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对毛乌素沙地南缘不同演化阶段油蒿(Artemisia ordosica)灌丛沙堆进行了调查和统计分析,探讨了演化过程中沙堆形态特征变化及其与灌丛形态间相互关系。结果显示:(1)研究区油蒿灌丛沙堆以发育阶段和稳定阶段主,衰退阶段灌丛沙堆较少。随灌丛沙堆演化,油蒿灌丛高度保持相对稳定,灌丛长轴和沙堆长轴、短轴都显著增大;(2)沙堆的形态参数间存在显著的相关性,其中发育阶段沙堆长轴、短轴和高度之间显著线性相关,且长轴和短轴相对高度增长较快,稳定阶段沙堆3个参数间协同发展到稳定,而衰退阶段沙堆形态参数间相关性下降;(3)除衰退阶段外,沙堆形态参数与灌丛形态参数间有显著的相关关系,其中沙堆长轴与灌丛长轴、沙堆短轴与灌丛短轴、沙堆底面积与灌丛投影面积,均呈显著线性关系。在环境因素作用下,油蒿灌丛沙堆间整体相互协调发展,使其呈现不同形态特征。 相似文献
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干旱地区灌丛沙堆研究现状与展望 总被引：12，自引：1，他引：11
从灌丛沙堆的形成演变、形态特征及其空间格局、表面气流特征及其风蚀堆积平衡、表面植被生态生理特性及其对降水和地下水的响应、土壤理化性质和保育措施等几个方面进行综述。认为目前灌丛沙堆研究只是针对某一区域或多个区域的静态研究,对灌丛沙堆演化过程中的形态、气流、土壤以及植被等因素的变化特征及其相互作用研究不足,难以解释灌丛沙堆的演化机制及其影响因素。同时灌丛沙堆研究过于强调其作为土地退化的指示,而忽略了其在退化生态系统中的重要生态功能,不利于干旱和半干旱区的生态环境恢复。今后的研究应该加强对灌丛沙堆演化过程中的土壤、植被、水分的变化特征及其不同影响因素之间相互作用过程的研究,深入探讨灌丛沙堆在干旱半干旱退化生态系统中的积极作用。基于以上基础数据和理论依据,对灌丛沙堆的保育措施进行探索,找出合理的灌丛沙堆保育措施。 相似文献
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选择位于西风区的新疆艾比湖周边灌丛沙堆为研究对象,利用光释光测年初步建立风沙沉积的时间序列,分析了风沙沉积粒度和地球化学元素两个环境代用指标的古气候意义,并通过区域对比和综合分析,初步建立区域风沙气候环境演变序列。结果表明:研究区灌丛沙堆主要发育于晚全新世,缺失早中全新世的风沙沉积。晚冰期以来,艾比湖地区的风沙气候环境演变经历了一系列冷湿（凉湿）-暖干（温干）的变化过程,其中暖干（温干）时期气候干旱,风力强劲,湖滨阶地主要发生风蚀过程,不利于灌丛沙堆的发育。晚全新世以来,艾比湖周边灌丛沙堆发育较普遍,风沙沉积至少记录了3次相对干旱期和3次相对湿润期。灌丛沙堆记录的风沙气候环境演化序列与北疆其他全新世沉积记录有较好的一致性,基本遵循晚次冰期以来气候变化的西风模式,同时也受到局地风沙地貌环境的影响。 相似文献
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灌丛沙丘形成演化及环境指示意义研究的主要进展 总被引：1，自引：0，他引：1
干旱半干旱区风沙活动较强烈, 风沙地貌十分发育, 环境演变过程对气候变化响应敏感。由于缺乏高分辨率载体, 在这些地区进行环境变化重建的手段及获得的结果相对贫乏。但是在这些区域发育的灌丛沙丘是风沙堆积体, 其形成演化记录了相对丰富的区域环境演变信息。本文综述了目前在灌丛沙丘形态学特征、发育过程、以及其在区域环境变化重建中的意义等方面的研究进展。我们认为, 灌丛沙丘形成演化研究在揭示干旱区环境演变过程方面有重大的意义, 但还没有形成系统的体系, 这一方面的研究仍有较大的空间。 相似文献
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为探究亚热带湿润地区河湖周边发育的灌丛沙堆形态与沉积特征,以南昌市厚田沙地为研究区,对其优势种蔓荆（Vitex trifolia）所形成的灌丛沙堆开展野外调查,通过对不同部位的沉积物进行采样与分析,研究沙堆形态、沉积特征及其与植被特性之间的关系。结果表明：蔓荆灌丛沙堆形态大多为盾形,水平尺度大,高度矮,坡度缓。沙堆沉积物以中沙为主,分选性较差,呈正偏和窄峰态分布,沙源来自附近平沙地和丘间地,为近源沉积。平均粒径从迎风坡底部至背风坡底部呈现为先变细后变粗的趋势,体现了灌丛沙堆的防风滞沙功能和对沙粒的重新分选作用。灌丛与沙堆的各形态参数（灌丛高度除外）均存在高度的正相关性（P＜0.01）,说明各形态参数在沙堆发育过程中得以协调发展。受植被类型和区域环境的影响,与干旱-半干旱地区直立生长且分支少的灌丛形成的椭球形或圆锥形沙堆形态不同,蔓荆匍匐生长且高度较矮的形态常形成低矮且范围较大的灌丛沙堆。亚热带湿润地区风力资源不丰富及厚田沙地沙源不足使沉积物主要来源于附近平沙地与丘间地,但不同坡位沉积规律与干旱-半干旱地区相同。 相似文献
