濒危植物四合木生境景观动态及其驱动因子分析

以1977 年MSS 及1990 年、2000 年、2005 年TM 影像数据为基本信息源，运用RS 与GIS 技术，选择若干相 关指标，在系统分析四合木生境景观构成动态变化及其自然与人文驱动因子变化特征的基础上，采用主成分分析 法进行了四合木生境景观动态驱动因子作用强度及其贡献率的定量分析。结果表明：28 年来四合木分布区景观构 成变化较大，其中四合木种群面积不断减少而耕地、城镇、工矿等人工景观类型不断扩张，沙地与其他植被面积扩 展明显，这与研究区旱化趋势加重、人为干扰强度加剧密切相关，且人为因素是造成四合木种群大面积减少及其生 境景观格局变化的主要外因。

Landscape Dynamics and Driving Factors of Endangered Plant Tetraene mongolica's Habitats

Using technology of remote sensing and geographical information system,the paper analyzed four remote sensing images of Tetraena mongolica distribution area in different periods(1977,1990,2000,2005)to study the dynamic changes of landscape composition in the study area.Through some substitutive indexes of climate fluctuation and human activities,the paper analyzed the variation characteristic of driving factors on landscape dynamics at time scale.On this basis,the method of Principal Component was applied to analyze the influence and the contribution rate of different factors to landscape dynamics of T.mongolica's habitats.The results showed that the landscape composition of T.mongolica's habitat has been changed largely and the population inhabited area of T.mongolica has been decreasing while farmland,urban and industrial land,desertified land and else vegetations increased largely.The temperature,the mean wind velocity and the gale days had a process of rising continuously while the precipitation in the distribution region of T.mongolica had a process of reducing from the 1980s.The disadvantageous change of climate had a disadvantageous impact on T.mongolica's growth and reproduction.Meanwhile,with population growth,industrial development and rapid urbanization,the survival entironment of T.mongolica becomes more serious.There were consanguineous relationship between the dynamic changes of landscape composition and the trend of drought and human activities.From the contribution of the information of Principal Components,the contribution rate of human activities was 55.66%,and that of natural factors was 44.34%.Therefore,human activities were the main reasons for the decrease of T.mongolica population area and the changes of landscape structure in its habitat.