KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 近30年埃塞俄比亚低海拔区草地灌丛化过程特征 | |
| 邢媛媛 | |
| Subtype | 硕士 |
| Thesis Advisor | 雷加强 |
| 2017-05-01 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 新疆乌鲁木齐 |
| Degree Discipline | 农学硕士 |
| Keyword | 埃塞俄比亚低海拔区 灌丛化草地 土壤理化性质 单一土地利用动态度 土地利用变化重要性指数 The lowland of Ethiopia Bush encroachment Soil physical and chemical properties A single land use dynamic degree The land use change significant index |
| Abstract | Based on the understanding of characteristics difference of bush encroachment indifferent level, taking bush encroachment as research objective, in lowland of Ethiopia,and by remote sensing interpretation and classification, field survey and laboratoryanalysis, this paper studied the different of vegetation characteristics and soil physicaland chemical properties in different grade of bush encroachment, then by countingindexes of a single land use dynamic degree and the land use change significant indexanalyzed time and space change and land use change type in the Lowland of Ethiopiaduring the Past 30 Years. Results showed that:(1) The appearance change of herbaceous plants extremely obvious of differentgrades of bush encroachment in study area. With a deeper bush encroachment, the totalcoverage of herbaceous plants, the coverage of dominant species, above-groundbiomass declined sharply, and average height significantly reduced. The total coverageof herbaceous plants, the coverage of dominant species, above-ground biomass weresignificantly different among slight, moderate and severe bush encroachment. There aremany kinds of dominant species in severe bush encroachment, and which mostly weregrasses and high satisfaction level. So severe bush encroachment keep highest speciesrichness than slight and moderate bush encroachment.(2) There were remarkable differences on soil physical properties in differentgrades of bush encroachment. Soil moisture content is highest in moderate bushencroachment, and increased with the increase of soil depth in moderate and severebush encroachment; Soil volume weight is highest in slight bush encroachment andlowest in moderate bush encroachment; soil density showed moderate < severe < slightbush encroachment; in aspect of soil mechanical composition, the clay is slightlydifferent in different grades, and had no significant difference change over soil layers.(3) There were remarkable differences on soil chemical properties in differentgrades of bush encroachment. The pH and electric conductivity content in moderate bush encroachment were significantly higher than slight and severe bush encroachment.The organic matter content, total N content and total P content first increased and thendecreased with bush encroachment degree, the organic matter content was significantdifferences between moderate and slight bush encroachment, the total N content wasno significant differences among three degree bush encroachment, the total P contentwas significant differences among three degree bush encroachment; the total K contentfirst decreased and then increased with bush encroachment degree and was significantdifferences between moderate and slight bush encroachment. The inorganic nitrogencontent increased with bush encroachment degree, and was no significant differencesamong three degree bush encroachment; the available P content was highest inmoderate bush encroachment, then was severe bush encroachment, last is slight bushencroachment, and was significant differences among three degree bush encroachment;the available K content decreased with bush encroachment degree, and was nodifference between slight and moderate bush encroachment.