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1.
Spatial patterns of plant species and patchy community are important properties in grasslands. However, research regarding spatial patterns of formed patches with various species has not fully advanced until now. Our purpose is to clarify differences in spatial pattern formed by species and community constructed under shady and terrace habitats. The three common Kobresia-Carex patches(Size 1, 0.6–0.9 m2; Size 2, 3.0–3.8 m2 and Size 3, 6.5–8.8 m2)were selected in ...  相似文献   

2.
Leaf area is an important parameter for modeling plant growth and physiological processes.It is very expensive and difficult for measuring leaf area by means of Leaf Area Meter,therefore,it’s quite necessary to obtain one simple model for estimation of leaf area of mangrove tree.The models for estimation of leaf area of 3 species of mangrove trees were developed based on leaf length and width.Totally,leaf area(LA),leaf length(L)and width(W)were measured from 450 fresh leaves of major three species of mangrove trees in Zhangjiang Estuary Mangrove National Natural Reserve,Fujian province.The actual leaf area of the plant was measured with the help of ArcGIS software and regression model was fitted.The majority of the data(80%)were used for model calibration,and the remaining data(20%)were used for model validation.All the leaf areas of 3 species of mangrove trees had been significant correlation between L,W,L·W,L2,W2and(L+W)2,so the factors could be constructed into a regression model with leaf area.Six models for estimation of leaf area selected were significantly(p0.001)regressed with L,W and the functions of these dimensions.All models were linear relationships.Based on goodness of fit,prediction ability and residual performance,it was found that model 3 could best describe the relationship between leaf area and leaf length and width.By means of regression analysis,the following models were developed:LA=0.28+0.66L·W(R2=0.980)for Kandelia candel,LA=0.09+0.73L·W(R2=0.983)for Avicennia marina,LA=0.52+0.72L·W(R2=0.990)for Aegiceras corniculatum,respectively.The study provided a simple,reliable and non-destructive method for estimating single leaf area.It had a good potential in the functional structural model of mangrove tree.  相似文献   

3.
Soil humic carbon is an important component of soil organic carbon(SOC) in terrestrial ecosystems. However, no study to date has investigated its geographical patterns and the main factors that influence it at a large scale, despite the fact that it is critical for exploring the influence of climate change on soil C storage and turnover. We measured levels of SOC, humic acid carbon(HAC), fulvic acid carbon(FAC), humin carbon(HUC), and extractable humus carbon(HEC) in the 0–10 cm soil layer in nine typical forests along the 3800-km North-South Transect of Eastern China(NSTEC) to elucidate the latitudinal patterns of soil humic carbon fractions and their main influencing factors. SOC, HAC, FAC, HUC, and HEC increased with increasing latitude(all P0.001), and exhibited a general trend of tropical subtropical temperate. The ratios of humic C fractions to SOC were 9.48%–12.27%(HAC), 20.68%–29.31%(FAC), and 59.37%–61.38%(HUC). Climate, soil texture, and soil microbes jointly explained more than 90% of the latitudinal variation in SOC, HAC, FAC, HEC, and HUC, and interactive effects were important. These findings elucidate latitudinal patterns of soil humic C fractions in forests at a large scale, and may improve models of soil C turnover and storage.  相似文献   

4.
Leaf carbon content(LCC) is widely used as an important parameter in estimating ecosystem carbon(C) storage,as well as for investigating the adaptation strategies of vegetation to their environment at a large scale.In this study,we used a dataset collected from forests(5119 plots) and shrublands(2564 plots) in China,2011–2015.The plots were sampled following a consistent protocol,and we used the data to explore the spatial patterns of LCC at three scales:plot scale,eco-region scale(n = 24),and eco-region scale(n = 8).The average LCC of forests and shrublands combined was 45.3%,with the LCC of forests(45.5%) being slightly higher than that of shrublands(44.9%).Forest LCC ranged from 40.2% to 51.2% throughout the 24 eco-regions,while that of shrublands ranged from 35% to 50.1%.Forest LCC decreased with increasing latitude and longitude,whereas shrubland LCC decreased with increasing latitude,but increased with increasing longitude.The LCC increased,to some extent,with increasing temperature and precipitation.These results demonstrate the spatial patterns of LCC in the forests and shrublands at different scales based on field-measured data,providing a reference(or standard) for estimating carbon storage in vegetation at a regional scale.  相似文献   

