Effective decision-making regarding the type and location of future development is essential to the pursuit of sustainability. In order to direct development toward areas where it is most suitable and away from areas with existing habitat value, a detailed understanding of the natural habitats of Hong Kong, and accurate mapping of their locations is essential. For these reasons, a comprehensive and robust habitat mapping system is a fundamental tool for planning future development in Hong Kong.

It is likely that the sustainability assessment process developed under the SUSDEV 21 study will include indicators relating to habitat area or value. In order to support application of these indicators, the location and areal extent of key habitats must be identified. Furthermore, developing consensus on target values (ie whether certain habitat types should be maintained, expanded or reduced) will be facilitated by an updated plan showing the present situation. The availability of this information in digitised format will allow users to specify display of different map themes and assist in visualisation of the effects of proposed landscape changes.

A particularly useful application of the system would be to provide for quantification and assessment of existing natural habitats. For example, if a proposed development in the New Territories involved removal of a certain hectarage of forest, the habitat map could be used to reveal the total loss to remaining habitat of the type that the development would constitute. The size and location of the forest could also be assessed in the context of surrounding areas and, using existing information on the ability of fragmented habitats to support various ecosystem components, its ecological function. In combination with ranking areas of Hong Kong on conservation value, the habitat map will provide a powerful tool for development planning and siting.

Sustainable development also requires effective conservation and management of natural resource areas which serve key ecosystem or societal functions. Sustainable development planning therefore is greatly facilitated by a system which can highlight important areas for protection. Development of a GIS-based ranking system will allow sites to be assessed on a common basis without risk of losing critical detailed information in the process.

Whereas the habitat mapping tasks will enable specific areas of land to be plotted by physical and biological characteristics and compared with remaining similar areas in Hong Kong, the ranking of habitats for conservation value will allow prioritisation of key areas of habitat for protection. Although such a ranking would certainly not obviate the need for further assessment should development proposals proceed, such a system could act as a useful initial screening tool in site selection discussions.

Within the SDS to be developed by the SUSDEV 21 Study, conservation ranking information can be used to evaluate the existing baseline conditions against any indicators involving the area of land with various levels of conservation status, the area available for nature recreation, and/or any trends in disturbance/disruption to conservation areas. By providing several categories of classification for conservation protection, this option can also form the basis for future Government policies on land use and natural resources protection.