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1.
内蒙古温带草地植被的碳储量   总被引：18，自引：3，他引：18  
草地生态系统在全球碳循环中起着极为重要的作用。大部分草地碳储存在地下,但是实测数据十分匮乏,因此准确估算温带草地植被碳储量对评价草地生态系统碳循环具有重要意义。作为一个区域性资料积累工作,作者对内蒙古温带草地的碳储量进行了大范围的实测研究,以估算该地区草地植被的碳储量。主要结果如下:(1)内蒙古温带草地总面积为58.46×106hm2,总植被碳储量为226.0±13.27Tg C(1 Tg=1012g),平均碳密度为3.44Mg C.hm-2;(2)地下根系储存的碳是地上碳储量的6倍左右,地上、地下生物量碳储量分别为33.22±1.75和193.88±12.6 Tg C,平均碳密度分别是0.51和2.96 MgC.hm-2;(3)不同草地类型的碳储量差异较大,典型草原最大(113.25 Tg C),占草地总碳储量的50%,其次是草甸和草甸草原,荒漠草原碳储量最低(15.37 Tg C)。  相似文献   

2.
Soil carbon pools could become a CO_2 source or sink, depending on the directions of land use/cover changes. A slight change of soil carbon will inevitably affect the atmospheric CO_2 concentration and consequently the climate. Based on the data from 127 soil sample sites, 48 vegetation survey plots, and Landsat TM images, we analyzed the land use/cover changes, estimated soil organic carbon(SOC) storage and vegetation carbon storage of grassland, and discussed the impact of grassland changes on carbon storage during 2000 to 2013 in the Ili River Valley of Northwest China. The results indicate that the areal extents of forestland, shrubland, moderate-coverage grassland(MCG), and the waterbody(including glaciers) decreased while the areal extents of high-coverage grassland(HCG),low-coverage grassland(LCG), residential and industrial land, and cultivated land increased. The grassland SOC density in 0–100 cm depth varied with the coverage in a descending order of HCGMCGLCG.The regional grassland SOC storage in the depth of 0–100 cm in 2013 increased by 0.25×1011 kg compared with that in 2000. The regional vegetation carbon storage(S_(rvc)) of grassland was 5.27×10~9 kg in2013 and decreased by 15.7% compared to that in 2000. The vegetation carbon reserves of the under-ground parts of vegetation(S_(ruvb)) in 2013 was 0.68×10~9 kg and increased by approximately 19.01%compared to that in 2000. This research can improve our understanding about the impact of land use/cover changes on the carbon storage in arid areas of Northwest China.  相似文献   

3.
Land use change significantly influences soil properties.There is little information available on the long-term effects of post-reclamation from grassland to cropland on soil properties.We compared soil carbon(C) and nitrogen(N) storage and related soil properties in a 50-year cultivation chronosequence of grassland in the agro-pastoral ecotone of Inner Mongolia.Field surveys on land use changes during the period of 1955-2002 were conducted to build a chronosequence of cropland of different ages since the conversion from grassland.The results showed that soil C and N storage,soil texture,and soil nutrient contents varied with land use types and cropland ages(P<0.01).In the 0-30 cm soil layer,the soil organic carbon(SOC) density was significantly lower in the croplands(3.28 kg C/m2 for C50 soil) than in the grasslands(6.32 kg C/m2).After 5,10,15,20,35,and 50 years of crop planting(years since the onset of cultivation),the SOC losses were 17%,12%,19%,47%,46%,and 48%,respectively,compared with the grasslands.The soil total nitrogen(TN) density of the grasslands was 65 g N/m2,and TN density of the cropland soil was 35 g N/m2 after 50 years of crop planting.Both the SOC and TN densities could be quantitatively determined by a negative exponential function of cropland age(P<0.0001,R2=0.8528;P<0.0001,R2=0.9637).The dissolved organic carbon(DOC) content,soil available potassium(AK) content,clay content,and pH value were decreased;and the soil bulk density and sand content were increased since the conversion of grassland into cropland during the 50-year period.Our results show soil nutrients were higher in grassland than in cropland.The conversion of grasslands to croplands induced a loss of soil C storage and changes of related soil properties.The reclamation time of cultivated soil(cropland age) had significant effects on soil properties in the study area.  相似文献   