5.
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   

6.
Plant moisture content(PMC) is used as an indicator of forest flammability, which is assumed to be affected by climate drought. However, the fire-induced drought stress on PMC and its spatial and temporal variations are unclear. Based on a parallel monitoring experiment from 2014 to 2015, this study compared the PMCs and soil moisture contents(SMC) at five post-fire sites in central Yunnan Plateau, Southwest China. The number of years since last fire(YSF), season, topographic position, plant species and tissue type(leaf and branch) were selected as causal factors of the variations in PMC and SMC. A whole year parallel monitoring and sampling in the post-fire communities of 1, 2, 5, 11 and 30 YSF indicated that drought stress in surface soils was the strongest in spring within the first 5 years after burning, and the SMC was regulated by topography, with 64.6% variation in soil moisture accounted for by YSF(25.7%), slope position(22.1%) and season(10.8%). The temporal variations of PMC and SMC differed at both interannual and seasonal scales, but the patterns were consistent across topographic positions. PMC differed significantly between leaves and branches, and among three growth-forms. The mean PMC was lower in broad-leaved evergreen species and higher in conifer species. Season and soil temperature were the primary determinants of PMC, accounting for 19.1% and 8.3% of variation in PMC, respectively. This indicated phenology-related growth rather than drought stress in soil as the primary driver of seasonal changes in PMC. The significant variations of PMC among growth forms and species revealed that seasonal soil temperature change and dominant species in forest communities are useful indicators of fire risk assessment in this region.  相似文献   

7.
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8.
The method for simulating the temporal and spatial distribution patterns of leaf area index (LAI) and biomass at landscape scale using remote sensing images and surface data was discussed in this paper,The procedure was:(1) annual maximum normalized difference vegetation index (NDVI) over the landscape was calculated from TM images;(2) the relationship model between NDVI and LAI was built and annual maximum LAI over the landscape was simulated;(3) the relationship models between LAI and biomass were built and annual branch ,stem ,root and maximum leaf biomass over the landscape were simulated;(4) spatial distribution patterns of leaf biomass and LAI in different periods all the year round were obtained.The simulation was based on spatial analysis module GRID in ArcoInfo software ,The method is laso a kind of scaling method from patch scale to landscape scale ,A case study of Changbai Mountain Nature Reserve was dissertated ,Aalysis and primary validation were carried out to the simulated LAI and biomass for the major vegetation types in the Changbai Mountain in 1995.  相似文献   

9.
The content characteristics of 16 elements (Al, Ca, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sr, and Zn) in 23 plant species collected from the Qinghai-Tibetan Plateau permafrost region were investigated using ICP-OES. Results show that the average contents of Ca, K, Mg, Fe and P were higher than 1,000 mg/kg, those of Al, Na, Zn and Cr ranged between 10–1,000 mg/kg and those of Cu, Li, Pb and Mo were less than 10 mg/kg. The levels of Al, Ca, K, Mg and Na were within the scope of the reported terrestrial plant element content, those of Sr, Fe and Cr were higher than the average of the terrestrial plants and the maximum content of Mn was higher than the upper limit of the reported Mn content. The main character of the element content was of the Ca>K type, however, in terms of Cyperaceae species the element content character was K>Ca type. The contents of Ca, Li, Mg and Sr in Gramineae and Cyperaceae species were higher than those in other species and the contents of Ca, K, Mg, Fe, P, Al and Na in all collected plants were higher than those of other elements. Zn had weak variability with the lowest coefficient (i.e., 7.81%), while other elements had strong variability. The ratio of maximum content to minimum content indicated Ca and K had less change than other elements in the Qinghai-Tibetan Plateau permafrost region. Element content of alpine vegetation in the Qinghai-Tibetan Plateau permafrost region mainly shows a positive correlation, among which the correlation coefficient between Al and Pb, Al and Fe, Mo and Cr, Pb and Fe, Sr and Li were higher than 0.9, and negative correlation had no statistical significance. The correlation between Al and Fe, Mg, Mn in the Qinghai-Tibetan Plateau permafrost region were consistent with that reported in Kunlun Mountains.  相似文献   

