哀牢山区哈尼聚落空间格局与耕作半径研究

Spatial Pattern and Farming Radius of Hani's Settlements in Ailao Mountain Using GIS

以哀牢山区元阳梯田景观中的哈尼聚落为研究对象,用FRAGSTATS计算景观格局指标,用GIS的统计功能、切割运算及缓冲区分析方法,得到斑块粒度、景观类型空间邻接比例、聚集程度及聚落耕作半径等。结果表明:①景观具有耕地与林地占优势地位且两者面积相当的均衡格局特征,聚落是区内斑块数最多的景观类型;聚落的平均斑块面积小且密度大,空间分布类型在各层次上都表现为随机分布,与旱地、水梯田和有林地的空间邻接长度和数目均都较高;②缓冲区分析方法确定的聚落耕作半径存在区域差异。景观水平上的耕作半径为799.7m,约60%的耕地在耕作半径内,有2/5的水梯田离聚落较远;中部亚区耕作半径827m,无论是耕地还是林地类型,其缓冲区内斑块面积占其实际面积的比例都较南北两个亚区高,体现出该区耕作相对容易,具有耕地与林地相间分布的特征;③在局地差异极大的山区,包含在无地表差异的聚落耕作半径内的耕地面积比较有限。以耕作半径为基础,综合参考耕地的坡度、产出等特征,可为合理的退耕还林提供参考。

The Yuanyang terraces, famous with its large area, wide distribution, astonishing construction and infrequency in world, was designated as the core area of the cultural landscape of Hani terraces by the government of Honghe district, Yunan province, China. The terraces are the physical basis of Hani peoples＇ life and the symbolization of Hani peoples＇ spirit. And the cultural landscape of Hani terraces is the model of sustainable land-use and harmonious human ecosystem between culture and nature. In this paper, the Hani＇ s village in the landscape of Yuanyang Terraced Fields of Ailao Mountain was selected as study area. The pattern indices were computed and analyzed using FRAGSTATS. The granularity, the spatial neighboring length and number between the village patches and other patches, the distributing types and farming radius were calculated using Geographic Information System. The results indicate that： 1 ） Both the farmland and forestland occupy a big landscape;2） The village patches are dominating part of the landscape, forming an interlaced pattern of in the landscape with features of small mean area of patches, high density and random distribution at all levels;3 ） All of the arid farmland, the irrigated terrace land and forestland have high neighboring length and number with the village patches; 4） The farming radius is differed in regions. It is 799.7m at landscape level, and about 60 percent of the farmland is located within the farming radius, and two fifth of irrigated terrace land is far from Hani＇ s village patches. In the middle part of Yuanyang County, the farming radius is 827 meters and the percentage of patch area both farmland and forestland in buffer zone to the actual area is the highest among the three part of Yuanyang county, which indicate that the region has better farming conditions and the farmland is interlaced with forest;5） In the mountainous region, because of the complex topography and differentiated farming pattern it is limited to include all of the farmland to make discussion. In recent years, China has put forward a strategy to protect the fragile mountainous area, which claimed that if the slope of the farmland was higher than 25 degree, it should be converted into grassland or forestland. This paper provides a basis for the strategy of converting farmland into grassland or forestland. That is, if the slope of the farmland was higher than 25 degree and its output was higher than the regional average, it should be withheld; if the slope of the farmland was higher than 25 degree, and its output was low than the regional average, it should be converted.