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民勤荒漠绿洲过渡带白刺灌丛沙堆演化阶段及其空间格局 总被引：4，自引：0，他引：4
通过野外调查,分析了民勤荒漠绿洲过渡带不同地下水位埋深的3个白刺灌丛沙堆样方内灌丛沙堆水平投影面积与高度的关系、灌丛沙堆的空间分布及空间自相关关系,确定各个样方白刺灌丛沙堆的演化阶段,并分析了地下水位、沙源及植被生长对灌丛沙堆发展的影响。结果表明,白刺灌丛发育阶段灌丛沙堆的水平投影面积和高度之间为线性关系;稳定阶段白刺灌丛沙堆高度与水平投影面积为幂函数关系;退化阶段白刺灌丛沙堆高度和水平投影面积为二次函数关系。不同演化阶段白刺灌丛沙堆的空间自相关尺度为5 m,且3个样方之间自相关尺度没有显著差异。 相似文献
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新疆和田河流域柽柳沙堆的生物地貌发育过程 总被引：11，自引：0，他引：11
柽柳沙堆是我国干旱区分布最为广泛的灌丛沙堆类型之一.在实地考察新疆和田河流域柽柳生态地理特征、测量223个柽柳沙堆形态,并在两个野外观测点上实测4个沙堆的风沙流剖面,结合室内风洞实验段风速8 m/s条件下模拟沙堆风流场结构等综合分析方法,本文探讨了柽柳沙堆的生物地貌学特征及其发育过程.结果表明:研究区柽柳的生态类型属于以胡杨林与灌木林下土壤为基础的吐加依土生境类型,这个生境类型可以进一步划分为三个亚生境,这些亚生境反映了柽柳沙堆不同发育阶段的生态环境特征.由于柽柳灌丛的寿命长、木质化枝干的刚性较强、根株萌发力强耐风蚀沙埋,可对地面风沙流运行产生强烈扰动,其风速剖面有别于芦苇沙堆和骆驼刺沙堆,风流场结构有利于聚集风沙,因此风沙依托柽柳灌丛堆积发育而成的柽柳沙堆平均坡度较大、沙堆存活与发育的周期也较长. 相似文献
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白沙蒿(Artemisia sphaerocphala)灌丛沙堆是乌兰布和沙漠最为广泛分布的典型荒漠灌丛沙堆之一。本研究对白沙蒿灌丛的灌丛形态参数、沙堆形态参数进行了野外测定,探讨沙堆形态发育及固沙能力与白沙蒿灌丛形态的关系。结果表明:白沙蒿灌丛高度随着灌丛半径的增加而呈对数曲线增加,在灌丛较小时灌丛高度增长较快,随后渐趋于稳定,其水平方向发育速度大于垂直方向;白沙蒿灌丛沙堆半径及高度随灌丛半径和高度增加而增加,二者呈显著线性关系,沙堆水平方向发育受到灌丛冠幅的影响,沙堆垂直方向的发育水平取决于灌丛高度;随白沙蒿地上部分鲜重的增加,灌丛沙堆底面积、高度、沙堆体积和固沙效率均呈极显著线性增加(p0.01);白沙蒿灌丛越大其固积沙堆也越大,固沙率越高,不同大小灌丛白沙蒿间的固沙效率差异显著(p0.05);白沙蒿灌丛背风侧的积沙宽度(y)与积沙距离(x)显著相关(R2=0.9917),其线性回归方程为y=-19.654x+122.41,在距离灌丛背风面6~7倍高度的地方,积沙接近消失。 相似文献
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Nebkhas are often extensively distributed in arid and semi-arid areas, and play an important role in the stabilization of
ecological environment in these areas. This paper reviews the following aspects, including formation and succession, spatial
distribution, shape and surface airflow characteristics, balance between erosion and deposition, ecological and physiological
characteristics of vegetation, response to precipitation and groundwater, soil properties as well as the protection measures.