10.
Investigations on plant community and micronutrient status of Schirmacher Oasis,East Antarctica have been presented in this paper.The dominant plant com- munities include moss and lichen.The frequency of species occurrence and changes in species composition at different location varied.Thirty-four soil samples were ana- lyzed for chemical properties of the soils of Schirmacher Oasis and Nunatak,East Ant- arctica.The most common plant species growing throughout the areas of Schirmacher Oasis and Nunataks are:Candelariella flava (lichen) and Bryum pseudotriquetrum (moss).Large variations were observed among different soil samples in all the nutri- ents and other measured soil chemical parameters.The soils are characterized by a- cidic pH ranging from 4.42-6.80.The mean organic carbon content was 0.62 and ranged from 0.06-1.29%.The electrical conductivity in 1:2 soil water ratio ranged from 0.06-1.29.The average content of macronutrient cation,which are ammonium acetate extractable was in the order of Ca>K>Na>Mg.The average content of DTPA extractable micronutrient cations was in the order of Fe>Mn>Cu>Zn.Thirty one out of 34 samples contained less than 0.80 ppm DTPA extractable Zn. Correlation studies revealed that content of macronutrient cations significantly and positively correlated to that of chlorides.Electrical conductivity exhibited significant and positive relationship with pH,K,Ca,Mg,Na and chloride content.Sodium (r =0.876~(**)) exhibited highest correlation followed by K (r=0.831~(**)) with chlo- ride content.The correlation coefficient for chlorides was higher with electrical con- ductivity (r=0.732~(**)) than pH (r=0.513~(**)).Organic carbon content of the soil was positively correlated with Fe (r=0.442~*).The nutrient status did not ap- pear to be a limiting factor in growth of plants.Lichen and moss community structure and composition in the study area were not related with fertility status of soil.Terres- trial mosses are most abundant and luxuriant along the soil habitats near bank of water bodies and the melt water streams.  相似文献   

11.
Understanding biogeographic patterns and the mechanisms underlying them has been a main issue in macroecology and biogeography, and has implications for biodiversity conservation and ecosystem sustainability. Evergreen broad-leaved woody plants(EBWPs) are important components of numerous biomes and are the main contributors to the flora south of 35°N in China. We calculated the grid cell values of species richness(SR) for a total of 6265 EBWP species in China, including its four growth-forms(i.e., tree, shrub, vine, and bamboo), and estimated their phylogenetic structure using the standardized phylogenetic diversity(SPD) and net relatedness index(NRI). Then we linked the three biogeographical patterns that were observed with each single environmental variable representing the current climate, the last glacial maximum(LGM)–present climate variability, and habitat heterogeneity, using ordinary least squares regression with a modified t-test to account for spatial autocorrelation. The partial regression method based on a general linear model was used to decompose the contributions of current and historical environmental factors to the biogeographical patterns observed. The results showed that most regions with high numbers of EBWP species and phylogenetic diversity were distributed in tropical and subtropical mountains with evergreen shrubs extending to Northeast China. Current mean annual precipitation was the best single predictor. Topographic variation and its effect on temperature variation was the best single predictor for SPD and NRI. Partial regression indicated that the current climate dominated the SR patterns of Chinese EBWPs. The effect of paleo-climate variation on SR patterns mostly overlapped with that of the current climate. In contrast, the phylogenetic structure represented by SPD and NRI was constrained by paleo-climate to much larger extents than diversity, which was reflected by the LGM–present climate variation and topog-raphy-derived habitat heterogeneity in China. Our study highlights the importance of embedding multiple dimensions of biodiversity into a temporally hierarchical framework for understanding the biogeographical patterns, and provides important baseline information for predicting shifts in plant diversity under climate change.  相似文献   

