THE ENVIRONMENT
common, as are wasps and metallic-coloured beetles. Of particular interest is the giant red-spotted longhorn beetle which feeds on mountain tallow and wood-oil trees. Many other species of longhorn beetles infest living or weakened trees.
Since its introduction into Hong Kong in 1938, the African giant snail has become a major pest to vegetable crops and gardens. Farmers are also troubled by several types of slugs. One of these, veronicella, is large and black and sufficiently different from the other slugs to be placed in a separate family.
Aquatic Fauna
Hong Kong lies some 320 kilometres south of the Tropic of Cancer on the southern coast of China. Located at the junction of the vast temperate Palaearctic Japonic zoogeographical regions and the huge Indo-Pacific Province, Hong Kong possesses very diverse varieties of aquatic animals and plants. There are over 150 commercially important species of fish, crustaceans and molluscs.
The waters of Hong Kong can be divided into three sectors. Under the influence of the Pearl River, the biggest river in southern China, the western sector is predominantly brackish. The area to the east is more oceanic while the central sector is transitional between brackish and oceanic. In some localities, notably the Tolo Harbour region, pollution associated with recent rapid urban development has decimated the abundance and diversity of aquatic life. Pollution-sensitive organisms such as coral are now found only in a few clean yet remote oceanic areas in the northeast. Nevertheless, various locations still serve as spawning and nursery grounds for many aquatic species, and these in turn attract transient predators such as Spanish mackerel, little tuna, dolphinfish, sailfish and sharks.
Shark sightings have been recorded in Hong Kong waters. Most are small to medium in size and pose little danger to humans. However, two fatal attacks, believed to have been caused by tiger sharks, were recorded in June in Sai Kung waters.
Four species of whales and eight species of dolphins have been recorded in Hong Kong waters and strandings occur quite frequently. The black finless porpoise and the Chinese white dolphin are the most common in terms of occurrence. In 1993, 12 strandings were reported.
Flora
Situated near the northern limit of the distribution of tropical Asian flora, Hong Kong has an abundant variety of plant life. It is estimated that there are about 2700 species of vascular plants, both native and introduced.
With the introduction of various conservation measures, hillsides and slopes which were formerly bare ground have now been planted with trees of both local and exotic species. In addition to greening and beautifying the countryside, woodlands are also important as habitats for wildlife, in the management of water catchments and in providing recreational opportunities for the public.
Remnants of the original forest cover, either scrub forest or well-developed woodlands, are still found in steep ravines. They have survived the destructive influences of man through their location in precipitous topography and the moist winter micro-climate.
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