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1.
放牧对古尔班通古特沙漠南部 沙垄地表性质的影响 总被引：2，自引：0，他引：2
分别于2002 年和2005 年对古尔班通古特沙漠南部的同一条半固定沙垄, 进行了放牧前后的地表覆盖(包括植物和生物结皮)、沙面活动强度和土壤理化性质的系统监测和研究。 主要结论如下: 2002 年, 自然沙垄80%以上的地表被植物和生物结皮所覆盖, 除沙垄顶部外, 其他部位基本处于稳定状态。2005 年受放牧干扰的影响, 生物结皮破损率达到80%以上, 同期植物覆盖不及2002 年的1/5, 特别是短命植物变化最明显。2005 年输沙势只有2002 年的1/3, 但沙面活动强度是2002 年的2.6 倍, 活动区域也从垄顶部扩展至整个沙垄表面。 放牧后地表组成物中的中沙含量增加了13.9%, 而细沙和极细沙含量分别减少了7.4%和 8.0%, 沙垄各部位有机质含量在放牧后一个风季即下降了近1/2。可见, 放牧造成地表保护条件的多重损害, 使沙漠地表稳定性趋于丧失。其细粒物质及有机质的大量流失, 也将对我国温带荒漠生态系统的可持续发展产生重要影响。 相似文献
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古尔班通古特沙漠生物结皮小尺度分异的环境特征 总被引：12，自引：5，他引：7
古尔班通古特沙漠广泛存在的生物结皮,对地貌部位有极强的选择性分布,其实质是生物对环境条件综合适应的一种生态表现。2002年3~11月在个体沙丘表面初步开展了生物结皮类型小尺度环境分异规律研究。结果表明:苔藓结皮、地衣结皮和藻类结皮依次分布于垄间、沙垄两坡中部和坡上部,从垄间往垄顶,生物结皮盖度逐渐减小,厚度变薄,抗压性减弱。苔藓结皮分布区的物质组成以细沙和极细沙为主,春季表层土壤水分在5%以上,短命植物广泛发育,基质稳定;坡中部的地衣结皮分布区以细沙为主,春季表层土壤水分在4%左右,短命植物亦有广泛分布,地表受风沙活动影响较小;沙垄上部和顶部的藻类结皮分布区,是沙垄表面活动性最强和土壤水分最差的区域,物质组成以中沙为主,高等植物中白梭梭为优势种,可见藻结皮是三类结皮中最能适应恶劣环境的生物结皮类型。 相似文献
3.
春夏季放牧对古尔班通古特沙漠南部土壤种子库和地上植被的影响 总被引：6，自引：5，他引：1
位于新疆北部准噶尔盆地腹地的古尔班通古特沙漠,是世界上温带荒漠生物多样性的精华和最为丰富的典型区域。历史上这里就是北疆羊和部分马匹重要的冬牧场,但近年来的放牧活动在春夏季也开始进入沙漠腹地,使地表性质与植被覆盖发生了明显改变。应用野外随机取样与室内萌发实验相结合的方法,对比研究了古尔班通古特沙漠南部春夏季放牧和冬季放牧沙垄土壤种子库差异及其与地上植被的关系。结果表明：冬季放牧沙垄种子库种数为24种,而春夏季放牧沙垄有20种,后者明显减少了植物种数。冬季放牧沙垄种子库密度为(353.2±87)粒·m-2,而春夏季放牧沙垄为(189.1±23)粒·m-2,比前者减少了88%。两类沙垄土壤种子库的生活型组成都以一年生植物为主,相似性系数为0.711。相同沙垄不同部位的物种相似性系数在0.429～0.600之间,异质性较大,尤其表现在除垄顶之外的其他部位。冬季放牧沙垄和春夏季放牧沙垄地上植被中分别有植物36种和26种,各生活型所有物种均为后者低于前者,其中短命、类短命物种数量减少幅度最大。春夏季放牧沙垄地上植被的物种多样性和均匀度降低,而优势度升高。回归分析显示,冬季放牧沙垄定植群落有21%的变异来源于土壤种子库,而春夏季放牧沙垄有51%的变异来源于土壤种子库,可见不同季节的放牧干扰显著影响土壤种子库及其与地上植被的相关关系。 相似文献
4.