(4) In 1986-2016 year, the extent of variation of total grassland area was no big,and highest was 4282.31km2in 2003 year; the bush encroachment area was an upwardtrend, and the highest was 3742.49 km2in 2003 year, and when the severe bushencroachment was 2664.17 km2and was highest; the grassland area was an downwardtrend, and the highest was 1210.87 km2in 1986 year, and it was a slight increase in2003-2016 year. In addition, in 1986-2016 year, the average annual change rate ofwoodland, other and grassland were negative, bush encroachment was positive; theaverage annual change rate of the other rapidly declined and which was -1.47%, thenwas grassland, which was -1.12%; the average annual change rate of the slight bushencroachment rapidly increased and which was 1.24%, then was severe bushencroachment, which was 0.96%.(5) The change area of land use was 3099.09 km2, accounting for 57.12% of studyarea. In 30kinds of land-use change, woodland shifted in severe bush encroachment,moderate bush encroachment shifted in severe bush encroachment, severe bushencroachment shifted in other, grassland shifted in severe bush encroachment, severe bush encroachment shifted in moderate bush encroachment, grassland shifted inmoderate bush encroachment, those,12 kinds of land-use change, were main shiftdirection. Woodland shifted in severe bush encroachment, moderate bush encroachmentshifted in severe bush encroachment, severe bush encroachment shifted in other,grassland shifted in severe bush encroachment were main change species, and changearea was bigger, accounting for 8.56%, 5.82%, 5.23% and 5.22% of total change area.In total, woodland and grassland mainly converted to bush encroachment, and the areaof bush encroachment has increased. |
| Other Abstract | 本文以埃塞俄比亚低海拔区灌丛化草地为研究对象，结合遥感解译、实地调查与实验室分析等多种分析方法，以空间代替时间，在对灌丛化草地分级基础上，探讨了不同程度灌丛化草地植被特征与土壤理化性质变异特征，通过计算单一土地利用动态度与土地利用变化重要性指数等指标分析了研究区近 30 年灌丛化草地时空变化与土地利用变化类型。结果表明：（1）研究区内不同程度灌丛化草地草本植物在群落结构变化上极其显著。随灌丛化程度加重，草地草本植物总盖度、建群种盖度、地上生物量及植物平均高度急剧下降。其中，轻度灌丛化、中度灌丛化、重度灌丛化草地的草本植物的总盖度、建群种盖度、地上生物量呈显著差异。重度灌丛化区建群种植物种类较多，且多为禾本科植物，是牲畜满意度较高、喜食的牧草。（2）不同程度灌丛化草地土壤物理性质差异显著。土壤水分特征表现为中度灌丛化草地最高，重度和中度灌丛化草地都出现随土壤深度增加，土壤含水量增加的现象；容重表现为中度灌丛化最低，而轻度灌丛化草地土壤容重最大；土壤紧实度与表层（0-5cm）土壤容重规律一致，即中度＜重度＜轻度灌丛化草地；从土壤机械组成来看，各等级灌丛化草地黏粒含量差别不大，差异不显著，随土层变化差异也不显著。（3）不同程度灌丛化草地土壤化学性质差异显著。中度灌丛化草地土壤的pH 值和电导率显著高于轻度和重度灌丛化草地。灌丛化草地土壤的有机质、全N 和全 P 含量随灌丛化程度的加深表现出先增大后减小的趋势，中度灌丛化草地土壤中有机质含量与轻度灌丛化差异显著，全 N 含量与轻度和重度灌丛化差异不显著，全 P 含量与轻度和重度灌丛化差异均显著；全 K 含量随灌丛化程度的加深表现出先减小后增大的趋势，轻度灌丛化草地土壤中含量最高，仅与中度灌丛化差异显著；土壤的无机氮含量随灌丛化程度的加深表现出增加的趋势，重度灌丛化草地土壤中含量最高，但与中度和轻度灌丛化差异不显著；速效 P 在中度灌丛化草地土壤中含量最高，重度灌丛化其次，轻度灌丛化最低，且相互差异显著；速效 K 含量随灌丛化程度的加深表现出下降的趋势，轻度与中度灌丛化草地差别不大，较重度灌丛化草地差异也不显著。（4）1986～2016 年，总草地面积变化幅度不大，2003 年达最大，为 4282.31km2；灌丛化草地面积整体呈上升趋势，在 2003 年达最大，为 3742.49 km2，其中重度灌丛化草地面积也达最大，为 2664.17 km2；2003 年至 2016 年有小幅下降；草地面积整体呈下降趋势，在 1986 年面积最大，为 1210.87 km2，仅 2003 年至 2016 年有小幅上升；1986～2016 年 30 年的各土地类型的年均变化率中，林地、其它和草地的变化速率为负，灌丛化草地的为正，包括轻度、中度和重度灌丛化草地；其中，其它类型的减少速度最快，为-1.47%，其次是草地，为-1.12%；轻度灌丛化草地的增加速度最快，为 1.24%，其次是重度灌丛化草地，为 0.96%。（5）研究区土地利用变化面积 3099.09 km2，占总面积的 57.12%；发生的 30种土地类型变化中，林地转重度灌丛化草地、中度转重度灌丛化草地、重度灌丛化草地转其它、草地转重度灌丛化草地、重度转中度灌丛化草地、草地转中度灌丛化草地等 12 类土地变化是土地利用变化的主要方向；其中土地类型变化过程中，林地向重度灌丛化草地转化，中度向重度灌丛化草地转化，重度灌丛化草地向其它类型转化和草地向重度灌丛化草地转化的面积较大，所占比例较高，分别为 8.56%、5.82%、5.23%和 5.22%，是土地类型变化的最主要的类型；总体来说，林地和草地多是向灌丛化草地转化，灌丛化草地面积有所增加。 |
| Subject Area | 水土保持与荒漠化防治 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/14908 |
| Collection | 研究系统_荒漠环境研究室 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 邢媛媛. 近30年埃塞俄比亚低海拔区草地灌丛化过程特征[D]. 新疆乌鲁木齐. 中国科学院大学,2017. |
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