4.
With increasingly intensifying degradation of natural grasslands and rapidly increasing demand of high quality forages, natural grasslands in China have been converted into planted grasslands at an unprecedented rate and the magnitude of the conversion in Inner Mongolia is among the national highest where the areal extent of planted grasslands ranks the second in China. Such land-use changes(i.e., converting natural grasslands into planted grasslands) can significantly affect carbon stocks and carbon emissions in grassland ecosystems. In this study, we analyzed the effects of converting natural grasslands into planted grasslands(including Medicago sativa, Elymus cylindricus, and M. sativa+E. cylindricus) on ecosystem respiration(F_(eco)) in Inner Mongolia of China. Diurnal F_(eco) and its components(i.e., total soil respiration(F_(ts)), soil heterotrophic respiration(F_(sh)) and vegetation autotrophic respiration(F_(va))) were measured in 2012(27 July to 5 August) and 2013(18 July to 25 July) in the natural and planted grasslands. Meteorological data, aboveground vegetation data and soil data were simultaneously collected to analyze the relationships between respiration fluxes and environmental factors in those grasslands. In 2012, the daily mean F_(eco) in the M. sativa grassland was higher than that in the natural grassland, and the daily mean F_(va) was higher in all planted grasslands(i.e., M. sativa, E. cylindricus, and M. sativa+E. cylindricus) than in the natural grassland. In contrast, the daily mean F_(ts) and F_(sh) were lower in all planted grasslands than in the natural grassland. In 2013, the daily mean F_(eco), F_(ts) and F_(va) in all planted grasslands were higher than those in the natural grassland, and the daily mean F_(sh) in the M. sativa+E. cylindricus grassland was higher than that in the natural grassland. The two-year experimental results suggested that the conversion of natural grasslands into planted grasslands can generally increase the F_(eco) and the increase in F_(eco) is more pronounced when the plantation becomes more mature. The results also indicated that F_(sh) contributed more to F_(eco) in the natural grassland whereas F_(va) contributed more to F_(eco) in the planted grasslands. The regression analyses show that climate factors(air temperature and relative humidity) and soil properties(soil organic matter, soil temperature, and soil moisture) strongly affected respiration fluxes in all grasslands. However, our observation period was admittedly too short. To fully understand the effects of such land-use changes(i.e., converting natural grasslands into planted grasslands) on respiration fluxes, longer-term observations are badly needed.  相似文献   

5.
Plant root exudates contain various organic and inorganic components that include glucose, citric and oxalic acid. These components affect rhizosphere microbial and microfaunal activities, but the mechanisms are not fully known. Studies concerned from degraded grassland ecosystems with low soil carbon（C） contents are rare, in spite of the global distribution of grasslands in need of restoration. All these have a high potential for carbon sequestration, with a reduced carbon content due to overutilization. An exudate component that rapidly decomposes will increase soil respiration and CO2 emission, while a component that reduces decomposition of native soil carbon can reduce CO2 emission and actually help sequestering carbon in soil. Therefore, to investigate root exudate effects on rhizosphere activity, citric acid, glucose and oxalic acid（0.6 g C/kg dry soil） were added to soils from three biotopes（grassland, fixed dune and mobile dune） located in Naiman, Horqin Sandy Land, Inner Mongolia, China） and subjected to a 24-day incubation experiment together with a control. The soils were also analyzed for general soil properties. The results show that total respiration without exudate addition was highest in grassland soil, intermediate in fixed dune and lowest in mobile dune soil. However, the proportion of native soil carbon mineralized was highest in mobile dune soil, reflecting the low C/N ratio found there. The exudate effects on CO2-C emissions and other variables differed somewhat between biotopes, but total respiration（including that from the added substrates） was significantly increased in all combinations compared with the control, except for oxalic acid addition to mobile dune soil, which reduced CO2-C emissions from native soil carbon. A small but statistically significant increase in pH by the exudate additions in grassland and fixed dune soil was observed, but there was a major decrease from acid additions to mobile dune soil. In contrast, electrical conductivity decreased in grassland  相似文献   

