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The Environment
The northeastern New Territories reveals the most comprehensive stratigraphy of sedimentary rocks in Hong Kong, ranging from Devonian sandstone and conglomerate aged about 400 million years to Paleogene siltstone formed 50 million years ago.
Despite its small size, Hong Kong has a great variety of coastal landforms, including sea cliffs, sea caves, sea arches, geos, tombolos, wave-cut platforms, sea stacks, notches and blowholes.
While most of the hexagonal volcanic rock columns in other regions of the world are composed of basalt lava, those in Sai Kung are made up of silica-rich rhyolitic volcanic rock. Apart from its extraordinary composition, the columns are considered unique for their size, with an average diameter of 1.2 metres, and the large area they cover, of more than 100 sq km.
A series of fifteen 1:20,000-scale geological maps and six accompanying geological memoirs have been produced by the Hong Kong Geological Survey. Two summary memoirs and a set of 1:100,000-scale geological and thematic maps have been published, in Chinese and English, synthesising and giving a popular account of local geology. Geological information can be accessed from the Civil Engineering and Development Department's website.
Flora
Hong Kong is situated near the northern boundary of the distribution of tropical Southeast Asian flora, sharing similar species and structure with the flora of Guangdong. Despite its small size, Hong Kong has a rich flora with about 3,300 species of vascular plants, of which 2,100 are native to the territory.
The major types of vegetation cover comprise woodland, shrubland and grassland. Remnants of the original forest cover can still be found in steep ravines or behind traditional villages in rural areas. They have survived as a result of their location in precipitous topography and the moist micro-climate, or because they are protected for cultural reasons.
Continual afforestation efforts coupled with conservation measures have transformed formerly bare hillsides and slopes into impressive woodlands. Besides greening and beautifying the countryside, woodlands are important habitats for wildlife and are essential to protect water catchments from soil erosion.
Fauna
Terrestrial
The climate and physical environment provide a wide range of habitats and support for a rich and varied fauna that includes more than 530 species of birds, more than 50 species of mammals, over 100 species of amphibians and reptiles, 236 species of butterflies and 123 species of dragonflies.
Besides the rich terrestrial fauna biodiversity, a number of species are endemic to Hong Kong, including the Romer's Tree Frog, Bogadek's Burrowing Lizard, Hong Kong Tusktail and Hong Kong Clubtail. Newly recorded species are discovered from time to time. Globally endangered or threatened species, such as the Three-banded Box Turtle, Yellow-breasted Bunting, Short- legged Toad, Green Turtle and Chinese Pangolin, can also be found.
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