Tamarix nabkha is one of the most widespread nabkhas, distributing in the arid region of China. Based on the observations outdoors and the simulation experiments in laboratories, analysis in this paper refers to the b...Tamarix nabkha is one of the most widespread nabkhas, distributing in the arid region of China. Based on the observations outdoors and the simulation experiments in laboratories, analysis in this paper refers to the biological geomorphologic features and growth process of Tamarix nabkhas in the middle and lower reaches of the Hotan River, Xinjiang. And the results indicate that the ecological type of Tamarix in the study area is a kind of Tugaic soil habitat based on the deep soil of the Populus Diversifolia forests and shrubs. This type of habitat can be divided into three kinds of sub-habitats which demonstrate the features of ecological environment of Tamarix nabkhas during the differential developed phases. Meanwhile, the Tamar, ix nabkha can exert intensified disturbance current on wind-sand flow on the ground,and its root and stems not only have strong potential of sprouting but are characteristic of wind erosion-tolerance, resistance to be buried by sand and respectively tough rigid of the lignified branches, for it has a rather longer life-time. Thus, the wind speed profile influenced by the Tamarix nabkha is different from the Phragmites nabkha and Alhagi nabkha. And the structure of the wind flow is beneficial to aeolian sand accumulating in/around Tamarix shrub, which can create unique Tamarix nabkhas with higher average gradient and longer periodicity of life. Tamarix nabkha evolution in the area experienced three stages： growth stage, mature and steady stage and withering stage. In each stage, morphological features and geomorphic process of Tamarix nabkha are different due to the discrep- ant interaction between the nabkha and aeolian sand flow.展开更多
Thirty coastal nabkhas were selected for morphometrical measurements. The studied nabkhas were mostly elongated, with an average total length of about 12.9 m, an average width of 3.4 m, and an average height of 1.2 m....Thirty coastal nabkhas were selected for morphometrical measurements. The studied nabkhas were mostly elongated, with an average total length of about 12.9 m, an average width of 3.4 m, and an average height of 1.2 m. Optical porosity of nabkha shrub crown was measured and no apparent relationship with the horizontal size of trapped wind laden sand was found. A simple wind tunnel experiment was carried out to investigate the horizontal wind-flow distribution across a pro-typed shrub. The results of the experiment revealed that the degree of wind sheltering might extend up to a downwind distance approximately equal to 4.5 times the height of the shrub, where an effective velocity recovery started.展开更多
在内蒙古高原,藏锦鸡儿(Caragana tibetica)群落分布在草原向荒漠的过渡带上,在植被区划中常作为由草原进入荒漠的指示物种。藏锦鸡儿是一种旱生垫状矮灌木,由于其垫状生物学特性,在地表覆沙的生境中常形成较均匀的、非常醒目的灌丛沙...在内蒙古高原,藏锦鸡儿(Caragana tibetica)群落分布在草原向荒漠的过渡带上,在植被区划中常作为由草原进入荒漠的指示物种。藏锦鸡儿是一种旱生垫状矮灌木,由于其垫状生物学特性,在地表覆沙的生境中常形成较均匀的、非常醒目的灌丛沙堆。不同大小的灌丛沙堆可对应其不同的发育阶段,选取不同大小的藏锦鸡儿灌丛沙堆,划分成小、中、大3组,小、中两组灌丛沙堆对应其发育阶段,大沙堆组对应于稳定阶段,通过测定沙堆间、沙堆内(顶部、中部)及沙堆下的土壤有机质(Soil organic matters,SOM)、全磷(Total phosphorus,TP)和土壤质量含水量(Mass water content of soil,Wm),分析了藏锦鸡儿群落土壤资源的特点。结果显示,随着沙堆的发育,沙堆内和堆下0～20cm处的土壤有机质、全磷和土壤质量含水量的平均含量呈递增趋势,大沙堆、中沙堆及堆下0～20cm处的土壤有机质、全磷和土壤质量含水量的平均含量均大于沙堆间,小沙堆的土壤有机质、堆下0～20cm的土壤全磷和质量含水量的平均含量大于沙堆间。不同大小的灌丛沙堆,在垂直方向上,土壤有机质、全磷含量基本均呈先增加后减少的趋势,土壤质量含水量呈递减趋势;在水平方向,随着灌丛沙堆的发育,土壤有机质、全磷和土壤质量含水量在同一部位的同一土层基本呈递增趋势;不同大小的沙堆表层0～20cm处的土壤有机质由顶部、中部、沙堆间依次呈先增加后减小的趋势;大沙堆和中沙堆的全磷由沙堆顶部、中部、沙堆间依次呈递减趋势,而小沙堆土壤全磷呈先增加后减少的趋势。随着灌丛沙堆的发育,藏锦鸡儿灌丛截获的植物残体量呈增加趋势。研究显示,藏锦鸡儿在发育过程中形成"沃岛效应",这种效应不仅表现在沙堆内,也表现在沙堆下,同时也引起土壤有机质、全磷和土壤水分的空间异质性分布。展开更多