6.
The main purpose of this study was to explore the dynamic changes of greenhouse gas(GHG)from grasslands under different degradation levels during the growing seasons of Inner Mongolia, China.Grassland degradation is associated with the dynamics of GHG fluxes, e.g., CO_2, CH_4 and N_2O fluxes. As one of the global ecological environmental problems, grassland degradation has changed the vegetation productivity as well as the accumulation and decomposition rates of soil organic matter and thus will influence the carbon and nitrogen cycles of ecosystems, which will affect the GHG fluxes between grassland ecosystems and the atmosphere. Therefore, it is necessary to explore how the exchanges of CO_2,CH_4 and N_2O fluxes between soil and atmosphere are influenced by the grassland degradation. We measured the fluxes of CO_2, CH_4 and N_2O in lightly degraded, moderately degraded and severely degraded grasslands in Inner Mongolia of China during the growing seasons from July to September in 2013 and 2014. The typical semi-arid grassland of Inner Mongolia plays a role as the source of atmospheric CO_2 and N_2O and the sink for CH_4. Compared with CO_2 fluxes, N_2O and CH_4 fluxes were relatively low. The exchange of CO_2, N_2O and CH_4 fluxes between the grassland soil and the atmosphere may exclusively depend on the net exchange rate of CO_2 in semi-arid grasslands. The greenhouse gases showed a clear seasonal pattern, with the CO_2 fluxes of –33.63–386.36 mg/(m·h), CH_4 uptake fluxes of 0.113–0.023 mg/(m·h) and N_2O fluxes of –1.68–19.90 μg/(m·h). Grassland degradation significantly influenced CH_4 uptake but had no significant influence on CO_2 and N_2O emissions. Soil moisture and temperature were positively correlated with CO_2 emissions but had no significant effect on N_2O fluxes.Soil moisture may be the primary driving factor for CH_4 uptake. The research results can be in help to better understand the impact of grassland degradation on the ecological environment.  相似文献   

7.
The soil properties in arid ecosystems are important determinants of vegetation distribution patterns.Soil organic carbon(SOC)content,which is closely related to soil types and the holding capacities of soil water and nutrients,exhibits complex variability in arid desert grasslands;thus,it is essentially an impact factor for the distribution pattern of desert grasslands.In the present study,an investigation was conducted to estimate the spatial pattern of SOC content in desert grasslands and the association with environmental factors in the diluvial-alluvial plains of northern Qilian Mountains.The results showed that the mean values of SOC ranged from 2.76 to 5.80 g/kg in the soil profiles,and decreased with soil depths.The coefficients of variation(CV)of the SOC were high(ranging from 48.83%to 94.67%),which indicated a strong spatial variability.SOC in the desert grasslands of the study region presented a regular spatial distribution,which increased gradually from the northwest to the southeast.The SOC distribution had a pattern linked to elevation,which may be related to the gradient of climate conditions.Soil type and plant community significantly affected the SOC.The SOC had a significant positive relationship with soil moisture(P<0.05);whereas,it had a more significant negative relationship with the soil bulk density(BD)(P<0.01).However,a number of the variations in the SOC could be explained not by the environmental factors involved in this analysis,but rather other factors(such as grazing activity and landscape).The results provide important references for soil carbon storage estimation in this study region.In addition,the SOC association with environmental variables also provides a basis for a sustainable use of the limited grassland resources in the diluvial-alluvial plains of northern Qilian Mountains.  相似文献   

8.
China's Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon(C) losses from the plant-soil system.Natural restoration through grazing exclusion is a widely suggested option to sequester C and to restore degraded land.In a desertified grassland,we investigated the C accumulation in the total and light fractions of the soil organic matter from 2005 to 2013 during natural restoration.To a depth of 20 cm,the light fraction organic carbon(LFOC) storage increased by 221 g C/m2(84%) and the total soil organic carbon(SOC) storage increased by 435 g C/m2(55%).The light fraction dry matter content represented a small proportion of the total soil mass(ranging from 0.74% in 2005 to 1.39% in 2013),but the proportion of total SOC storage accounted for by LFOC was remarkable(ranging from 33% to 40%).The C sequestration averaged 28 g C/(m2·a) for LFOC and 54 g C/(m2·a) for total SOC.The total SOC was strongly and significantly positively linearly related to the light fraction dry matter content and the proportions of fine sand and silt+clay.The light fraction organic matter played a major role in total SOC sequestration.Our results suggest that grazing exclusion can restore desertified grassland and has a high potential for sequestering SOC in the semiarid Horqin Sandy Land.  相似文献   