古尔班通古特沙漠腹地半固定沙垄顶部风沙运动规律 总被引：7，自引：2，他引：5
利用DETI可移动测风系统,结合多向集沙、阶梯式积沙和总体沙面活动强度观测,系统研究了古尔班通古特沙漠腹地半固定沙垄表面风沙运动规律。结果表明:沙漠腹地沙垄两坡和垄间多被植被与生物结皮覆盖,地表处于稳定状态,地表输沙主要集中于垄顶部至两坡上部。系统性天气条件下,气流以净风状态在迎风坡持续加速,至垄顶迎风侧边缘流速增至最大并开始起沙,风沙流越过垄顶后受植被阻挡和回旋涡流的双重影响,在垄顶背风侧上部急剧减速并发生沙物质沉积,此后气流速度又逐渐恢复。起沙风由沙垄两侧交替入射,不断将沙物质从垄顶一侧搬运到另一侧。流动带两侧沙面活动剧烈,流动带中部作为过沙床面,蚀积变化低于两侧。垄顶输沙量沿垂线方向呈指数分布,输沙率、各高度层输沙量以及沙物质输移高度都随着风速的增大而增大。垄顶部距地表6 cm和10 cm以内的输沙量分别占总输沙量的80%和90%。垄顶输沙势与实测输沙量之间具有良好的相关性,初步推测1VU的输沙风能在垄顶1 m的过沙宽度上可以产生25 kg的输沙。 相似文献
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6.
古尔班通古特沙漠腹地春季土壤水分空间分异研究 总被引：18，自引：7，他引：18
土壤水分条件是古尔班通古特沙漠荒漠植被发育的最主要的制约因子，春季土壤水分对该区植被发育更具决定作用。通过野外标定，利用中子水分仪对原始沙丘、工程扰动沙丘不同地貌部位土壤水分动态进行系统监测，结果表明：春季土壤水分受地貌部位和人为干扰等因素影响而出现明显的空间分异，整体表现为垄间低地高于垄顶，人为扰动沙面又高于有植被覆盖的沙面。春季土壤水分的时间变化表现为初春(3—4月)土壤水分的补给期和春末夏初(5—6月初)的土壤水分损耗期。认为植被状况、降雨、地形和人为扰动等因素对土壤水分影响较大。 相似文献
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污泥沙障对流动沙区植被恢复的作用 总被引：1，自引：0，他引：1
利用城市生活污水处理厂脱水污泥制成成本低、吸水保湿性强和环境友好的污泥方格沙障、沙面上污泥平板沙障和沙面下污泥平板沙障,用于帮助恢复生态极端恶劣的流动沙区植被。调查撒播黄蒿（Artemisia scopara ）种子后试验区沙丘植物的种类、覆盖度、生长状况等植被恢复指标。结果表明：污泥沙障处理下,人工播种的黄蒿、天然的沙米（Agriophyllum squarrosum ）盖度、高度（除沙米）和生物量均显著高于裸沙区（对照）（p <0.05）,雾滨藜（Bassia dasyphylla ）、碱蓬（Suaeda glauca ）和猪毛菜（Salsola ollina ）的盖度、高度、多度、生物量（除雾滨藜）均高于对照;污泥方格沙障区的植物物种丰富度最高,沙面上污泥平板沙障区次之,沙面下污泥平板沙障及对照区较小;Shannon-Wiener多样性指数和Simpson多样性指数均为污泥方格沙障>沙面上污泥平板沙障>沙面下污泥平板沙障>对照;Pielou均匀度指数为污泥方格沙障>沙面下污泥平板沙障>沙面上污泥平板沙障>对照。综合考虑混合污泥成本、用量、植被恢复效果等诸因素,我们推荐采取污泥方格沙障治沙措施,使其在沙地植被恢复工作中发挥作用。 相似文献
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古尔班通古特沙漠风沙活动特征与线形工程安全研究 总被引：9，自引：7，他引：9
古尔班通古特沙漠是我国第二大沙漠，沙丘类型以固定和半固定纵向沙垄为主。垄间和坡中下部沙面较为稳定，仅在沙垄顶部存在10—40m宽度不等的流动带，风沙活动规律独特。近年来在沙漠腹地修筑的公路、引水渠等线形工程，不可避免地造成沙垄切剖和保护层破环，所引发的工程安全问题引起了人们的普遍关注。通过风况分析和实地观测，对沙漠腹地风沙活动特征进行了初步研究，同时对线形工程风沙危害进行监测，在此基础上提出现有防护体系存在的主要问题与对策。 相似文献
9.
