Ma said there are now at least 5,000 crested ibises in China.

The population growth of such species proves that measures introduced by the Chinese government for biodiversity conservation have been effective, he added.

China started to pilot logging bans in State-owned natural forests in 1998, Ma said. The ban was fully implemented in all State-owned natural forests in 2017, bringing the main habitats of wild animals under conservation.

However, Ma said rising animal populations have brought a new challenge, as the creatures roam far beyond the nature reserves allocated for them.

When the crested ibis was rediscovered, its habitat was near Yaojiagou village, Yangxian. Currently, the birds' range covers tens of thousands of square kilometers, he said.

The red line system can help China cope with "the new situation", Ma said, adding that nature reserves usually occupy relatively small areas, so instead of expanding reserves, the system can encircle some species' dispersed habitats and bring them under protection.

Instead of making all red line areas subject to rigid management that bans human activities, Ma suggests that to manage the system, tailor-made measures should be adopted based on the needs of species.

For some species with small populations, key locations should be set up within the red lines to increase protection. Measures should also be taken to prevent habitats being damaged, he said.