Research On Landscape Pattern And Stability Of Yuanyang Hani Terrace

Hani terrace landscape in Ailao Mountain (Yuanyang) is a unique representative example of subtropical mountainous agricultural landscape in Yunnan Province. It has the value of World Natural and Cultural Heritage. To explore the characteristics of this unique natural and cultural landscape and its formative mechanism and to promote its sustainable existence and being protected, this research is based on the related theories: landscape ecology, geoinformation atlas, sustainable development and so forth. With the help of RS and GIS, the relationship between the static and dynamic characteristics of Hani terrace landscape in Yuanyang and the stability of terrace is studied systematically and thoroughly. With this basis, the theory and the research content of geoinformation Tupu and landscape Tupu is studied preliminarily.Main Research Achievements:1. By means of the landscape pattern analysis software:Fragstats and AreView3.3, the landscape pattern of the Yuanyang terrace is analyzed. The findings are that the dry land (27.8%), the land with trees (25.3%), the shrubbery (17.2%) and the water terrace (16.0%) take up a large proportion of the Yuanyang terrace landscape; moreover, the arable land (the dry land and the water terrace) and the woodland (the shrubbery and the land with trees) both take up a proportion of more than 40%, which is seen as an advantageous pattern. The number of the inhabitant patches (552) exceeds one fourth of the total number of the landscape (1989), and the patch density (24.88/10000hm2) ranks the first, which shows the characteristics of the typical mountainous agricultural landscape. There are patches with an area from 10 to 50 hm2 in the landscape. But 44.2% of the landscape belongs to the level that the patch area is larger than 100hm2, which shows that there are huge patches with absolute predominance and numerous medium-sized patches.And their alternative distribution forms the pattern characteristic of being relatively broken and of medium-connectivity. The discrepancy lying in the length of the adjacent edge, the number of the adjoining type and the amount percentage among the different landscape types is distinct. Most of the types adjoin the dry land; hence, they are heavily influenced by the dry land. The cultivating radius in the landscape is 799.7m and about 60% of the arable land lies in this area; about 40% of the water terrace is far away from the rural habitats, and it is hard to cultivate. The water terrace area occupies a large proportion of the landscape and the average patch area is quite large. This is the important pattern characteristic to form the scale beauty of the terrace. The arable land and the woodland are balanced in the landscape, and the three-dimensional distributional pattern of wood-and-village fields is a significant characteristic of the harmonious beauty of the terrace.2. The analysis of the landscape's dynamic variation is conducted based on the remote sensing images of Yuanyang County in the years of 1974,1992 and 2000. The findings are (1) the dominant type of landscape structure of the terrace in 1974 was the arable land (40.47%) and the woodland (48.62%), then changed to be the arable land (40.47%)and the woodland (48.62%) in 1992, further developed to the arable land (39.53%) the woodland (44.02%) in 2000. This demonstrates that during the period of research, the landscape structure of the Yuanyang terrace was relatively stable. (2) The interconversion of various landscape types in the research area was complex over those years from 1974 to 2000. This conversion occurred mainly among the land with trees, the shrubbery, the barren grassland, the water land and the dry land. The most obvious evolution process includes the conversion from the dry land to the water land, from the dry land to the barren grassland, from the land with trees to the shrubbery, from the shrubbery to the unemployed land. (3) In terms of the landscape quality, from 1974 to 1992, the variety and the evenness degree of the terrace landscape was on the decline, while the advantage degree of the landscape and the degree of destruction were on the increase. This shows that the landscape pattern of the Yuanyang terrace landscape evolves from the pattern of small patches and many landscape types commonly dominating into the pattern of huge patches and single type. From 1992 to 2000, the landscape's variety, evenness and the index of the spreading degree were on the rise, while the degree of destruction was on the decline comparing to the previous period. This demonstrates that the terrace landscape is also controlled by many advantageous patch types which have a better connectivity, and the landscape is developing positively.3. The landscape stability of the Yuanyang terrace is comprehensively analyzed through the quantitative landscape index, the terrace landscape vertical pattern characteristic, the internal structure variation of the landscape, and the function of the ecological system. The findings indicate that in the period of the research, the Yuanyang terrace landscape was basically stable; "Forest-village-terrace-river" structure, a four-in-one vertical and spatial structure forms the unique flow of energy and matter inside the terrace landscape, which is the premise of the stability of Hani terrace landscape. The findings also show that the Hani forest protection through divine and human power and long-term management for the terrace and the village division, a solution to the increase of population, is a significant factor contributing to ensuring the continuance and the stability of Hani terrace landscape. The forest and terrace ecological subsystem both serve the terrace agricultural landscape, thus forming the mechanism of stability for the Hani terrace landscape.4. The tupu method is introduced into the research of the landscape's spatial pattern and the landscape variation. The graphical thinking-mode of applying geoinformation tupu to reflecting the spatial pattern and temporal evolution, the pattern of landscape ecology and the quantitative thinking-mode of process research are combined. The building-model of the methodology of the landscape information atlas is formed preliminarily. The results show that:(1) The established land use spatio-temporal change premonition Tupu is more visually revealing the basic pattern of land use change in the study regions, and provides a spatio-temporal expression way. (2) The land use patch shapes and spatial expansion Tupu can provide the macroscopic and microscopic information of land use dynamic change. Through establishing mathematical models to analyze the expansion intensity and expansion patterns of various land use types, the land use spatial expansion process can be visualized, abstracted, and modeled. (3)Through the horizontal (the relation between patch area and landscape index) and vertical (the interannual variation of landscape index) quantitative description of indexes, the land use change and landscape characteristic Tupu has established the landscape index system for measuring the changes of spatial patterns to analyze the change trend of various land use types (seen as the landscape types) in the study regions, and their relations with human activities, so provides the basis for the formulation of sustainable land use policies in the study regions.(4) By means of the analytical method of equal-step-length but distance-varying buffer zone, the VCM curve is established. This curve can describe the spatial distributional characteristics of the various landscape patch types and the variation of the spatial distributional characteristics in different phases of the research more directly and clearly.