The impact of yesterday's helicopter crash on the sensitive and internationally-important Norfolk Wildlife Trust Cley Marshes nature reserve would probably only be short term, according to trust chief executive Brendan Joyce.

Mr Joyce said he expected the US Air Force and Ministry of Defence to clear it up when their investigations were complete, and to deal with any damage caused by spilt fuel, oil and other pollutants.

'I am not anticipating any long-term consequences,' he added.

Although a major human tragedy, the accident was nowhere near as environmentally damaging to the reserve as December's storm surge had been, said Mr Joyce.

Breaches caused by the surge along the reserve's shingle bank were repeatedly allowing sea water to flood vital fresh water pools and the trust viewed repairs as a matter of 'extreme urgency'.

The crash had also happened at a time when no birds were breeding, although trust figures for November estimated a reserve population of some 2,500 pink-footed geese, more than 1,000 Brent geese, more than 900 golden plover, nearly 500 lapwing, curlew, plus large numbers of over-wintering species such as teal and widgeon.

Mr Joyce said suggestions that a bird strike could have brought down the helicopter were pure speculation. Low-flying aircraft were likely to send up large numbers of disturbed birds, but they settled again quite quickly.

Cley Visitor Centre, a Mecca for birdwatchers, was being used as a base by military personnel investigating the crash and, together with the reserve, was likely to remain closed to the public until Monday.

This morning Mr Joyce met officials from the Environment Agency and Natural England to discuss the agency's plans for repairing the storm surge breaches.

'The reserve is being continually flooded. Salt water is sitting on fresh-water habitats and the longer that happens, the more long-term damage will result,' he said.

The main breach was at Salthouse but there were lesser ones on National Trust land at Blakeney Freshes, between Cley and Blakeney.

Mr Joyce said the Environment Agency had taken on board the trust's concerns and sense of urgency but had not given a date when the work would be carried out.

Local suggestions that it would only take a bulldozer to shift the shingle back in place were wrong because that solution would be 'futile' and much more robust action was needed.

The Environment Agency had said the work could cost hundreds of thousands of pounds and the trust was mindful that the agency was 'severely up against it', having to deal with problems all over the country, not just the east coast.

However, Mr Joyce said he would be meeting them again within a week or two and, if no date was forthcoming, he would enter 'haranguing and harassing mode'.

Although coastal erosion and rising sea levels would eventually destroy the reserve, the trust, backed by Natural England, believed it was still worth preserving the fresh water habitats for a few more decades.

'From a conservation, tourism and local economy point of view the reserve is very important,' said Mr Joyce.

'It has reed beds, salt marshes, coastal grazing marshes and breeding birds. There is hardly a bird watcher in the country who hasn't cut their teeth at Cley. We get more than 100,000 people a year coming to the visitor centre and that creates quite a lot of direct and spin-off employment.'

The surge also caused severe structural damage to the boardwalks serving the reserve's main block of hides.

Last September the picture was much rosier for the trust when it celebrated the success of its £1m public appeal to help buy 143 acres of Cley Marshes called Pope's Marsh, expanding the reserve by one third. The purchase connects an unbroken eight kilometres of protected sites stretching from Blakeney Point to Salthouse Marshes.

But Mr Joyce said they had been forced to put restoration work on their new land on hold until the breaches had been fixed.

The land purchase is part of a larger, £2.6m project called A Living Coast which aims to create a network of internationally-vital habitats for many endangered species including marsh harrier, avocet, spoonbill, bearded tit and bittern.

The project, supported by a £1.5m grant from the Heritage Lottery Fund, will also see the Simon Aspinall Wildlife Education Centre built, meeting a growing demand for information, education and events.

? Anyone wishing to support the trust's project and/or the cost of repairs and restoration following the storm surge can do so by visiting: www.norfolkwildlifetrust.org.uk or ring 01603 625540.