古尔班通古特沙漠纵向沙垄植被空间异质性 总被引：5，自引：3，他引：2
在古尔班通古特沙漠南部纵向沙垄上按5 m×10 m的网格测度植被样方100个,采集浅层风沙土样品184件。调查发现,乔灌木层片和草本层片的分布及相互关系明显受沙垄地形影响,并且在干旱环境下种群间的竞争和空间上的互补使两层片生态优势度具有显著的相关性。地统计分析结果显示,纵向沙垄上植被空间异质性表现为木本层片的物种多样性呈斑块状分布,草本层片物种多样性呈现平行沙垄的带状结构和斑块结构叠加的特点,而植被盖度则在垂直沙垄走向的方向上具有强烈的梯度性变化。和沙垄土壤理化性质空间格局特征相对比,植被盖度及物种多样性与风沙土浅层含水量在自相关空间（变程）及空间异质性程度上比较接近。这是纵向沙垄小生态系统中草本植物和浅层土壤水分耦合关系在空间上的反映,也是木本植物对水分和土壤资源在小尺度（m）上竞争及中小尺度（10～100 m）上互补的结果。 相似文献
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尾矿砂沙害形成机理与工程治理措施的选择 总被引：1，自引：0，他引：1
尾矿砂沙害的形成过程,包含着尾矿砂强烈风蚀、尾矿砂输送搬运与堆积,以及尾矿砂吹扬在大气中的粉沙悬移等3个过程。上述3个过程对土地、大气、水体、道路、建筑物及农作物造成严重危害,甚至影响人身健康。研究结果表明,尾矿砂的治理,需采用固结沙面、切断沙源,即消除灾害源的方法。固结沙面的材料,宜采用坚固耐久、抗风蚀力强、具有较好蓄水保墒性能,以及保温能力高、且廉价的戈壁沙砾石。沙砾石覆盖之后,不仅固结了沙面,切断了沙源,而且为天然植物种子的散落和幼苗发育创造了稳定条件,加快了天然植物衍生。覆盖后的第一年雨季后,植物盖度到达了15%~30%,局部地段高达50%。 相似文献
11.