12.
Yang  Fan  He  Fanneng  Li  Meijiao  Li  Shicheng 《地理学报(英文版)》2020,30(7):1083-1094
Global historical land use scenarios are widely used to simulate the climatic and ecological effects of changes in land cover; however, reliability evaluation of these scenarios for data on China's forests is missing. By using a historical document-derived Chinese forest dataset(CHFD) for the years 1700–2000, we evaluated the reliability of data on forests in China over three global scenarios—SAGE(Center for Sustainability and the Global Environment), PJ(Pongratz Julia), and KK10(Kaplan and Krumhardt 2010)—through trend-related, quantitative, and spatial comparisons. The results show the following:(1) Although the area occupied by forests in China in the SAGE, PJ, KK10, and CHFD datasets decreased over the past 300 years, there were large differences between global scenarios and CHFD. The area occupied by forests in China in the SAGE scenario for 1700–1990 was 20%–40% more than that according to CHFD, and that occupied by forests in the KK10 from 1700 to 1850 was 32%–46% greater than that in CHFD. The difference between the PJ and CHFD was lower than 20% for most years.(2) Large differences were detected at the provincial and grid cell scales, where the PJ scenario was closer to CHFD in terms of total forested area. Provinces with large differences in terms of trend and quantity were 84% and 92% of all provinces, respectively. Grid cells with relative differences greater than 70% accounted for 60%–80% of all grids.(3) These global historical land use scenarios do not accurately reveal the spatiotemporal pattern of Chinese forests due to differences in the data sources, methods of reconstruction, and spatial scales.  相似文献   

13.
Quantifying correlation between the spatial patterns of natural wetland plants and environmental gradient gives better understanding of wetland habitats, which is the fundamental for the strategy making on the protection and restoration of natural wetlands. In this study, the spatial patterns of wetland plants and the environmental gradient of wetland habitats were assessed in the Honghe National Nature Reserve (HNNR) in Northeast China, a wetland of international importance on the Ramsar list. Biophysical parameters’ values of wetland plants were obtained by field sampling methods, and wetland mapping at the community scale was completed using remote sensing techniques. Digital delineation of the surface water system, hydrological zoning and wetness index were produced by spatial analysis methods in Geographic Information System. An ecological ordination method and two clustering methods were used to quantify the relationship between the spatial distribution patterns of wetland plants and the corresponding environmental gradients. Such quantitative analyses also present the specific diversity of different types of wetland plants based on the environmental attributes of their habitats. With the support from modern geo-information techniques, the experimental results indicate how four ecotypes of wetland plants spatially transit from forest swamp, shrub wetland and meadow into marsh wetland with increasing wetness index and water table. And they also show how wetland spatial distribution patterns are controlled by an environmental gradient of wetness. Another key finding of this research work is that our results present the exact fundamental differences between marsh and non-marsh plants of 11 wetland plant communities within the core study area. Hence, this case study gives a good sample for better understanding of the complex correlation between the spatial patterns of wetland plants and their environmental attributes using advanced digital analysis methods. It is also useful to show how to integrate geoinformatic techniques with statistical analysis methods based on the field data base.  相似文献   

14.
Plant communities were sampled in the lower reaches of the Tarim River,Xinjiang,The results showed that there are 23 species belonging to 21 genera in 11 families,most of which have low occurrence frequency in quadrats.The most common species is Tamarix ramosissima,which occurred in 17 sites accounting for 89.47% of the total 19 sites,Quantitative classification (TWINSPAN) and ordination(CCA) methods were used to study the distribution Patterns of 23 plant species in 19 sites in this valley.TWINSPAN results showed that the plant communities in the middle reaches of the Tarim River could be divided into 3 groups and the sampling sites could be diveded into 7 types in 3 groups .CCA results were consistent with TWINSPAN results ,and showed species distribution patterns correlated with major environmental variables of groundwater level and soil moisture.  相似文献   

