Getting Active

Contrary to common belief, the best way to conserve species in the wild does not always mean minimising human activity in an area. At times, human intervention is required to help a habitat thrive. Some man-made habitats are home to many species and require regular maintenance to preserve their ecological value. Active management is the term for these types of conservation actions.

“It is not easy to understand what active management is in contrast with abandonment,” says Tony Hung, Conservation Officer, Mai Po Projects, WWF-Hong Kong. “But the term ‘active management’ may not only refer to actively managing a habitat. It is also important to note that this type of ‘interference’ is a proper conservation action.”

Active management goes beyond preserving a habitat simply as it is. The continuous function of a habitat is important for the wildlife that depend on it as a feeding ground. Birds, in particular, benefit from different farming processes in traditional agricultural or aquatic culture.

In Hong Kong, wetland habitats are the main targets for active management. The city’s most important wetland area, the Mai Po Nature Reserve, has been actively managed by WWF since 1983. However, humans have shaped and modified the wetlands in Mai Po and Inner Deep Bay for a long time prior to WWF’s involvement.

In the early 20th century, large areas of mangroves and marshes around Mai Po were reclaimed for rice cultivation, shrimp farming, oyster cultivation and salt production. In the 1940s, 300 hectares of mangroves in the area were modified into shallow tidal shrimp ponds, called gei wai, replacing many rice paddies in the Deep Bay area. This type of shrimp farming utilises the rich productivity of estuaries.

By the 1960s, gei wai farming became less profitable. Many farmers modified these gei wai into deep-water fishponds, which became the dominant type of land use in the 1980s. Unlike a natural habitat such as a forest, coral reef or rice paddies, gei wai and fishponds will not be of maximum benefit to wildlife if left alone. It’s up to humans, who intervened in the landscape to begin with, to carry out active management. This is where WWF enters the picture. Hong Kong has many man-made habitats that have undergone drastic transformation or destruction caused by on-going development. It is crucial to practice active management in order to maintain the ecological value of the remaining habitats.

“Apart from abandonment, there are other threats to Deep Bay wetlands, such as illegal dumping of construction materials into fish ponds and intensive commercial farming,” adds Hung. “There is an urgency for active management using traditional farming practices or enhanced conservation management.”

To get a better understanding of what active management entails, consider a gei wai operation. Following traditional practice, water is usually drained down in winter when the fish are harvested. Towards the end of harvesting, many small fishes and shrimps get trapped in the shallow waters, providing a feast for migratory water birds. Without active management, none of this would happen and migratory birds would not benefit. In the meantime, the rich sediments from the Pearl River accumulate in the gei wai through the water exchange process. Over a period of time, without intervention, the gei wai floor will rise. As well, reed or terrestrial vegetation will encroach upon the wetland habitat, reducing its attractiveness for water birds. The terrestrial water found in these wetland habitats may eventually dry out, and the area will no longer be wetland. Management work is needed to remove the vegetation and lower the gei wai floor to maintain it as a rich feeding spot for migratory birds.

In addition to the Mai Po Nature Reserve, other important local wildlife habitats need proper active management in order to maintain their ecological value. Wet agricultural land in Long Valley is also a bird hotspot and appropriate active management is crucially needed for it to remain a viable habitat for waterbirds.

In the meantime, WWF has pioneered an eco-fish farming project in Deep Bay to encourage traditional fishing management. By practising active management, we can better meet conservation goals and prevent problems before they arise so that wildlife can continue to thrive.