英语论文网

nd agricultural conversion processes . DEFENDING THE SECURITY OF PROCESSES IN RED STONE NATIONAL PARK: A CASE STUDY Red Stone National Park is 313 square kilometers in size (Figure 2). The dominant regional natural vegetation is composed of sub-tropical Figure 2 The landscape of the Red Stone National Park in South China evergreen forests which have been seriously destroyed at the peripheral area with some isolated remnant patches scattered in the remote areas. The landscape is made up of hundreds of heavily eroded rocky hills, square with flat top and steep slopes. This unique land form is the primary factor affecting the distribution of soil, vegetation, wildlife habitats, visual quality and agriculture. The remnant biological islands are extremely valuable in terms of biodiversity conservation and landscape restoration. The visual quality is extraordinary . It is one of the major tourist attractions in south China. The fertile soil and sub-tropical climate make this land one of the most productive agricultural areas. About twenty thousand farmers live in seventy villages scattered in the small alluvial planes in this hilly landscape. The problems this national park now faces are typical of other national protected areas, namely, the conflicts between development , ecological and visual conservation. Landscape planning in this park is a defensible procedure dramatically taking place among defenders of various processes. As a result, this case study a an illustrative example for the SP approach. Three processes are concerned in this case study: ecological, visual perceptual, and agricultural. The objectives in this case study are to explore an effective way of defending various landscape processes in this national park by identifying and applying SPs, and to demonstrate how GIS can be integrated into the defensible procedure of landscape change and decision making. Security patterns in the Red Stone National Park Ecological SPs: Ecologists' Defensive Frontiers Ecological processes concerned in this case are species dispersal and maintenance. Three groups of species are targeted: medium-sized mammals (Cervidae and Viverridae families), pheasants (Phasianidae family) and amphibians (Cryptobranchidae and Ranidae families). These species are native to this region and have an endangered status. Ecological SPs are identified by analyzing accessibility surface that represent the potential coverage by the species of our concern. Accessibility surfaces are developed using a minimum cumulative resistance(MCR) model (Knaapen, Scheffer and Harms, 1992; Yu, 1995b), this model conceives the dynamics of species dispersal as a function of sources, distance and intermediate landscapes. Native habitats of the target species are taken as sources of dispersal. Intermediate landscapes are evaluated for their resistance to the dispersal of species, and the dynamics of the dispersal process is simulated based on the cumulative resistance to the dispersal of a certain species. Comparative resistance values are assigned to various landscape attributes. Various factors such as cover, slope, elevation and aspect may contribute to the resistance value of each cell of the landscape. The probability of successful access to a cell by a species can be expressed as: i = n Accessibility = f Min _(Di * Ri) i = 1 where f is some unknown but monotonically decreasing function. Di and Ri respectively represent the distances (number of cells) and resistance