Based on systematically monitoring plants on dune ridges in the southern part of the Gurbantunggut Desert in 2002, this paper, from the angle of dune stabilization by vegetation, describes the temporal and spatial distribution patterns of ephemeral plants on isolated sand dunes, analyses the natural invasion processes of ephemeral plants on human-disturbed sand surface and expounds the importance of ephemeral plants in stabilizing sand dune surface. A total of 45 plant species were identified in the study area, 29 of which are ephemeral plants. Ephemeral plants sprouted in early April and completed their life-circle within about two months. Just as aeolian sand activities came to the strongest stage from April to June in desert regions of northern Xinjiang, the total coverage of trees, shrubs and herbs of long vegetational period on most dune ridges was less than 10%, while the mean coverage of ephemeral plants reached 13.9% in April, 40.2% in May and 14.1% in June. Therefore ephemeral plants acted as the major contributor to dune surface stabilization in the Gurbantunggut Desert. Investigations of vegetation restoration on engineering-disturbed dune surface show that ephemeral plants first recolonized the disturbed dune surface. 相似文献
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古尔班通古特沙漠短命植物分布及其沙面稳定意义 总被引：7，自引：3，他引：4
Based on systematically monitoring plants on dune ridges in the southern part of the Gurbantunggut Desert in 2002, this paper, from the angle of dune stabilization by vegetation,describes the temporal and spatial distribution patterns of ephemeral plants on isolated sand dunes,analyses the natural invasion processes of ephemeral plants on human-disturbed sand surface and expounds the importance of ephemeral plants in stabilizing sand dune surface. A total of 45 plant species were identified in the study area, 29 of which are ephemeral plants. Ephemeral plants sprouted in early April and completed their life-circle within about two months. Just as aeolian sand activities came to the strongest stage from April to June in desert regions of northern Xinjiang, the total coverage of trees, shrubs and herbs of long vegetational period on most dune ridges was less than 10%, while the mean coverage of ephemeral plants reached 13.9% in April, 40.2% in May and 14.1% in June. Therefore ephemeral plants acted as the major contributor to dune surface stabilization in the Gurbantunggut Desert.Investigations of vegetation restoration on engineering-disturbed dune surface show that ephemeral plants first recolonized the disturbed dune surface. 相似文献
13.
古尔班通古特沙漠地区短命植物土壤种子库研究 总被引：12，自引：0，他引：12
采用野外定点取样和室内萌发相结合的试验方法,研究了短命植物在沙丘不同部位的空间分布、萌发状况、密度、物种多样性及土壤种子库生物多样性与地上植物多样性的关系。结果表明:短命植物种子主要集中分布于地表0~5 cm土壤中,5 cm以下土壤中极少存在有活力的种子;沙丘间及沙丘不同部位的种子库密度大小不同,密度自坡底随高度增加逐渐减少,坡底、坡中部及坡顶部密度分别为124粒/m2、91粒/m2、66粒/m2。迎风坡种子库密度比背风坡面少,迎风坡种子库平均密度为81粒/m2,而背风坡种子库平均密度为100粒/m2;短命植物种子在4月上旬达到萌发高峰,沙丘不同部位物种多样性存在差异,土壤种子库和地上植被存在较高的相似性,此外短命植物在沙丘不同部位的分布存在较高的空间异质性。 相似文献
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春季积雪融水是古尔班通古特沙漠土壤水分的重要补给源之一,为早春植物的萌发和生长创造了有利的条件。为掌握该地区春季沙丘的土壤水分分布状况,采用探地雷达测量技术,于2010年4月进行了多次野外测量,并通过对地面直达波信号的提取和分析,初步获得了一致的测量结果。结果表明：（1）探地雷达地面直达波测量的土壤平均含水量与20 cm深同步TDR的测量结果非常接近,两者总体相差在0.02 cm3/cm3以内,充分反映了GPR地面直达波测量结果的有效性和精确性;（2）春季积雪完全融化后,沙丘/沙垄顶部土壤水分明显低于垄间低地,这与前人的研究一致,反映了积雪和冻土层在消融过程中,沙丘表面融水在坡面重力作用下,沿难以透水的冻土层上界自坡上向坡下迁移,形成了垄间最高、坡部次之和垄顶最少的分布格局;（3）垄间低地的土壤水分明显受到低矮灌草丛的影响进行再分布,这是由于积雪最初沿植丛基部开始消融,并以植丛为中心形成漏斗状融洞,从而形成以植丛为中心汇集较多融雪水的格局,而垄间低地中较为高大的梭梭乔木对融雪水的再分布影响明显不如低矮的灌草丛,这与其地表茎基过少有关。此外,探地雷达测量实验提供了详实可靠的表层土壤含水量分布信息,可为荒漠生态系统的空间尺度研究提供真实可靠的数据基础。 相似文献
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放牧对古尔班通古特沙漠南部半固定沙垄地表性质的影响 总被引：1，自引：0，他引：1
