The government's blueprint for the closed border area includes a zone that preserves natural and heritage treasures, balanced by low-density residential development. But the lack of provisional development controls may easily tear the beautiful vision to pieces, environmentalists say. Green groups worry that agricultural land and ponds in the area will be covered up to make way for development or be used for open storage after the area is released. A village representative also said the absence of economic incentives would make it hard for the villagers to retain their heritage buildings purely for preservation's sake. Alan Leung Sze-lun, of WWF Hong Kong, welcomed the government's proposal to protect sites with high ecological value and scientific interest, such as the Ho Sheung Heung egretry and Lin Ma Hang stream. The egretry is one of Hong Kong's largest colonies of the waterbirds, while the Lin Ma Hang area is home to many forest birds and rare animals. But Mr Leung said the fate of the farmland and ponds was solely in the hands of their owners without laws to prevent disturbance of the sites. 'It is not hard to imagine that the landscape of some agricultural land and ponds will be disturbed, just like the ones in the New Territories, if there is no regulation,' he said. Cheung Tin-sung, representative of San Uk Ling village in Ta Kwu Ling, said the 'incentives' in the government proposal could be empty words as there were no details on how preservation would appeal to villagers economically.