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The ecology of Hong Kong is mostly affected by the results of climatic changes. Hong Kong's climate is seasonal due to alternating wind direction between winter and summer.

Hong Kong has been geologically stable for millions of years. Flora and fauna in Hong Kong are altered by climatic change, sea level alternation and human impact.

Climate

Main article: Climate of Hong Kong

Hong Kong's climate is subtropical but half the year is temperate. The territory is situated South of the tropic of Cancer which is equal to Hawaii in latitude. In winter, strong and cold wind generates from the North to Hong Kong; in summer, the wind reverses in direction and brings the warm and humid air from the South. This climate would support a tropical rainforest.

Land

The total land area of Hong Kong is 1,076 square kilometers, but about 75% of it is open countryside, which contains more than 2600 species of vascular plants, about 450 species of birds, about 200 species of butterflies, about 100 species of dragonflies, 40 species of mammals, 80 species of reptiles and more than 20 species of amphibians, including some species endemic to the territory.

Species richness in Hong Kong

Hong Kong is considered rich in number of species. The number of species of birds in Hong Kong is one third of that in China while the number of butterflies species is also one sixth of the total butterfly species in China according to surveys reported. ^[1]

Examples of Ecosystem in Hong Kong

Mangroves

Mangroves are habitats of enclosed intertidal mud flats with wave action greatly reduced, located near sources of fresh water. Popular mangrove habitats in Hong Kong are located along Deep Bay, such as Pak Nai and Tsim Bei Tsui, where salinity is very low under the influence of fresh water from the Pearl River, and along some mud flats where salinity is lowered by surrounding streams, such as Three Fathoms Cove and Ting Kok. Trees living in this habitat are called mangrove trees.

The following are the sites of Rocky Shores in Hong Kong:

• Hoi Ha
• Lung Kwu Tan
• Butterfly Beach
• Silverstrand Beach
• Deep Water Bay
• Middle Bay
• South Bay
• Stanley
• Turtle Cove
• Tai Tam

Rocky Shores

The tidal range of Hong Kong is about 2.5 meters and the distribution of species is situated into this area must be tolerant of both conditions that the shores are covered with sea water during high tide and the shores are exposed to the air directly during low tide, for hours or days. Species which have adapted to these different conditions are described as specialized to successfully exploit narrow vertical zones on the rocky shore.

The species inhabiting Hong Kong rocky shores varies in accordance with the exposure to the wave action from the sea. The sessile filter feeding organisms inhabit the wave exposed shores. They are able to attach on the rock surface and remove food particles in the turbulent water while the mobile herbivores and carnivores inhabit in the sheltered shores. The varieties of the organisms also different from seasons, especially in Hong Kong where oceanic currents change with season: very few erect foliose macro-algae are found in summer because they may suffer from the burning heat; a lot of foliose algae are found on the shores in winter.

The following are the sites of Rocky Shores in Hong Kong:

• Luk Keng
• Kei Ling Ha Lo Wai
• Cape D'Aguilar Marine Reserve

Streams

There are two kinds of freshwater habitats: lentic water, such as lakes, ponds, ditches, and lotic water, such as rivers, streams. Streams are an example of a lotic habitat Hong Kong.

There are three main factors to differentiate the habitats in Hong Kong: variability of current, amount of detritus and variable oxygen content. These factors contribute to make the animals adapted in different ways. They have to attach themselves to the surfaces, become predominantly detritus feeders and have a mechanism for obtaining maximum oxygen supply.

The followings are the sites of Streams in Hong Kong:

• Wa Mei Shan
• Lam Tsuen River

Sandy Shores

The following are the site of Sandy Shores in Hong Kong:

• Starfish Bay

Problems

Pollution Problems

General

In 1989, the Hong Kong government suddenly realised that Hong Kong was in danger of becoming a vast, densely populated city. Due to the uncontrollable business and economic growth, the water, waste and air pollution cause an adverse effect on the balance of ecology in Hong Kong.

As the business expands, new infrastructure and construction will be established. Demolitions to make room for this will need to be conducted. Enormous amount of trash and solid waste are brought to the new landfills. It causes serious land and air pollution from the landfills.

Factories, farms and restaurants in the New Territories dump out large amounts of sewage and even untreated waste into the streams and the sea. It makes the New Territories' streams are 'no better than open sewers'. This severe damage is irreversible and the creatures in the sea are the direct victims of the capitalized city’s effort^[2].

The pink dolphin is one of the victims. Under the threat from chemical pollution, increased sea traffic and the destruction of much of the natural shoreline for land reclamation, the number of pink dolphins has dramatically declined as the city continues to develop.

