The dense development of Hong Kong has taken a greater toll on nature than in most other cities. Few are left who would remember an abundance of natural flora and fauna and a thriving biodiversity. Sadly, as man has moved in, nature has moved out. The reverse is true. If man keeps out, nature moves in as it retreats from the barren urban sprawl. Areas spared from development can become sites of unexpected ecological importance. An unusual example is the public no-go area on the Hong Kong side of the New Territories border, a 2,800-hectare buffer strip untouched by development for 50 years. A mixture of farms, wetlands, villages and rugged hills, it was restricted not as an ecological reserve, but as a barrier to illegal immigration. Nowadays, there is not the same need for such a buffer, and a government source has revealed a plan to open up about 2,000 hectares of it for ecotourism and low-density development. This is bound to cause conflict between conservationists, developers and villagers wanting the best value for their land. The plan should be considered with great sensitivity for the area's delicate biodiversity as well as due regard for the interests of residents. A recent study by the Kadoorie Farm and Botanic Garden of parts of the northeast New Territories and the Eastern Frontier Closed Area should be required reading for officials and planners. It identified a number of threatened or rare species in the area's diverse habitats. Many of these habitats only emerged in the 50-odd years since the restricted area was established. They were found to be home to all sorts of plants and animals. The species identified include four rare ferns, the mountain wolf snake, the Malayan porcupine, the yellow-bellied weasel and the crab-eating mongoose. Researchers say Hong Kong risks losing a significant number of valuable species if development is mishandled. They want the government to consider environmental and social uses as well transport links, logistics and residential and other forms of development. It should not be forgotten that most residents did not knowingly move into an environmentally sensitive area. It simply grew up around them as species sought sanctuary from urban development. They are now caught in the middle of efforts to strike a balance between conservation and development as planners struggle to find areas for new housing. It is reassuring that a government source says it is unlikely that any new towns or big developments will be allowed, and sites with high conservation value will be protected. However, the changes are seen as promoting ecotourism, which is not always compatible with conservation. A thorough ecological assessment to minimise the impact of any development on species in the area would be a sensible first step.