9.
内蒙古碳汇资源估算与碳汇产业发展潜力分析   总被引：3，自引：0，他引：3  
《京都议定书》的签署,使碳汇成为一种稀缺资源并引起了高度的重视。有前瞻性的国家和地区应该认识到发展碳汇产业的前景。文中定义了碳汇产业的概念,分别采用森林蓄积量扩展法、碳密度方法、李克让和T.O.West的提出的方法对内蒙古的森林、草地、农田碳汇资源进行了估算,2003年为172049.1万t,2009年为180948.2万t。对内蒙古碳汇产业发展进行了潜力分析,并提出了具体的发展对策和建议。  相似文献   

10.
内蒙古是我国风力侵蚀较为严重的地区之一,同时也是我国土地利用方式剧烈变化的地区之一。依据两期土地利用数据以及相应年代的土壤风力侵蚀数据,研究了20世纪90年代内蒙古自治区土地利用和风力侵蚀的静、动态格局。根据土地利用和风力侵蚀的空间分布及动态变化特点,设计了内蒙古土地利用—风力侵蚀动态区划,基于该区划详细讨论了内蒙古不同地区占主导地位的土地利用动态与风力侵蚀动态,由此揭示了两者之间存在的驱动——被驱动关系。研究发现,在过去10年里,内蒙古土地利用和风力侵蚀的基本格局没有太大变化,但风力侵蚀在总体上是增强了,而土地利用的变化主要反映为草地的退化和耕地的扩张。土地利用动态与风力侵蚀动态有着良好的时空对应关系草地的退化与耕地的扩张导致了显著的风力侵蚀增强,而草地的改善以及耕地的收缩对风力侵蚀的影响不是很大,这同时也表明了土地利用动态对风力侵蚀动态正、反向驱动力的不平衡性。  相似文献   

11.
内蒙古草原土壤斥水性的季节变化   总被引：2，自引：0，他引：2  
土壤斥水性是指水分不能或很难湿润土壤颗粒表面的物理现象,具有斥水性的土壤称为斥水土壤。本文以内蒙古锡林浩特市白音锡勒牧场中国科学院内蒙古草原生态系统定位站的羊草样地为例,运用滴水穿透时间法分析了1979年禁牧1、999年禁牧、冬季放牧和连续放牧等条件下内蒙草原土壤斥水性的季节变化。结果表明:草原土壤总体上表现为轻度斥水性或无斥水性,且斥水性具有显著的季节变化特点,一般在雨季或多雨年土壤具有较强的斥水性;不同的利用方式对草原土壤斥水性的季节变化规律具有一定的影响,存在时间上的滞后性,持续放牧处理在雨季较多的样点最先表现斥水性,其次为冬季放牧处理,然后为1999年禁牧处理,最后为1979年禁牧处理。  相似文献   

12.
Carbon(C) storage has received significant attention for its relevance to agricultural security and climate change. Afforestation can increase C storage in terrestrial ecosystems, and has been recognized as an important measure to offset CO_2 emissions. In order to analyze the C benefits of planting wolfberry(Lycium barbarum L.) on the secondary saline lands in arid areas, we conducted a case study on the dynamics of biomass carbon(BC) storage and soil organic carbon(SOC) storage in different-aged wolfberry plantations(4-, 7-and 11-year-old) established on a secondary saline land as well as on the influence of wolfberry plantations on C storage in the plant-soil system in an arid irrigated area(Jingtai County) of Gansu Province, China. The C sequestration and its potential in the wolfberry plantations of Gansu Province were also evaluated. An intact secondary saline land was selected as control. Results show that wolfberry planting could decrease soil salinity, and increase BC, SOC and litter C storage of the secondary saline land significantly, especially in the first 4 years after planting. The aboveground and belowground BC storage values in the intact secondary saline land(control) accounted for only 1.0% and 1.2% of those in the wolfberry plantations, respectively. Compared to the intact secondary saline land, the SOC storage values in the 4-, 7-and 11-year-old wolfberry plantations increased by 36.4%, 37.3% and 43.3%, respectively, and the SOC storage in the wolfberry plantations occupied more than 92% of the ecosystem C storage. The average BC and SOC sequestration rates of the wolfberry plantations for the age group of 0–11 years were 0.73 and 3.30 Mg C/(hm~2·a), respectively. There were no significant difference in BC and SOC storage between the 7-year-old and 11-year-old wolfberry plantations, which may be due in part to the large amounts of C offtakes in new branches and fruits. In Gansu Province, the C storage in the wolfberry plantations has reached up to 3.574 Tg in 2013, and the C sequestration potential of the existing wolfberry plantations was 0.134 Tg C/a. These results indicate that wolfberry planting is an ideal agricultural model to restore the degraded saline lands and increase the C sequestration capacity of agricultural lands in arid areas.  相似文献   

