【作者】 甄江红；

【导师】 刘果厚；

【作者基本信息】 内蒙古农业大学 ， 水土保持与荒漠化防治， 2008， 博士

【摘要】 四合木为鄂尔多斯高原所特有的蒺藜科单种属植物,因起源古老、抗逆性强,并为生物多样性起源和环境演变研究的理想对象,四合木具有重要的学术研究价值且倍受关注。但近年来四合木分布区生态环境与景观格局发生了显著变化,原有植被自然景观破碎化明显,生境岛屿化现象普遍,致使其种群数量锐减,处于濒危状态。为此,本文即以四合木为研究对象,以其分布范围为研究区域,以四合木分布区内不同的种群斑块为生境单元,借助1977、1990、2000与2005年4个时期陆地卫星遥感影像,运用3S技术,在分析四合木种群面积动态变化的基础上,探讨其生境景观格局时空演变特征及其影响因子与作用份额;通过不同生境四合木种群数量与结构特征的比较研究,分析四合木对生境适应性的空间差异及生境与景观格局变化对其种群动态的影响;在深入分析四合木生境需求的基础上,确定影响其生存的主要生态因子及其代用指标,并用评价模型进行生境适宜性评价。主要结论如下:1.四合木主要分布在黄河与桌子山之间的狭长地带上,分布区总面积2824.31km2,由8个种群斑块组成。在研究时段内其种群面积不断减少,28a年间减少了19.36%,年均减少13.40km2;但在不同时空尺度上的减少速率并不相同。其中,以1990~2000年间减少得最快,1977~1990年间减少得最慢,且其年减少率有逐年增大趋势;在空间分布上四合木面积以桃司兔种群减少得最多,低山种群减少得最少;千里山种群减少速率最大,乌家庙种群减少速率最小。2.四合木是研究区的基质景观,但1977年以来其生境景观格局发生了较大变化。在整个景观中,斑块数量、斑块密度、景观形状指数及多样性与均匀性指数不断增加,而斑块平均面积与优势度指数逐年减小,表明研究区的景观组分趋于复杂化、破碎化与多元化。各生境类型区中,以石嘴山、桃司兔、千里山与乌达种群的景观格局较为破碎,景观结构趋于复杂;乌家庙、棋盘井与海南种群的景观格局较为完整,景观中有连通度极高的优势斑块类型存在。在各种景观中,四合木是研究区最大的景观组分,但研究时段内其主导地位不断下降,空间分布趋于分散、破碎;而耕地与林地、城镇与居民点、工矿、沙化土地及其它植被面积大幅增长,有连片延续发展且在景观中的作用与影响程度逐渐加大趋势。3.研究区历年气候波动和人类活动变化的代用指标分析表明,20世纪70年代以来,四合木分布区旱化趋势加剧,水分亏缺严重,加之人口数量剧增及城市化与工业化的巨大压力,使四合木的生存环境面临更为严峻的考验。各因素对四合木生境影响的累加效应分析表明,自然因素与四合木种群面积的关联程度大多以4a左右的平均尺度最高,人为因素的关联程度大多以6a左右的尺度最高,具有在时间尺度及累加作用上大于气候条件变化的特点。从主成分因子的信息贡献来看,人为因素对四合木生境影响作用的贡献率为55.66%,自然因素的贡献率为44.34%,可见人为因素的作用是导致四合木生境劣化的主要原因。4.不同生境的四合木种群数量与结构特征有所不同,表明四合木对不同生境的适应性有一定差异。其中四合木密度与多度以海南、低山种群较高,棋盘井与乌达种群较低;盖度、高度、冠幅以低山、乌家庙种群较大,乌达、千里山种群较小;重要值和综合优势比以低山、乌家庙、棋盘井种群较高,乌达与千里山种群较低;不同生境中四合木种群的径级、龄级、冠幅、高度结构亦有差别,体现出低山、乌家庙、棋盘井种群中四合木的适应性较高,而乌达与千里山种群中其适应性相对较低的特点。5.四合木生境适宜性的定量评价与分析表明,研究区内的气候与地形等自然因素不是四合木生长及濒危的限制性因素;而人类活动的干扰使其较不适宜或不适宜的生境面积增加了1.42%,且有33.71km2的可生存生境退化为较不适宜生境,说明人为活动可能是导致四合木局部濒危的关键因素。在各生境类型区内,以乌家庙、低山、棋盘井种群的生境质量较好,而乌达与千里山种群的生境质量较差。更多还原

