呼伦贝尔森林-草原交错区景观格局时空动态

Spatial-temporal landscape dynamics in the Hulunbeir forest-steppe ecotone

基于遥感(RS)与地理信息系统(GIS)相结合的方法,解译并提取了1988年、1995年、2000年和2004年四期呼伦贝尔森林-草原交错区的景观格局空间分布信息,并在Fragstats3.3软件中,分别从景观级别和类型级别出发,分析了该区景观格局的时空动态变化。结果表明:(1)16年来,呼伦贝尔森林-草原交错区各景观类型转换频繁。其中,林地面积减少量最多,达7858.15km2,主要转换为草地;未利用土地面积增加量最多,净增4087.25km2,增加的面积主要来源于草地和林地。(2)景观格局整体波动较大,景观破碎度、景观多样性指数逐年增大,优势度指数降低。(3)受人为干扰的影响,研究区内各主要景观类型均表现出景观斑块由大到小,由少到多,斑块形状复杂化程度增加的特点。(4)主要景观类型质心向东偏移,其中,林地景观的质心向东南方向偏移了50.22°大约4.48km;草地景观整体向东北方向偏移了79.96°大约29.93km。

Describing and understanding spatial patterns over time is an important research arena in landscape ecology. The forest-steppe ecotone with alkalized grassland in Hulanbeir, which borders the Great Xing＇an forest region, is one of the most significant ecological barriers in North China. Since 1950s, the landscape patterns in the ecotone have changed greatly and ecosystem functions have degraded substantially because of excess resource development as well as natural changes. By integrating Remote Sensing （RS） and Geographic Information System （GIS）, this paper explores how and why the landscape pattern changed. The results shows. （ 1 ） it is remarkable to interchange between different landscapes, especially frequently among forest land, grassland, cropland and unused land. The area of forest land has decreased sharply by 7858.15 km^2, while the unused land increased 4087.25 km^2. （2） indices of landscape characteristics have changed significantly from 1988 to 2004, with the landscape diversity index and fragmentation index increasing and the landscape dominance index decreasing. （3） Main landscape types including forest, grassland, cropland, unused land show their patches quantity added and patch shape changed more and more complexly. （4） From 1988 to 2004, the centroid of main landscape types had moved east, the centroid of forest has moved 4.48 km southeast, while the centroid of grassland moved 29.93 km northeast. This study revealed the intensities, directions, and rates of landscape pattern changes, and the relationships among landscape pattern, ecological processes, and human activities. This study can provide scientific basis for the sustainable development of the ecotone.