13.
内蒙古自治区森林碳储量及其动态变化   总被引：4，自引：2，他引：2  
利用内蒙古森林资源清查资料,依据不同森林类型生物量和蓄积量之间的回归方程,估算了内蒙古自治区不同时段的森林生物量和碳储量,并分析其动态变化特征。结果表明：在1977-2003年间内蒙古森林面积由1.10×10^7hm^2增加到1.61×10^7hm^2,每年森林面积平均增长率为1.85%;森林碳储量由378.86TgC...  相似文献   

14.
草地生态系统在全球碳循环中起着极为重要的作用。但是实测数据十分匮乏,文中利用2008年全国草原地面监测数据,以及卫星遥感数据,对2008年中国草地的碳储量进行了估算。主要结论如下:中国草地总面积约为341.7×104km2,2008年中国草地总有机碳为35.96Pg,其中地上生物量有机碳为0.1613Pg,地下生物量碳为0.7395Pg,地下根系储存的碳是地上碳储量的5倍左右,中国草地土壤有机碳为35.06Pg。  相似文献   

15.
BI Xu  LI Bo  NAN Bo  FAN Yao  FU Qi  ZHANG Xinshi 《干旱区科学》2018,10(4):612-627
Soil organic carbon(SOC) and soil total nitrogen(STN) in arid regions are important components of global C and the N cycles, and their response to climate change will have important implications for both ecosystem processes and global climate feedbacks. Grassland ecosystems of Funyun County in the southern foot of the Altay Mountains are characterized by complex topography, suggesting large variability in the spatial distribution of SOC and STN. However, there has been little investigation of SOC and STN on grasslands in arid regions with a mountain-basin structure. Therefore, we investigated the characteristics of SOC and STN in different grassland types in a mountain-basin system at the southern foot of the Altai Mountains, north of the Junggar Basin in China, and explored their potential influencing factors and relationships with meteorological factors and soil properties. We found that the concentrations and storages of SOC and STN varied significantly with grassland type, and showed a decreasing trend along a decreasing elevation gradient in alpine meadow, mountain meadow, temperate typical steppe, temperate steppe desert, and temperate steppe desert. In addition, the SOC and STN concentrations decreased with depth, except in the temperate desert steppe. According to Pearson's correlation values and redundancy analysis, the mean annual precipitation, soil moisture content and soil available N concentration were significantly positively correlated with the SOC and STN concentrations. In contrast, the mean annual temperature, p H, and soil bulk density were significantly and negatively correlated with the SOC and STN concentrations. The mean annual precipitation and mean annual temperature were the primary factors related to the SOC and STN concentrations. The distributions of the SOC and STN concentrations were highly regulated by the elevation-induced differences in meteorological factors. Mean annual precipitation and mean annual temperature together explained 97.85% and 98.38% of the overall variations in the SOC and STN concentrations, respectively, at soil depth of 0–40 cm, with precipitation making the greatest contribution. Our results provide a basis for estimating and predicting SOC and STN concentrations in grasslands in arid regions with a mountain-basin structure.  相似文献   

16.
Horqin Sandy Land is a fragile,seriously desertified region located in Inner Mongolia of China.Overgrazing is one of the primary drivers of desertification in this region.We investigated whether the establishment of grazing exclosures in areas with active sand dunes enhances soil carbon(C) sequestration and benefits soil recovery.The results showed that soil organic C storage was 1.4,1.9,and 3.5 times,and light fraction C storage was 2.3,3.2,and 4.4 times in the 100-cm topsoil after 7,12,and 25 years of grazing exclusion,respectively,compared to the case in active sand dunes.The light fraction of soil played an important role in soil C sequestration,although it might not change rapidly to provide an early indication of how soil C is increasing in response to grazing exclusion.The results indicated that soils could potentially sequester up to 13.8 Mt C in 25 years if active sand dunes in the study area were to be protected by exclosures.This corresponds to 12.8% of the estimated carbon loss(107.53 Mt) that has been associated with desertification over the past century in the Horqin Sandy Land.Our results suggested that exclosures have the capacity to increase soil C sequestration;however,decades will be required for soil C to recover to historical grassland levels observed prior to desertification.  相似文献   