In Kuwait, the scarcity and irregularity of rainfall, the availability of areas of sand supply and the prevalence of strong north westerly winds significantly influence the stability of the fragile ecosystem. Naturall...In Kuwait, the scarcity and irregularity of rainfall, the availability of areas of sand supply and the prevalence of strong north westerly winds significantly influence the stability of the fragile ecosystem. Naturally, grown native shrubs and trees can provide potential shelter to soil surface in desert areas. To study the environmental indicators provided by native plant and their ability to improve quality of life, the morphological properties of the vegetated nabkhas within different areas in Kuwait desert and within protected area were assessed. The vegetated dunes can trap maximum mobile sediments from 10.5 to 0.45 ton thus cost saving per plant estimated to be from 5.5 to 0.24 USD. The arrangements of the native plant from highest efficiency in absorbing carbon dioxides to the least were as follows: Nitraria retusa, Haloxylon salicornicum, Citrullus colocynthis, Tamarix aucheriana, Lycium shawii, Convolvolus oxyphyllus, Rhanterium epapposum, Panicum turgidum, Calligonum polygonoides, Astragalus spinosus, Cyperus conglomerates. The cost saving of CO_(2) per year estimated to be from 0.95 to 1,542.1 USD. The revegetation enhanced physical and chemical quality of soil and created microenvironments for the flora and fauna. The aim of this paper is to identify the environmental indicators related to native plants for the assessment of quality of life.展开更多
基金National Natural Science Foundation of China, No.40461002 The Key Project of the Ministry of Education, N0.205184
文摘Tamarix nabkha is one of the most widespread nabkhas, distributing in the arid region of China. Based on the observations outdoors and the simulation experiments in laboratories, analysis in this paper refers to the biological geomorphologic features and growth process of Tamarix nabkhas in the middle and lower reaches of the Hotan River, Xinjiang. And the results indicate that the ecological type of Tamarix in the study area is a kind of Tugaic soil habitat based on the deep soil of the Populus Diversifolia forests and shrubs. This type of habitat can be divided into three kinds of sub-habitats which demonstrate the features of ecological environment of Tamarix nabkhas during the differential developed phases. Meanwhile, the Tamar, ix nabkha can exert intensified disturbance current on wind-sand flow on the ground,and its root and stems not only have strong potential of sprouting but are characteristic of wind erosion-tolerance, resistance to be buried by sand and respectively tough rigid of the lignified branches, for it has a rather longer life-time. Thus, the wind speed profile influenced by the Tamarix nabkha is different from the Phragmites nabkha and Alhagi nabkha. And the structure of the wind flow is beneficial to aeolian sand accumulating in/around Tamarix shrub, which can create unique Tamarix nabkhas with higher average gradient and longer periodicity of life. Tamarix nabkha evolution in the area experienced three stages： growth stage, mature and steady stage and withering stage. In each stage, morphological features and geomorphic process of Tamarix nabkha are different due to the discrep- ant interaction between the nabkha and aeolian sand flow.
