File photo shows researchers looking through high-powered binoculars in search of one of the earth's rarest dolphins in China's mighty but polluted and traffic-choked Yangtzi river. From tigers to dolphins, animal populations in many of China's ecosystems have plummeted under decades of development and urbanisation, a World Wildlife Fund study said.

From tigers to dolphins, animal populations in many of China's ecosystems have plummeted during decades of development and urbanisation, a World Wildlife Fund (WWF) study said Wednesday.

The conservation group highlighted about a dozen species in different across the country in its third China Report, saying numbers have fallen dramatically over the years.

"The populations of more than 10 flagship and keystone species in China have undergone marked decline that was particularly severe between the 1960s and 1980s," the report said.

According to findings compiled by WWF from various sources, the dolphin population crashed by 99.4 percent from 1980 to 2006, while that of the Chinese alligator fell by 97 percent from 1955 to 2010.

numbers slumped by 92 percent from 1975 to 2009 due to hunting, deforestation, habitat loss and intensified human activities, it said.

But the study noted that four animal types, including China's "star species" the , had seen gradual recoveries due to greater conservation and reintroduction efforts.

This picture taken on June 16, 2011 shows a landslide on the Yangtze River in Badong, in Hubei province. From tigers to dolphins, animal populations in many of China's ecosystems have plummeted under decades of development and urbanisation, a World Wildlife Fund study said.

"You may know that the efforts to protect these four types have been much greater, and their numbers may have started to rise," said Li Lin, WWF's deputy country representative.

"But for the other animals you can see that, in a striking and sad way, their populations have gone down."

The study is part of a broader effort to compile decades of —including size, density and capture rates—for hundreds of species to build a "living planet index" for the country.

In a separate set of indicators updated from its latest report in 2010, the study said China was using resources such as cropland and forests at 2.5 times the rate than they could be regenerated.

This imbalance of China's ecological demand versus supply would impact the rest of the world, said Jim Leape, the director-general of WWF International, at a press conference in Beijing.

"That consumption is putting much more pressure on resources here in China than its resources can sustain" and on "resources on other continents than those continents can sustain", he said.

By comparison the world was using resources at a rate 50 percent faster than they could be regenerated, the study said.

The factors behind China's ecological footprint reflected its economic growth, urbanisation and spending on infrastructure, the report said.

The per capita ecological footprint in cities was double that of rural areas, and higher in the east—which is more developed with greater population densities—than in the rest of the country.