The nature reserve and birds in Mai Po Marsh are the other victims. They are threatened by the pig sewage flooding as well as the increased pollution from Shenzhen. The bird sanctuaries in the wetlands around Mai Po are forced to leave due to the government’s plan to build huge residential housing estates in the New Territories. And the environment around Mai Po is changing – it is no longer a perfect haven for the birds.

The oyster farms have been throttled by a mixture of pollution and competition from cheaper oyster cultivation across the border in China.

Air pollution

Main article: Air pollution in Hong Kong

Air pollution is another serious problem. Smoke-belching factories, ceaseless construction and large numbers of diesel vehicles have made for dangerous levels of particulate matter and nitrogen dioxide. Not only the flora and fauna are affected but also humans. Cases of asthma and bronchial infections have soared in recent years, and doctors place the blame squarely on poor air quality.

Thermal pollution

According to a Baptist University study, daily average minimum temperatures have increased by 0.02 degrees (celsius) annually between 1965 and 2003, due to the "concrete jungle" which traps heat during the daytime and releases it at night. Average daily maximum temperatures have fallen by 0.014 degrees each year, as air pollution is blocking solar radiation. Resulting increased night time ambient temperatures incite families to use domestic air-conditioning, which further compounds the problem^[3].

Research has shown that the ambient air-temperature in urban areas can be some 5°C higher than non built-up areas. The Hong Kong Polytechnic University commissioned NASA to take a high-resolution thermal image of urban Hong Kong by satellite at 22:40 on August 4 2007, which showed at least a 4 degree difference between the coolest areas and the "urban heat islands". The variations are attributable to greater absorbency of man-made materials, and building density which restrict air-flow. The urban heat island had expanded into Hung Hom since January, when the first image was taken.^[4]

"Wall effect"

There has been increasing concern since 2006 over the "wall effect" caused by uniform high-rise developments which adversely impact air circulation. Due to the density of Hong Kong's population and the economies of scale of mass developments, there is the tendency of new private tower block developments with 10 to over 100 towers, ranging from 30-to-70-storeys high. Developers of housing estates are financially motivated to maximise the view, at the expense of the free-flow of air. Huge wall-like estates along the waterfront are often constructed.^[5]

In-fill developments will tend to done by smaller developers with less capital. These will be smaller in scale, and less prone to the wall effect.

Environmental group Green Sense expressed concern that their survey on 155 housing estates found 104 have a 'wall-like' design. It cited estates in Tai Kok Tsui and Tseung Kwan O as the "best examples"^[5]. In May 2007, citing concern over developments in West Kowloon, and near Tai Wai Yuen Long railway stations, some legislators called for a law to stop developers from constructing tall buildings which adversely affect air flow in densely populated areas, but the bid failed.^[6] In 2007, residents of Tai Kok Tsui, increasingly aware of the problem, have been lobbying against further proliferation of such high-rises in their area which threaten the last air corridor.^[4]

Threats to flora and fauna

Destruction of habitat

• Encroachment of the green belt
• Effect of the Building Waste Levy

Illegal Hunting of species by mainland Chinese

With increasing affluence of mainland Chinese, some of them become affable to some luxury flora and fauna, like Podocarpus macrophyllus (羅漢松; Cantonese: lo hon chung) and Cuora trifasciata (金錢龜; Cantonese: kam chin kwai). With ever increasing hunting on some luxury species, they're becoming increasingly rare in South China and hunters turns their heads to the last habitat in the area: Hong Kong.

Introduction of non-indiginous species

Most of the introduced species do little harm to the ecology of Hong Kong. However, some species are invasive and cause massive damage to the ecology and/or economy of Hong Kong.^[7]

For example, the Pinewood Nematode from North America and Pine-needle Scale Insect from Taiwan, which together virtually eliminated the native Pinus massoniana in the 1970s and 80s.^[8]

See also

• Geography of Hong Kong
• Hong Kong Country Parks & Special Areas
• Environment of mainland China
• Hong Kong-Zhuhai-Macau Bridge
• List of protected species in Hong Kong
• Species first discovered in Hong Kong

References

External links

• The World Wildlife Fund (WWF) in Hong Kong
• Environmental Protection Department
• HKNature.net
• HKWildlife.net forum
• HK-Ecosite
• Waterfalls in Hong Kong
• Hong Kong - how to breathe easier

• list of mammals in Hong Kong
• List of birds of Hong Kong

Gallery

Hong Kong Orchid Tree	Fruit of Camellia granthamiana	Lamproptera curius	King Cobra
Burmese Python	Green turtle	Black Kite	Black-faced Spoonbill
Leopard Cat	Chinese White Dolphin