We found that nebkhas were studied without differentiation of succession periods, and shape characteristics, surface airflow,
soil properties as well as vegetation dynamics in different succession periods were not fully understood, which made it difficult
to explain the succession dynamics of nebkhas and its affecting factors. Previous studies of nebkhas were over-emphasized
for its role as an indicator of land degradation, while its ecological functions in degraded ecosystems were neglected, which
was unfavorable for the ecological restorations in arid and semi-arid areas. Future studies should pay more attention to the
variation of vegetation, soil as well as hydrological process in the succession of nebkhas and its interaction between different
influencing factors. In addition, positive role of nebkhas in degraded ecosystems in arid and semi-arid areas should be fully
discussed. According to the data got from the above, effective protection measures of nebkhas should be explored. 相似文献
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Nebkhas are often extensively distributed in arid and semi-arid areas, and play an important role in the stabilization of ecological environment in these areas. This paper reviews the following aspects, including formation and succession, spatial distribution, shape and surface airflow characteristics, balance between erosion and deposition, ecological and physiological characteristics of vegetation, response to precipitation and groundwater, soil properties as well as the protection measures. We found that nebkhas were studied without differentiation of succession periods, and shape characteristics, surface airflow, soil properties as well as vegetation dynamics in different succession periods were not fully understood, which made it difficult to explain the succession dynamics of nebkhas and its affecting factors. Previous studies of nebkhas were over-emphasized for its role as an indicator of land degradation, while its ecological functions in degraded ecosystems were neglected, which was unfavorable for the ecological restorations in arid and semi-arid areas. Future studies should pay more attention to the variation of vegetation, soil as well as hydrological process in the succession of nebkhas and its interaction between different influencing factors. In addition, positive role of nebkhas in degraded ecosystems in arid and semi-arid areas should be fully discussed. According to the data got from the above, effective protection measures of nebkhas should be explored. 相似文献
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《地理学报(英文版)》2010,(5)
Nebkhas are often extensively distributed in arid and semi-arid areas,and play an important role in the stabilization of ecological environment in these areas.This paper reviews the following aspects,including formation and succession,spatial distribution,shape and surface airflow characteristics,balance between erosion and deposition,ecological and physiological characteristics of vegetation,response to precipitation and groundwater,soil properties as well as the protection measures.We found that nebkhas were studied without differentiation of succession periods,and shape characteristics,surface airflow,soil properties as well as vegetation dynamics in different succession periods were not fully understood,which made it difficult to explain the succession dynamics of nebkhas and its affecting factors.Previous studies of nebkhas were over-emphasized for its role as an indicator of land degradation,while its ecological functions in degraded ecosystems were neglected,which was unfavorable for the ecological restorations in arid and semi-arid areas.Future studies should pay more attention to the variation of vegetation,soil as well as hydrological process in the succession of nebkhas and its interaction between different influencing factors.In addition,positive role of nebkhas in degraded ecosystems in arid and semi-arid areas should be fully discussed.According to the data got from the above,effective protection measures of nebkhas should be explored. 相似文献
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Anna Tengberg 《自然地理学》2013,34(4):259-275
