Shenzhen's plan to convert wetlands on the shores of Deep Bay, off northwestern Hong Kong, into a commercial zone with soaring skyscrapers will pose a major threat to bird migration patterns, environmental experts and groups say.
The city government's project on what mainlanders call Shenzhen Bay was launched in September. A planning design contest to build a "super city" in the area began in June, drawing 124 entries from around the world.
A jury will select eight designs, with the winner getting two million yuan (HK$2.5 million) and the runner-up 800,000 yuan.
The plan calls for a cluster of business headquarters to be built in the Qiaocheng wetlands in Nanshan district, upstream from the Mai Po marshes in Hong Kong. A 35.2-hectare area will be converted into a dense urban centre, according to a blueprint posted on the website of the city's Urban Planning Land and Resources Commission.
Officials hope to develop a bay area economy that may eventually be on par with the San Francisco Bay Area.
Several skyscrapers of 150 to 680 metres tall will line the shore of the bay. Underground transport links and overhead pathways will connect the towers, which are expected to cater for 180,000 to 220,000 workers.
Four environmental groups based in Hong Kong - WWF, Green Sense, the Hong Kong Bird Watching Society and the Cross-border Environment Concern Association - said they knew little of the development plan, but were very concerned that a commercial project so close to Deep Bay would threaten the many migratory birds visiting the Mai Po Nature Reserve each autumn, winter and spring.
Hong Kong's Environmental Protection Department and Agriculture, Fisheries and Conservation Department did not return calls seeking comment, nor did Shenzhen's urban planning commission.
Dr Wen Xianji - a mangrove specialist for WWF, which manages the nature reserve - said the organisation did not know if the Hong Kong government had been informed about the plan.
But any change on the Shenzhen side would affect the environment in Deep Bay, he said.
"Deep Bay is one of the most important stopover sites for migratory bird species that traverse the East Asian-Australasian Flyway," Wen said. "Mai Po and Shenzhen's wetlands in Nanshan and Futian districts have a critical influence on bird migration patterns in East Asia."
He said the planned skyscrapers on the migratory route would definitely affect shorebirds and the Mai Po reserve.
"The buildings will become a physical barrier to the shorebirds and stop them from flying freely between Hong Kong and Shenzhen," he said. The ecological value of the reserve and Shenzhen's wetlands would also be badly damaged, he added.
Yu Yat-tung, research manager of the Bird Watching Society, said: "The wetlands area at Deep Bay is one of the most important in the world, but because of cross-border jurisdictions, it has been treated in two separate ways … Hong Kong authorities cannot plan or manage wetlands on the Shenzhen side, and vice versa. We have heard nothing about the giant commercial project in Shenzhen.
"Such a cluster of skyscrapers would definitely be a deathtrap for the birds. You would [see] flocks circling in confusion around skyscrapers and repeatedly colliding with windows and building signage."
Johnny Wei, founder of the Cross-border Environment Concern Association, urged the Shenzhen government to conduct and release the results of an environmental impact assessment before construction began.
Wei and Yu agreed that environmentalists on both sides of the border should try to get the Shenzhen government to launch a public consultation, and to maintain transparency as the project moved from planning to implementation.
"But I don't think the Hong Kong government will do much about it," Yu said.
And if the past was any indication, he said, attempts might be futile because "Guangdong always focuses on the economy and population flow rather than environmental protection".
Shenzhen had more than 530 hectares of mangrove forest in the early 1980s, one of the mainland's most important wetland conservation zones. Today, less than a quarter of that space - just 130 hectares - remains because of urbanisation, local media say.
The Shenzhen Economic Daily quoted the China Coastal Waterbird Census 2014 report as saying the number of shorebirds living in Shenzhen's mangrove wetlands had fallen 17 per cent since last year.
Xiong Yang, of the Green River NGO, has long studied Shenzhen's mangrove forests and thinks the situation is bleak.
"The new enterprise-headquarters project will be right next to the wetland park - another commercial reclamation project in the Qiaocheng wetlands - and will become a new threat to the nearby Mai Po reserve, even though the developers and authorities have hailed the park's new villas, artificial lake and yacht docks as a haven for birds," Xiong said.
"To make the wetland park attractive to property buyers and tourists, the developers are trying to clean up the area and also bring in seawater. It will make the park look beautiful and clean, but it will be a disaster for the fragile ecosystem."