15.
The retreating snowfields and glaciers of Glacier National Park, Montana, USA, present alpine plants with changes in habitat and hydrology. The adjacent and relic periglacial patterned ground consists of solifluction terraces of green, vegetation-rich stripes alternating with sparsely vegetated brown stripes. We established georeferenced transects on striped periglacial patterned ground for long-term monitoring and data collection on species distribution and plant functional traits at Siyeh Pass and at Piegan Pass at Glacier National Park. We documented species distribution and calculated the relative percent cover(RPC) of qualitative functional traits and used 16 S rRNA from soil samples to characterize microbial distribution on green and brown stripes. Plant species distribution varied significantly and there were key differences in microbial distribution between the green and brown stripes. The rare arctic-alpine plants Draba macounii, Papaver pygmaeum, and Sagina nivalis were restricted to brown stripes, where the RPC of xeromorphic taprooted species was significantly higher at the leading edge of the Siyeh Pass snowfield. Brown stripes had a higher percentage of the thermophilic bacteria Thermacetogenium and Thermoflavimicrobium. Green stripes were co-dominated by the adventitiously-rooted dwarf shrubs Salix arctica and the possibly N-fixing Dryas octopetala. Green stripes were inhabited by Krummholz and seedlings of Abies lasiocarpa and Pinus albicaulus. Prosthecobacter, a hydrophilic bacterial genus, was more abundant on the green stripes, which had 6,524 bacterial sequences in comparison to the 1,183 sequences from the brown stripes. While further research can determine which functional traits are critical for these plants, knowledge of the current distribution of plant species and their functional traits can be used in predictive models of the responses of alpine plants to disappearing snowfields and glaciers. This research is important in conservation of rare arctic-alpine species on periglacial patterned ground.  相似文献   

16.
Energy eco-efficiency is a concept integrating ecological and economic benefits arising from energy utilization and serves as a measure of efficiency in the energy–environment–economy system. Using the slacks-based measure(SBM) model considering undesirable output, this study first measures the energy eco-efficiency of provinces in China from 1997 to 2012. It then analyzes the spatial distribution and evolution of energy eco-efficiency from three aspects: scale, intensity, and grain of spatial patterns. Finally, it examines the spatial spillover effects and influencing factors of energy eco-efficiency in different provinces by means of a spatial econometric model. The following conclusions are drawn:(1) The overall energy eco-efficiency is relatively low in China, with energy-inefficient regions accounting for about 40%. Guangdong, Hainan and Fujian provinces enjoy the highest energy eco-efficiency, while Ningxia, Gansu, Qinghai, and Xinjiang are representative regions with low efficiency. Thus, the pattern of evolution of China's overall energy eco-efficiency is U-shaped. Among local regions, four main patterns of evolution are found: increasing, fluctuating, mutating, and leveling.(2) At the provincial level, China's energy eco-efficiency features significant spatial agglomeration both globally and locally. High–high agglomeration occurs mainly in the eastern and southern coastal regions and low–low agglomeration in the northwestern region and the middle reaches of the Yellow River. Changes in spatial patterns have occurred mainly in areas with high–low and low–high agglomeration, with the most remarkable change taking place in the Beijing–Tianjin–Hebei region.(3) There exist significant spatial effects of energy eco-efficiency among provinces in China. For the energy eco-efficiency of a given region, spatial spillovers from adjacent regions outweigh the influence of errors in adjacent regions. Industrial structure has the greatest influence on energy eco-efficiency.  相似文献   

17.
How species diversity–productivity relationships respond to temporal dynamics and land use is still not clear in semi-arid grassland ecosystems. We analyzed seasonal changes of the relationships between vegetation cover, plant density, species richness, and aboveground biomass in grasslands under grazing and exclosure in the Horqin Sandy Land of northern China. Our results showed that in grazed and fenced grassland, vegetation cover, richness, and biomass were lower in April than in August, whereas plant density showed a reverse trend. Vegetation cover during the growing season and biomass in June and August were higher in fenced grassland than in grazed grassland, whereas plant density in April and June was lower in fenced grassland than in grazed grassland. A negative relationship between species richness and biomass was found in August in fenced grassland, and in grazed grassland the relationship between plant density and biomass changed from positive in April to negative in August. The relationship between the density of the dominant plant species and the total biomass also varied with seasonal changes and land use (grazing and exclosure). These results suggest that long-term grazing, seasonal changes, and their interaction significantly influence vegetation cover, plant density, and biomass in grasslands. Plant species competition in fenced grassland results in seasonal changes of the relationship between species richness and biomass. Long-term grazing also affects seasonal changes of the density and biomass of dominant plant species, which further affects the seasonal relationship between plant density and biomass in grasslands. Our study demonstrates the importance of temporal dynamics and land use in understanding the relationship between species richness and ecosystem function.  相似文献   