文摘Thirty coastal nabkhas were selected for morphometrical measurements. The studied nabkhas were mostly elongated, with an average total length of about 12.9 m, an average width of 3.4 m, and an average height of 1.2 m. Optical porosity of nabkha shrub crown was measured and no apparent relationship with the horizontal size of trapped wind laden sand was found. A simple wind tunnel experiment was carried out to investigate the horizontal wind-flow distribution across a pro-typed shrub. The results of the experiment revealed that the degree of wind sheltering might extend up to a downwind distance approximately equal to 4.5 times the height of the shrub, where an effective velocity recovery started.
文摘在内蒙古高原,藏锦鸡儿(Caragana tibetica)群落分布在草原向荒漠的过渡带上,在植被区划中常作为由草原进入荒漠的指示物种。藏锦鸡儿是一种旱生垫状矮灌木,由于其垫状生物学特性,在地表覆沙的生境中常形成较均匀的、非常醒目的灌丛沙堆。不同大小的灌丛沙堆可对应其不同的发育阶段,选取不同大小的藏锦鸡儿灌丛沙堆,划分成小、中、大3组,小、中两组灌丛沙堆对应其发育阶段,大沙堆组对应于稳定阶段,通过测定沙堆间、沙堆内(顶部、中部)及沙堆下的土壤有机质(Soil organic matters,SOM)、全磷(Total phosphorus,TP)和土壤质量含水量(Mass water content of soil,Wm),分析了藏锦鸡儿群落土壤资源的特点。结果显示,随着沙堆的发育,沙堆内和堆下0～20cm处的土壤有机质、全磷和土壤质量含水量的平均含量呈递增趋势,大沙堆、中沙堆及堆下0～20cm处的土壤有机质、全磷和土壤质量含水量的平均含量均大于沙堆间,小沙堆的土壤有机质、堆下0～20cm的土壤全磷和质量含水量的平均含量大于沙堆间。不同大小的灌丛沙堆,在垂直方向上,土壤有机质、全磷含量基本均呈先增加后减少的趋势,土壤质量含水量呈递减趋势;在水平方向,随着灌丛沙堆的发育,土壤有机质、全磷和土壤质量含水量在同一部位的同一土层基本呈递增趋势;不同大小的沙堆表层0～20cm处的土壤有机质由顶部、中部、沙堆间依次呈先增加后减小的趋势;大沙堆和中沙堆的全磷由沙堆顶部、中部、沙堆间依次呈递减趋势,而小沙堆土壤全磷呈先增加后减少的趋势。随着灌丛沙堆的发育,藏锦鸡儿灌丛截获的植物残体量呈增加趋势。研究显示,藏锦鸡儿在发育过程中形成"沃岛效应",这种效应不仅表现在沙堆内,也表现在沙堆下,同时也引起土壤有机质、全磷和土壤水分的空间异质性分布。
文摘In Kuwait, the scarcity and irregularity of rainfall, the availability of areas of sand supply and the prevalence of strong north westerly winds significantly influence the stability of the fragile ecosystem. Naturally, grown native shrubs and trees can provide potential shelter to soil surface in desert areas. To study the environmental indicators provided by native plant and their ability to improve quality of life, the morphological properties of the vegetated nabkhas within different areas in Kuwait desert and within protected area were assessed. The vegetated dunes can trap maximum mobile sediments from 10.5 to 0.45 ton thus cost saving per plant estimated to be from 5.5 to 0.24 USD. The arrangements of the native plant from highest efficiency in absorbing carbon dioxides to the least were as follows: Nitraria retusa, Haloxylon salicornicum, Citrullus colocynthis, Tamarix aucheriana, Lycium shawii, Convolvolus oxyphyllus, Rhanterium epapposum, Panicum turgidum, Calligonum polygonoides, Astragalus spinosus, Cyperus conglomerates. The cost saving of CO_(2) per year estimated to be from 0.95 to 1,542.1 USD. The revegetation enhanced physical and chemical quality of soil and created microenvironments for the flora and fauna. The aim of this paper is to identify the environmental indicators related to native plants for the assessment of quality of life.
