lowland areas, but eutrophic lakes have a much higher nutrient content, encouraging the rapid growth of aquatic plants. Unfortunately some of the (lower nutrient) mesotrophic lakes have been artificially enriched with nutrients and now exhibit the eutrophic condition.

“The most widespread pressure on lakes is that resulting from the enrichment of their water by nutrients, nitrogen and phosphorus. In their natural state, lakes have relatively low nutrient concentrations, but since the middle of the 20th century many have received additional nutrients from agricultural land-use and input of treated sewage. This has had significant impacts on the biodiversity they contain and there is clearly a need to reverse this process.”

Examples of change as the result of human induced pressure, include:
• blue green algal scum which builds up along a shore line during a hot summer;
• direct impact on fish populations, for example Arctic Charr in Lake Windermere and the rare Vendace in Lake Bassenthwaite;
• the complete loss of submerged aquatic vegetation in the Norfolk Broads, leading to reduced diversity of aquatic invertebrates, and changes to the age structure and composition of fish. 

As a result of this classification study – carried out by UK Lakes Habitat Action Plan (UK Lake HAP) Joint Steering Group (www.lakeshap.org.uk/ ) – the most ecologically valuable but degraded lakes have been identified for rehabilitation.

“The broad intention of the Lake Habitat Action Plans, is to ensure that management actions are taken to improve the condition of our lakes. This means protecting those lakes which are currently in good condition, improving the most important of those that have deteriorated and ensuring no further decline occurs to the overall status of lakes,” Phillips said.

The Bassenthwaite Lake Restoration Programme (BLRP) will serve as a benchmark in lake rehabilitation for the UK Lakes HAP Steering Committee. With £2.8 million in funding – including newly announced Heritage Lottery funds of £1.8 million – a swathe of community driven volunteer projects are being carried out to rehabilitate the lake and catchment.

“The BLRP is already using a catchment wide strategy consistent with the UK Lake HAP approach to restore ecological quality, while also targeting the cause of the eutrophication by working with agriculture, forestry and tourism industries to cut down on nutrient input into the lakes.”

The UK Lakes Steering Group divided the United Kingdom’s 14,000 lakes across a spectrum ranging from the least to the most fertile:

• Oligotrophic lakes – have naturally very low nutrient levels and are usually found on old hard rocks in upland areas. Support only very limited biological production. Much less degradation due to their upland location.
• Mesotrophic lakes – have naturally low nutrient levels and are usually found on slightly softer, easily eroded rocks. Support a wide range of plants and animals and contain many nationally scarce or rare plants and animals (many are still in good condition but some have elevated nutrients and in this condition become unnatural “eutrophic” lakes).
• Eutrophic lakes – naturally high nutrient levels, typified by hard calcareous water and usually found in lowland areas. Support prolific and often diverse aquatic plants.

The Environment Agency showed why it is well placed to take a leading role in the restoration of UK wetlands by scooping the prestigious Living Wetlands Award, announced today. Run jointly by the RSPB and the Chartered Institution of Water and Environment Management (CIWEM), the award recognised the work done at Sutcliffe Park in Greenwich to transform a once featureless playing field into a wetland haven for wildlife.

After decades of having the River Quaggy reduced to a subterranean culvert, the rehabilitation of the park incorporates flood mitigation measures including a new lake, with the reappearance of the Quaggy’s meandering waters. The park now attracts an array of birds and insects, including grey heron, jack snipe, wagtails and large numbers of dragonflies.

The UK Lakes Habitat Action Plan (UK Lake HAP) Joint Steering Group includes: Countryside Council for Wales, Environment Agency, Environment and Heritage Service (Northern Ireland), Joint Nature Conservation Committee, Natural England, Pond Conservation Trust, Scottish Environmental Protection Agency and Scottish Natural Heritage.

Environment Agency ecologist Geoff Phillips will be addressing the CIWEM World Wetlands Day Conference 2007 – Developing Practice on the Ground – on 31st January 2007 in London.