【Abstract】 Tetraena mongolica Maxim.,which is only found to be very xerophytic and gregarious on sandish grassland in Western Ordos Plateau of Inner Mongolia,belongs to a endangered relic plant species of Zygophyllaceae.Because of origin antiquity,strong resistance and an ideal object to study the origin of biology diversification and evolution of environment,T. mongolica has important academic research value and to be attentioned widely.But in recent years,the entironment and landscape pattern in the distribution region of T. mongolica has taken place remarkable changes.The primary plants landscape pattern has been fragmented and the habitat was islanding.So the population area of T. mongolica has been declining and the plant species has fallen into severe endangered.The paper took T. mongolica as an research object,took the distribution region of T. mongolica as research area,took the different population patches of T. mongolica as habitat units,and 4 sensing images of T. mongolica’s distribution region in different period(s1977、1990、2000、2005)and the technology of remote sensing,geographical information system and global positioning system was used to analyze the temporal and spatial changes characteristic of landscape pattern and the effect factors and their function shares based on the dynamic changes analysis of T. mongolica population areas. Through a comparative study of quantitative and structure characteristics of T. mongolica populations in different habitats,the paper analyzed the spatial difference of T. mongolica’s adaptability to different habitats and the effects of habitats or landscape pattern changes on population’s dynamic.Based on the analysis of T. mongolica’s habitat needs,the paper set up the main ecological factors which affect T. mongolica’s survival and selected their substitutive indexes. The habitat suitability of T. mongolica was assessed based on the habitat evaluation procedure. The results showed:1.T. mongolica is mainly distributed in the narrow region between Yellow River and Zhuozi Mountain,and the distribution area is 2824.31km2,it is composed of 8 populations. The population area of T. mongolica has been decreasing in the research period,It had decreased 19.36% and 13.40km2/a during 28 years. But the decreasing speed of T. mongolica population area is varied in different temporal and spatial scale,the annual decrease rate is most during 1990-2000,and it is least during 1977-1990.And the annual rate of decreasing is in an increasing trend year after year. On the spatial scale,the decreasing area is most in Taositu population and least in Dishan population,the annual decrease rate is most in Qianlishan population and least in Wujiamiao population.2.T. mongolica is the basic landscape type in the research region,but the landscape pattern of its habitat has been changed largely from 1977. On landscape scale,Patch number,Patch density,Landscape shape index,Shannon’s diversity index and Shannon’s evenness index increased,while Mean patch size and Dominance index decreased year after year. It indicated that the landscape pattern tend to be complicated,fragmented and poly_basic in the distribution region of T. mongolica. In the different habitats of T. mongolica,the landscape patterns in Shizuishan,Taositu,Qianlishan and Wuda populations were fragmented. The landscape structure tend to be diversification and complicated.While the landscape patterns in Wujiamiao,Qipanjing and Hainan populations were integritied relatively and there were preponderant patches which connected each other in the landscape. In the all of landscape types,T. mongolica was the maximal landscape component in the research region,but its dominant status reduced in period of 28 years and its distribution tend to be dispersed and fragmented. While the farming land,town and industry land,desertification land and else vegetations increased largely and tend to be connectd. Their effects on landscape were increasing gradually.3.The substitutive indexes of climate fluctuation and human activities changes in the research region were analyzed. It indicated that the trend of drought and the lack of rain has been severed from 1977 in the distribution region of T. mongolica. And with the population increasing and development of industry and fast urbanization,the survival entironment of T. mongolica is more severe. The cumulative impact of driving force of T. mongolica’s habitat was analyzed and the results show that the accumulative impact of natural factors came to the maximum in the fourth year,while the accumulative impact of human activities was the most significant in the sixth year. The impacts of human activities on T. mongolica’s habitat was in a longer time period and more significant than the natural factors. From the contribution of the information of principal components,the ratio of the contribution of human activities was 55.66%,the contribution of natural factors was 44.34%. Therefore,human activities was the main reasons for T.mongolic’s habitat deteriorating.4.The quantitative and structure characteristics of T. mongolica population in different habitats were difference. It indicated that T. mongolica’s adaptability to different habitats were different. The density and abundance were higher in populations of Hainan and Dishan,but they were lower in populations of Qipanjing and Wuda.The coverage,height and crown breadth were higher in populations of Dishan and Wujiamiao,but they were lower in populations of Wuda and Qianlishan. The conspicuousness and summed domimamce ratio were higher in populations of Dishan,Wujiamiao and Qipanjing,but they were lower in populations of Wuda and Qianlishan. The diameter-class,age-class,width-class and height-class structure of T. mongolica populations were different in different habitats,it indicates that T. mongolica’s adaptability to habitats were higher in the populations of Dishan,Wujiamiao and Qipanjing,and they were lower in population of Wuda and Qianlishan.5.Habitat suitability of T. mongolica was assessed. It indicated that climate and terrain in the research region were not restrictive factors to survival and endanger of T. mongolica. While human activities made the less suitable habitat and unsuitable habitat increased by 1.42%,and the area which the survival habitat degenerate to less suitable habitat was 33.71km2. It showed human activities may be the key factor result in part endanger of T. mongolica. In the different habitats,the habitats quality were higher in populations of Wujiamiao,Dishan and Qipanjing,and they were lower in the populations of Wuda and Qianlishan.更多还原