The environment of Hong Kong features a subtropical climate with a monsoon season and a high level of biodiversity. However, the flora and fauna of Hong Kong face threats from climate change, rising sea levels, and land development.
Hong Kong has a subtropical climate with temperate conditions for about six months of the year. The monsoon season lasts from April to September with July to September being the most likely months for tropical cyclones to occur. During the hot, humid summers, the average daily maximum temperatures range from 26°C at night to 31°C during the day, with late May to mid-September seeing the highest temperatures. Hong Kong receives between 1400 to 3000 millimetres of rain per year and 80% of that occurs from May to September. Of these, June and August are the wettest months, with rain falling on almost four out of seven days. The winters are dry and temperate. December and January, are the driest months, with an average of only one rainy day per week.[1]
Land
The total land area of Hong Kong is 1,076 square kilometres, but about 75% of this land is open countryside.[2]
Hong Kong is home to many species despite being one of the most densely populated areas in the world. In a 2025 report, the World Wide Fund for Nature (WWF) Hong Kong counted 584 bird species, 272 butterfly species, 134 dragonfly species, 71 reptile species, 70 freshwater fish species, 24 amphibian species, 24 freshwater crustacean species, and 18 species of medium to large non-volant (flightless) land mammals.[3] In addition to the 8 groups assessed in the WWF report, Hong Kong has 25 species of bats, 20 species of marine mammals, 120 species of intertidal invertebrates, about 350 species of angiosperms and gymnosperms,[4] and 11 species of small non-volant land mammals.[5]
In 2020, the BBC reported that the population of the critically endangered pink dolphin (Sousa chinensis), also called the Chinese white dolphin, had dropped by 60% around the area of construction for a bridge between Hong Kong and Macau.[6][7]
Numbers of the endangered black-faced spoonbill (Platalea minor) wintering in Mai Po Marshes rose from roughly 35 in the late 1980s to 152 after 10 years. About 400 were spotted near the end of 2000.[8] Despite an increase in the worldwide black-faced spoonbill population from 2024 to 2025, the local population decreased from 375 to 328.[9]
Hong Kong has 733 kilometres of coastline[11] with a tidal range of about 1.4 metres.[12] Coastal habitats are broadly categorized as soft or rocky shores, with rocky shores being more exposed to tidal and temperature changes and soft shores being more sheltered.[13]
Rocky shores
The distribution of species situated in rocky shores must be tolerant of conditions when the shore is covered with seawater at high tide and when the shore is directly exposed at low tide. Mobile species adapt to these varying conditions by successfully exploiting microhabitats such as cracks and crevices, or pools of water that remain during low tide. However, sessile organisms that filter-feed, like barnacles and oysters, may die in large numbers during the heat of summer, then recolonize during cooler months.[14]
Rocky shores can be categorized according to how exposed they are. Tai Tam and Tolo Harbour are two areas that have sheltered rocky shores, while exposed rocky shores can be found at Big Wave Bay and Shek O. Areas like Stanley and Middle Bay are semi-exposed.[14]
Soft shores
Soft shores occur in sheltered areas with low wave disturbance. This allows for the deposition of finer sediment than on rocky shores. The amount of sediment varies and can result in different types of habitat such as mudflats, sandy beaches, and mangrove forests.[15]
Mangroves
Mangrove forests are habitats in tropical and subtropical intertidal zones, occurring on soft shores that receive tidal flushing from nearby fresh water sources. The Pearl River is one such fresh water source and it promotes mangrove growth in the Deep Bay area. Of the eight species of mangrove local to Hong Kong, Kandelia obovata is the most common.[16]
There are two kinds of freshwater habitats: lentic (still, or very slow moving) water, such as lakes, ponds, ditches, and lotic (flowing) water, such as rivers, streams.
There are three main factors to differentiate the habitats in Hong Kong: variability of current, amount of detritus and variable oxygen content. These factors influence animals' various adaptive responses. They have to attach themselves to the surfaces, become predominantly detritus feeders and have a mechanism for obtaining maximum oxygen supply.
The following are the list of rivers in Hong Kong:
In 1989, the Hong Kong government realised that Hong Kong was in danger of becoming a vast, densely populated city. Due to the growth of the economy and business sectors, the water, waste and air pollution cause an adverse effect on the balance of ecology in Hong Kong.
Factories, farms and restaurants in the New Territories dump large amounts of sewage and even untreated waste into the streams and the sea. It makes the New Territories' streams be 'no better than open sewers'. This severe damage is irreversible and the creatures in the sea are the direct victims.[18]
The oyster farms have been throttled by a mixture of pollution and competition from cheaper oyster cultivation across the border in China.
Air pollution is another serious problem. Smoke-belching factories, intense construction and large numbers of diesel vehicles have led to dangerous levels of particulate matter and nitrogen dioxide. It's not only the flora and fauna that are affected – humans are too. 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 urban heat island effect, 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 blocks solar radiation. Resulting increased nighttime ambient temperatures incite families to use domestic air-conditioning, which further compounds the problem.[19]
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 4 August 2007, which showed at least a four-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 that restrict air-flow. The affected area had expanded into Hung Hom since January, when the first image was taken.[20]
Wall effect
Highly-dense buildings can be seen in Tseung Kwan O.
There has been increasing concern since 2006 over the wall effect caused by uniform high-rise buildings that block most air circulation. Due to the population density of Hong Kong and the economies of scale of mass developments, most new tower block developments are mass-constructed in groups of 10 to 100, ranging from 30 to 70 stories high. Developers of housing estates are often financially motivated to maximize view at the expense of air circulation. Huge wall-like estates along the waterfront .[21]
In-fill developments are typically constructed 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".[21] In May 2007, citing concern over developments in West Kowloon, and near Tai Wai and Yuen Long railway stations, some legislators called for a law to stop developers from constructing tall buildings that adversely affect airflow in densely populated areas, but the bid failed.[22] In 2007, residents of Tai Kok Tsui, increasingly aware of the problem, have been lobbying against the further proliferation of such high-rises in their area that threaten the last air corridor.[20]
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 the mainland, some mainland Chinese people become able to afford luxury flora and fauna like Podocarpus macrophyllus (Cantonese: 羅漢松; Jyutping: lo4 hon3 cung4 ) and Cuora trifasciata (Cantonese: 金錢龜; Jyutping: gam1 cin2 gwai1). Some of these species are in danger of extinction due to increased hunting.
Introduction of non-indigenous/invasive 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.[23]
Examples are 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 1980s.[24]
↑ Hui, Tommy; Lau, Michael; Lau, Tobi; Leung, Bonnie; Lo, Yik Fui Philip; So, Ken; Sung, Yik Hei; Yu, Yat Tung (2025). Or, CKM; Chan, BPL (eds.). "The State of Hong Kong Biodiversity 2025"(PDF). World Wide Fund for Nature Hong Kong. Archived(PDF) from the original on 16 September 2025.
↑ "Mammals". Agriculture, Fisheries, and Conservation Department | The Government of Hong Kong Special Administrative Region. Archived from the original on 8 September 2025. Retrieved 16 September 2025.
↑ "Horseshoe Crabs in Hong Kong". afcd.gov.hk. Agriculture, Fisheries and Conservation Department. Archived from the original on 20 January 2024. Retrieved 20 January 2024.
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