Owing to the decline in rainfall and intensified land use in the Sahel during the past 25 years, wind erosion is causing increasing problems in this region. The aim of the present paper is to identify possible sources for the material found in nebkhas in northern Burkina Faso. Nebkhas are plant-obstacle dunes that frequently occur in semi-arid areas. Grain-size distributions of nebkha sediments and five other subenvironments were analyzed using univariate and multivariate methods. Quartz-grain surface textures were studied by Scanning Electron Microscopy (SEM). The SEM and grain-size analyses together indicate that the nebkhas have experienced considerable recent aeolian abrasion and sorting as compared with the five other sub-environments. It was concluded that the material in the nebkhas investigated is local in origin and that it mainly has been eroded by wind from adjacent disturbed soils or deflated from loose material made available for wind erosion by sheet-wash processes. This means that wind erosion is an important process in the removal of topsoil in this Sahelian environment and that measures to reduce wind erosion should be taken to protect sensitive soils. [Key words: Nebkhas, wind erosion, Sahel, Burkina Faso.] 相似文献
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《寒旱区科学》2021,13(3)
Nebkhas, discrete mounds of sand and vegetation, are a common landscape feature critical to the stability of desert ecosystems and supported by limited precipitation. Nebkha morphology and spatial pattern vary in landscapes, but it is unclear how they change along precipitation gradients in arid and semi-arid regions. In this study we determined morphology and soil nutrient patterns of nebkha from different regions of northwestern China. The objective of this study was to understand zonal differences among nebkhas and how morphological characteristics and soil nutrient patterns of nebkha change along a precipitation gradient in northwestern China. Our results shows that mean annual precipitation(MAP) had significant effects on morphological characteristics of nebkhas such as height, area, and volume which significantly decreased with an increase in MAP. MAP had significant positive effects on shrub cover and species richness of nebkha. Soil nutrients such as soil organic matter(SOM), total carbon(TC), total nitrogen(TN), and total phosphorus(TP) in the 0-10 cm layer increased with an increase of MAP, and soil nutrient content within nebkhas was higher than in inter-nebkha areas.We concluded that nebkhas are "fertile islands" with an important role in ecosystem dynamics in study regions. Further,MAP is a key factor which determined zonal differences, morphological, and soil nutrients patterns of nebkhas. However,disturbance, such as animal grazing, and planted sand-stabilizing vegetation accelerated the degeneration of nebkha landscapes. We recommend implementation of protective measures for nebkhas in arid and semi-arid areas of China. 相似文献
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灌丛沙堆是干旱、半干旱区绿洲边缘常见景观类型,在绿洲风沙防护及生物多样性保护方面有重要意义。本文对中国西北干旱区不同气候区常见的柽柳（Tamarix chinensis）、泡泡刺（Nitraria sphaerocarpa）和柠条锦鸡儿（Caragana korshinskii）灌丛沙堆形态和养分积累特征进行了对比研究。结果表明：柽柳灌丛沙堆高度、面积和体积显著高于泡泡刺和柠条锦鸡儿灌丛沙堆,泡泡刺灌丛沙堆高度、面积和体积最小。3种灌丛的存在都显著增加了沙堆土壤有机质含量,使灌丛沙堆成为“肥岛”,其中柽柳灌丛沙堆“肥岛”效应最明显。柽柳灌丛沙堆土壤有机质、全碳、全氮和凋落物含量显著高于泡泡刺和柠条锦鸡儿灌丛沙堆。主要原因是柽柳枝条茂密,拦截面积大且凋落物量大,因此沙物质拦截和养分积累能力强于其他两种灌丛。另外,不同气候区沙源和气象条件的差异也可能导致灌丛沙堆形态及养分累积特征不同。 相似文献
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Through high-resolution research of sedimental chronology and the sediment environmental indexes,such as graininess ,minerals,magnetic parameters,pigment content organic carbon and chronology in Ds-core and Ws-core in Nansihu Lake,the authors analyze the formation cause of the Nansihu Lake and its water environmental changes,Historical documents are also analyzed here in order to reach the conclusion .Researches indicate that the Nansihu Lake came into being about 2500 aBP and its evolution succession can be divided into four stages.In this evolution process ,several scattered lakes merge into one large lake in the east of China,This process is distinctively affected by the overflow of the Yellow River,the excavation of the Grand Canal and other human activities. 相似文献
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Through high-resolution research of sedimental chronology and the sediment environmental indexes, such as graininess, minerals, magnetic parameters, pigment content, organic carbon and chronology in Ds-core and Ws-core in Nansihu Lake, the authors analyze the formation cause of the Nansihu Lake and its water environmental changes. Historical documents are also analyzed here in order to reach the conclusion. Researches indicate that the Nansihu Lake came into being about 2500 aBP and its evolution succession can be divided into four stages. In this evolution process, several scattered lakes merge into one large lake in the east of China. This process is distinctively affected by the overflow of the Yellow River, the excavation of the Grand Canal and other human activities. 相似文献