TNAG-0532-FCO40-627-Conservation-of-wildlife-in-Hong-Kong-1976 — Page 58

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6.3.3 These animals show many adaptations to their specialised environment and the mudskippers of the genera Periophthalmus and Botriophthalmus are of particular interest because of their almost "amphibian" existence between land and water. The fauna associated with the mangrove community must surely offer one of the best opportunities for demonstrating "adaptation" to ecology students in Hong Kong.

6.3.4

Characteristically estuaries tend to be more productive than either the sea on the one side or the freshwater drainage on the other. This high productivity (both primary and secondary) results in an abundant food supply for wading birds and ducks. Without this food supply the numbers of birds in the area would certainly be greatly reduced.

7. International Importance of the Marshes

7.1

Szijj (1972) lists a number of factors to be taken into account when considering the international importance of wetland sites, several of which are relevant to the Deep Bay/Mai Po Area.

7.1.1

Wetlands especially valuable for educational purposes Arcas within easy reach of major centres of human population may have a considerable educational value (a good example being the North Bull Island, Dublin). Although at present the Marshes are virtually unused as an 'open air classroom', the area has very considerable educational potential and this should be exploited.

7.1.2

Special types of wetland This category covers types of wetland which are under heavy economic pressure and are rapidly disappearing in their present form. The dwarf mangrove community in Hong Kong is increasingly being destroyed by reclamation projects and the Marshes contain the largest area of this habitat remaining in the colony.

7.1.3

Wetlands of importance to endangered species 'Any breeding or other resort, which is still in regular use, is of international importance, irrespective of the numbers occuring there' (Szijj loc. cit.). While only two species listed in the I.U.C.N. Red Data Book havə occurred occasionally on the Marshes (Japanese White Stork and Swinhoe's Egret), four other species which may be added to the Red Data Book in the near future (Asiatic Dowitcher, Spoon-billed Sandpiper, Spotted Greenshank and Saunders' Gull) have been recorded more frequently. Very little is known of these four species but all appear to have small populations and very restricted breeding distributions (Dement 'ev and Gladkov 1969, Vaurie 1965). The three wader species are thus vulnerable to the great industrial expansion which is currently taking place in the Siberian region (see Kistchinski 1973 and McClure 1974). Saunders' Gull may be similarly threatened in China.