Intensive grazing in spring-summer has been responsible for environmental deg- radation of the Gurbantunggut Desert in recent years. The coverage of plants and biological crusts, sand surface stability and physicochemical characteristics of soil on the dune surface were conducted in 2002 (winter grazing) and 2005 (spring-summer grazing). The results showed that over 80% of the total area of the dune surface was covered by well-developed biological crusts and plants in 2002, when the interdune and middle to lower part of dune slopes were stabilized and only the crest had 10-40 m wide mobile belt. Affected by spring-summer grazing in 2005, over 80% of the total cover of biological crust was destructed and the plant coverage only reached 1/5 of that in 2002, especially the ephemeral plant cover had a great change. The value of sand transport potential in 2005 only reached 1/3 of that in 2002, but the total surface activity in 2005 was 1.6 times stronger than that in 2002. Mean- while the mobile area began to expand from the dune top to the whole dune surface following spring-summer grazing. Compared with 2002, medium sand content of the dune surface soil increased by 13.9%, while that of fine and very fine sands decreased by 7.4% and 8.0% re- spectively in 2005 and the soil organic matter in 2005 was only about 1/2 of that in 2002. It is obvious that the presence of snow cover and frozen soil in winter could avoid the surface structure destruction in winter, while spring--summer grazing made excessive damage to biologic crusts and ephemeral plants. Spring is the main windy season in Gurbantunggut Desert and therefore intensive activity of dune surface occurred following spring-summer grazing, which led to a great loss of fine sand and organic matter. It can be seen that grazing season have a significant influence on the sustainable development of the desert ecosystem in Northwest China. 相似文献
16.
Intensive grazing in spring–summer has been responsible for environmental degradation of the Gurbantunggut Desert in recent years. The coverage of plants and biological crusts, sand surface stability and physicochemical characteristics of soil on the dune surface were conducted in 2002 (winter grazing) and 2005 (spring–summer grazing). The results showed that over 80% of the total area of the dune surface was covered by well-developed biological crusts and plants in 2002, when the interdune and middle to lower part of dune slopes were stabilized and only the crest had 10–40 m wide mobile belt. Affected by spring–summer grazing in 2005, over 80% of the total cover of biological crust was destructed and the plant coverage only reached 1/5 of that in 2002, especially the ephemeral plant cover had a great change. The value of sand transport potential in 2005 only reached 1/3 of that in 2002, but the total surface activity in 2005 was 1.6 times stronger than that in 2002. Meanwhile the mobile area began to expand from the dune top to the whole dune surface following spring–summer grazing. Compared with 2002, medium sand content of the dune surface soil increased by 13.9%, while that of fine and very fine sands decreased by 7.4% and 8.0% respectively in 2005 and the soil organic matter in 2005 was only about 1/2 of that in 2002. It is obvious that the presence of snow cover and frozen soil in winter could avoid the surface structure destruction in winter, while spring–summer grazing made excessive damage to biologic crusts and ephemeral plants. Spring is the main windy season in Gurbantunggut Desert and therefore intensive activity of dune surface occurred following spring–summer grazing, which led to a great loss of fine sand and organic matter. It can be seen that grazing season have a significant influence on the sustainable development of the desert ecosystem in Northwest China. 相似文献
17.
Vegetation and soil surveys were conducted under different site conditions in 2007–2011 to study species diversity using richness, evenness and diversity indices, in the middle portion of the Heihe River Basin. The relationship between species distribution and soil environmental factors was also studied by Canonical Correspondence Analysis (CCA). Results show that vegetation coverage and species diversity were the highest in the interdune lowland, and the lowest in the mobile dune. Results of the Hill’s index (diversity ordering) shows that species diversity is reduced along decreasing soil water content, and the order of species diversity was interdune lowland, flat slope, fixed dune, semifixed dune and mobile dune. The influence degree of soil factors on vegetation distribution was soil water content > pH > total K > organic matter > available N > total N > available K > total P > saline content > available P. Soil water content and pH were important factors significantly affecting spatial distribution difference of vegetation, the environmental explanation was 98%. 相似文献