NEAR WHERE I STAND, deep inside the Mai Po Nature Reserve, a little white egret bursts into flight from its roost in the mangrove. It shatters the silence and my musings on the fate of this threatened wetland. The bird makes its frantic ascent and I cannot help but see it as a symbolic retreat of nature in the face of the relentless push by humans to reclaim, develop and make money from every scrap of land available. I have come to the 1,500-hectare reserve in the northwestern New Territories in search of a better understanding, if not definitive answers, of the future of mud flats and mangroves in Hong Kong and elsewhere. I had pinned my hopes on Mai Po's nature reserve manager Dr Lew Young, to take me on a walk not only through the park, but through the issues that face environmentalists everywhere in promoting the conservation of what the ordinary sceptic may see as marginal land. In the case of Mai Po, there is also a question of scale, since the park is roughly the same size as Chek Lap Kok. If anyone has the answers, it should be Dr Young, an ecologist who has worked at Mai Po for a decade. The turnoff to the wetland is near Fairview Park, after a journey on the noisy, crowded San Tin Highway. You could not miss the fact that the wetland is a hot issue locally. At the road junction leading to the conservation area are banners blaming green groups for delaying a drainage project which villagers said could ease flooding threats. Dr Young, dressed in a green shirt and shorts, and smiling broadly, extends a friendly handshake before apologising for being too busy to talk for a while. I will have to form my own impressions to start with. We arrange to rendezvous an hour later to visit the gei wai, the traditional shrimp farms. Meanwhile, the photographer and I explore the reserve's famous floating walkway. As I walked along, it somehow hit me more forcibly how remarkable it is that the area has escaped development despite all the building around it. It was amazing, too, to see the abundance of wildlife in the mangroves, mud and waters bordering Shenzhen, which is visible across Deep Bay. At its height in 1997, the reserve's bird population was 60,000, including blackfaced spoonbills and 12 other endangered species. There are also about 400 species of insects in the reed beds and mangroves. Using the government's valuation measures for arable land, the reserve is worth about $4.5 billion, without development. The huge area clearly represents an opportunity from the perspective of developers. It might have helped ease congestion in the overcrowded urban area while bringing in revenue from the land sales. It is while I am reflecting on this dilemma that the egret makes its break into the sky. By now it was also time to rejoin Dr Young to seek his point of view and to visit the old shrimp beds, which are now dredged to boost the process of flushing salt water through the swamplands. He is frank with his answers. He is less worried now than he ever has been about the encroachment of housing development. He is far more concerned about excessive sedimentation and the possible drying up of the wetland. 'What we have been doing is just delaying the process of degradation and extending the lifespan of Mai Po,' he said, referring to dredging of the gei wai. 'Perhaps in 100 years time, the site will still be there, or maybe not.' It seems the keepers of the reserve are in a no-win situation, since the dredged sediment is heaped along the banks of the gei wei, which has raised the height of the mud flat. If the mud flat rises above the tide level, the wetlands will dry up. At the moment, the environmentalists have no solution to the problem. At least part of the reason Mai Po has survived this long is because attitudes both within the community and on the part of the environmentalists have changed over time. Dr Young, for instance, was once militantly in favour of keeping people out of the park to create a more pristine environment for its bird population. Now he has relented. Developers have even started to use the reserve as a promotional tool, according to Dr Young, to entice buyers who want to live near greenery and open space. Dr Young is still wary, however. 'The danger is still there,' he said. Developers have managed to convince the government to let them encroach upon the conservation area by agreeing to maintain the fishponds and mud flats in their original condition, using only small parts of the area for flat construction. This could be looked at either as gradual attrition of the wetland or as a way of moving people as close as possible to its natural beauty while tapping rich developers to pay part of the cost of maintaining the wetland. The pioneer is Cheung Kong's development in Fung Lok Wai, beside the fishponds. Cheung Kong has pledged to keep them intact to attract birds. Mai Po was listed as a conservation area in 1975, just after nearby Fairview Park, the New Territories' first low-rise private housing project, was completed. Three years later, Yuen Long, about three kilometres away, was designated as a new town site. Two years after that, Shenzhen became the first special economic zone, starting a process of development that would turn a sleepy town into one of southern China's major centres. On the mainland side, the Futian nature reserve has been partially reclaimed for road and residential use. In 1995, Mai Po was listed as a wetland of international significance in recognition of its importance for birds following migration paths from as far away as Siberia and Australia. Dr Young is often asked why Mai Po should be maintained when there are many such reserves on the mainland and elsewhere in Asia. 'Just because there is a park in Shanghai, does it mean that we should forget or lose our own park?' he replied. The ecological value of the world's wetlands is huge, not just for sustaining migratory bird life but for purifying water and flood control. Global wetlands are calculated to be worth US$30 trillion (HK$234 trillion) in terms of the economic functions they perform. Some people might not like the idea of putting a price on nature. But I like to believe that nature is worth something, and if we lose Mai Po, we are throwing away enormous value. Cheung Chi-fai is a Post journalist Graphc: MAI05GET