17.
为了准确评估土壤水分盈亏状况,在墒情评估中引入土壤有效水下限概念,提出单站单标准的墒情评估体系。结果表明:内蒙古自动土壤水分观测站凋萎湿度和田间持水量整体偏高,区域主要集中在东部区、河套地区和阴山山脉,相对偏低区域主要在锡林郭勒盟和西部区,偏低区土地类型以草原和荒漠区为主。整体来看,相对凋萎湿度东部高于中西部,东部偏南最高;相对凋萎湿度(6.57%～55.15%)波动较大,在田间持水量至相对凋萎湿度之间根据等间距划分得到二类、三类墒情上限范围为68.86%～85.05%和37.71%～70.07%,地区间墒情标准等级差异较大,二、三类墒情从地理位置来看,东部区中部区西部区锡林郭勒盟草原区,从土地利用分区来看,农林区域要明显大于草原区,其中内蒙古中西部的乌兰察布—土默川农业区、阴山丘陵农业区、河套灌区要明显高于周边草原区。  相似文献   

18.
通过分析内蒙古草原生态补偿标准存在的问题,确定内蒙古草原生态补偿标准应该包含三方面的内容：直接成本、机会成本和草原生态服务功能价值。根据内蒙古经济社会发展现状及草原生态退化程度确定内蒙古草原生态补偿应处于第三个阶段,即＂补偿标准=直接成本＋全部机会成本＂,并以内蒙古禁牧为例,以全国城镇居民人均可支配收入和农村居民人均纯...  相似文献   

19.
HAI Xuying 《干旱区科学》2022,14(10):1109-1123
Manipulated precipitation patterns can profoundly influence the metabolism of soil microorganisms. However, the responses of soil organic carbon (SOC) and nutrient turnover to microbial metabolic limitation under changing precipitation conditions remain unclear in semi-arid ecosystems. This study measured the potential activities of enzymes associated with carbon (C: β-1,4-glucosidase (BG) and β-D-cellobiosidase (CBH)), nitrogen (N: β-1,4-N-acetylglucosaminidase (NAG) and L-leucine aminopeptidase (LAP)) and phosphorus (P: alkaline phosphatase (AP)) acquisition, to quantify soil microbial metabolic limitations using enzymatic stoichiometry, and then identify the implications for soil microbial metabolic limitations and carbon use efficiency (CUE) under decreased precipitation by 50% (DP) and increased precipitation by 50% (IP) in a temperate grassland. The results showed that soil C and P were the major elements limiting soil microbial metabolism in temperate grasslands. There was a strong positive dependence between microbial C and P limitations under manipulated precipitation. Microbial metabolism limitation was promoted by DP treatment but reversed by IP treatment. Moreover, CUE was inhibited by DP treatment but promoted by IP treatment. Soil microbial metabolism limitation was mainly regulated by soil moisture and soil C, N, and P stoichiometry, followed by available nutrients (i.e., NO- 3, NH+ 4, and dissolved organic C) and microbial biomass (i.e., MBC and MBN). Overall, these findings highlight the potential role of changing precipitation in regulating ecosystem C turnover by limiting microbial metabolism and CUE in temperate grassland ecosystems.  相似文献   

20.
基于GIS的内蒙古人居环境适宜性评价   总被引：1，自引：0，他引：1  
以1km×1km栅格为基本单元,建立地形、气候、水文和地被等人居环境单要素评价模型和人居环境综合评价模型,系统评估了内蒙古人居自然环境的适宜性与限制性,定量揭示了内蒙古人居环境的地域类型与空间格局。研究表明:内蒙古地形条件较好、气候偏寒、水文和植被条件较差,自然条件是影响内蒙古人口分布的重要因素;内蒙古人居环境以限制性为主要特征,自治区人居环境由41.15%的不适宜区、37.07%的临界适宜区以及21.78%的适宜区组成,不适宜人类长年生活和居住的地区面积最大;内蒙古人居环境的限制性,决定了自治区人口"大集中、小分散"的基本分布格局,全区88.03%的人口集中在面积有限的25.75×104km2人居环境适宜地区,人居环境临界适宜地区占地43.84×104km2,人口不足全区的10%;人居环境不适宜地区占地48.66×104km2,人口仅占全区的2.24%。  相似文献   

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