River wildlife at risk, report warns

WILDLIFE on two of East Anglia's most important estuaries is being disturbed by leisure activities, conservationists are warning.

David Green

WILDLIFE on two of East Anglia's most important estuaries is being disturbed by leisure activities, conservationists are warning.

The Stour and Orwell estuaries provide feeding habitat for many thousands of over-wintering birds and are designated under European law as forming a Special Protection Area (SPA).

Bird numbers have been in decline and increasing recreational activity along the estuaries and their margins, including yachting, dog walking and bait digging, has been concerning conservationists for some time.

New research commissioned by the Suffolk Coast and Heaths AONB Unit and revealed yesterday at the Stour and Orwell Estuaries Management Forum confirms that birds are being significantly disturbed, especially on the Orwell.

However, while the most frequent disturbances are caused by boats and dog walkers, the research suggests it is the more unusual events - such as gunshots and low-flying aircraft - which disturb the greatest number of birds.

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The research took place over three winters between 2004-2007 and was carried out by volunteers, co-ordinated by the Suffolk Wildlife Trust. More than 500 hours of observation was recorded in 15 zones.

The findings will help in the formulation of future management plans for the two estuaries, including some action to mitigate the disturbance impact, but are unlikely to result in any restrictions being applied.

Research findings include:

boating and dog-walking were the most frequent activities within the SPA. These also caused most of the disturbance recorded but birds were most sensitive to relatively infrequent events such as gunshots, low-flying aircraft and bait diggers. These activities displaced greater numbers of birds.

events on the shore caused most disturbance at high tide

birds appeared to tolerate “benign” events such as sailing boats passing by and horse-riders on the foreshore but fewer birds occurred where the number of activities was greatest, especially at high tide.

the greatest disturbance occurred on mudflats on the Orwell that were favoured feeding areas for birds but where visitor levels were high. Hidden approaches, relatively small mudflats and access to the shore at low tide compounded these effects.

Bill Parker, Suffolk Estuaries Officer and acting manager of the Suffolk Coast and Heaths AONB Unit, said: “Meeting the needs of people while protecting the wildlife and tranquil character of the Stour and Orwell Estuaries is one of the most important challenges we currently face. The research that we are unveiling gives us a greater insight into the problem of disturbance, and is a valuable aid in developing strategies to address these often difficult issues.”

Chris Durdin, RSPB spokesman in East Anglia, said: “Disturbance is only one element potentially influencing the number of waders. Others include wider population trends, food supply, damage to mudflats from bait-digging and changes on the estuaries due to rising sea levels, coastal erosion and dredging.”