The Effects of Human Activities on Chinese White Dolphin and Leopard Cat in Hong Kong
Hong Kong has a natural environment with high biological diversity, with a wide variety of tropical species 3000 years ago, including elephants, tigers and wild red dogs. However, due to the development of human society to the environment, such as agriculture and urbanization, which seize the natural habitat of most of the wildlife species, result in extinguishing among Hong Kong. Currently, there are 57 existing mammalian species in Hong Kong, while half of them are bats and others are non-flying mammals, which continue to maintain the ecological cycle in Hong Kong. However, the increasing human activities nowadays had made further destruction to the food web of Hong Kong, through affecting the top predator either in the marine environment and terrestrial environment. In the following paragraph, we will make a brief on the effect of human- the hyperkeystone species on the local top predators, such as Chinese White Dolphin and Leopard Cat throughout the years.
To start with, we will first discuss Leopard Cat- a native carnivore in the Hong Kong ecology. Leopard Cat is one of the medium to large domestic mammals belong to the order Carnivora, with a report shown that it is not extinct in wildlife (Or lack in report of discovery in recent years). There once have higher-order predators such as Leopard or tiger in Hong Kong, however, they were considered as extinct because of no report in the discovery of the species in the past few years, i.e: the last report of killing a South China Tiger locally was in 1942. Therefore, consider the possible largest domestic predators which exist in Hong Kong currently, Leopard Cat will be the top predator in the terrestrial environment. For marine top predators, the Chinese white dolphin is considered as one of the top predators due to their high activities around the seas in Hong Kong, and its natural role in the ecology as a predator. Actually, there are many types of whales and dolphins in Hong Kong waters, but Chinese White Dolphins is the best species with sufficient records to shown the impact of human as hyperkeystones.
Leopard Cat is considered the middle hierarchy mammals before human activity caused major impact to the terrestrial environment, due to larger Carnivora such as Leopard or Tiger as the top predator of the environment. However, Leopard Cat now confronts the same problem as other Felidae. Leopard Cat’s fur is considered luxury which is highly demanded in China, especially the southwestern part. Therefore, in the 80s to the 90s, a wide range of hunting in Leopard Cat was operated in order to obtain 150000 furs per year, for internal consumption and export to other countries, until the halt in hunting Leopard Cat in China in 1993. Still, there was still illegal hunt in Leopard Cat for either their fur or their meat, even for pet trading overseas. Besides overhunting, habitat loss is another major threat Leopard Cat face, like other mammals. Leopard Cat major habitat is the secondary forest, which is hugely deforested by human in the past decades, which make their mortality rate become higher, result in population drop. The last reason is the intentional killing on Leopard Cat because of the belief in pests. Leopard Cat’s main prey including young ungulates, hares, birds, etc, resulting in the chance of hunting herds. Therefore, farmers may try to hunt Leopard Cats rather than repel, or even try to poison them, making the mortality rate higher when Leopard Cats invade human areas.
Besides the terrestrial environment, the marine environment is also under the influence of human activities. Through monitoring the behaviour of the Chinese White Dolphins, we can explain the reason for White Dolphins being endangered. In the past decades, the number of Chinese White Dolphins drop drastically from 188 to only 47 left in the past 15 years. It is caused by serval factors: Underwater Noise Pollution, Vessel collision and habitat losses. Underwater Noise Pollution is the highest threat to the survival of the Chinese White Dolphins. Dolphins require echolocation for their daily activities, including hunting, communication, and navigation. Underwater construction and marine traffic can interfere with the dolphin’s echolocation capability, which can result in the death of dolphins due to misleading information from false echolocation. Not only the ship interferes with the echolocation ability of the dolphins, but they can also result in collisions with the dolphins. According to WWF, it is reported that there are scars and marks found on the bodies and the fins of the dolphins, which is believed to be caused by the propellers. Habitat loss is another major factor that will affect the survival of the Chinese White Dolphins. Many infrastructure projects such as Hong Kong-Zhuhai-Macao Bridge or the third airport runway is a huge project require reclamation, which will reduce the suitable waters for the dolphins and force them to move away. Furthermore, the reclamation progress can result in noise and other pollution to the waters, which may alter the behaviour such as breeding and hunting of the dolphins.
In conclusion, human is an important hyperkeystone species to the wildlife, which can heavily impact both the terrestrial environment and the marine environment during the urbanization.