18.
Alluviation and sedimentation of the Yellow River are important factors influencing the surface soil structure and organic carbon content in its lower reaches. Selecting Kaifeng and Zhoukou as typical cases of the Yellow River flooding area, the field survey, soil sample collection, laboratory experiment and Geographic Information System(GIS) spatial analysis methods were applied to study the spatial distribution characteristics and change mechanism of organic carbon components at different soil depths. The results revealed that the soil total organic carbon(TOC), active organic carbon(AOC) and nonactive organic carbon(NOC) contents ranged from 0.05–30.03 g/kg, 0.01–8.86 g/kg and 0.02–23.36 g/kg, respectively. The TOC, AOC and NOC contents in the surface soil layer were obviously higher than those in the lower soil layer, and the sequence of the content and change range within a single layer was TOCNOCAOC. Geostatistical analysis indicated that the TOC, AOC and NOC contents were commonly influenced by structural and random factors, and the influence magnitudes of these two factors were similar. The overall spatial trends of TOC, AOC and NOC remained relatively consistent from the 0–20 cm layer to the 20–100 cm layer, and the transition between high-and low-value areas was obvious, while the spatial variance was high. The AOC and NOC contents and spatial distribution better reflected TOC spatial variation and carbon accumulation areas. The distribution and depth of the sediment, agricultural land-use type, cropping system, fertilization method, tillage process and cultivation history were the main factors impacting the spatial variation in the soil organic carbon(SOC) components. Therefore, increasing the organic matter content, straw return, applying organic manure, adding exogenous particulate matter and conservation tillage are effective measures to improve the soil quality and attain sustainable agricultural development in the alluvial/sedimentary zone of the Yellow River.  相似文献   

19.
Arbuscular mycorrhizal fungi(AMF) are universally mutualistic symbionts that colonize the fine roots of most vascular plants. However, the biogeographical patterns and driving factors of AMF diversity of plant roots in grasslands are not well investigated. In this study, we used high-throughput sequencing techniques and bioinformatics to evaluate the AMF richness of 333 individual plant roots in 21 natural grassland ecosystems in northern China, including the Loess Plateau(LP), the Mongolian Plateau(MP), and the Tibetan Plateau(TP). The AMF richness showed a significant parabolic trend with increasing longitude. In regional situations, the AMF richness in the grasslands of the MP(60.4 ± 1.47) was significantly higher than those of the LP(46.4 ± 1.43) and TP(44.3 ± 1.64). Plant traits(including plant families, genera, and functional groups) explained the most variation in the AMF richness across China's grasslands, followed by energy and water; soil properties had the least effects. The results showed the biogeographical patterns of the AMF richness and the underlying dominant factors, providing synthetic data compilation and analyses in the AMF diversity in China's grasslands.  相似文献   

20.
Vegetation biomass is an important component of terrestrial ecosystem carbon stocks. Grasslands are one of the most widespread biomes worldwideplaying an important role in global carbon cycling. Thereforestudying spatial patterns of biomass and their correlations to environment in grasslands is fundamental to quantifying terrestrial carbon budgets. The Eurasian steppean important part of global grasslandsis the largest and relatively well preserved grassland in the world. In this studywe analyzed the spatial pattern of aboveground biomass(AGB)and correlations of AGB to its environment in the Eurasian steppe by meta-analysis. AGB data used in this study were derived from the harvesting method and were obtained from three data sources(literatureglobal NPP database at the Oak Ridge National Laboratory Distributed Active Archive Center(ORNL)some data provided by other researchers). Our results demonstrated that:(1) as for the Eurasian steppe overallthe spatial variation in AGB exhibited significant horizontal and vertical zonality. In detailAGB showed an inverted parabola curve with the latitude and with the elevationwhile a parabola curve with the longitude. In additionthe spatial pattern of AGB had marked horizontal zonality in the Black Sea-Kazakhstan steppe subregion and the Mongolian Plateau steppe subregionwhile horizontal and vertical zonality in the Tibetan Plateau alpine steppe subregion.(2) Of the examined environmental variablesthe spatial variation of AGB was related to mean annual precipitation(MAP)mean annual temperature(MAT)mean annual solar radiation(MAR)soil Gravel contentsoil p H and soil organic content(SOC) at the depth of 0–30 cm. NeverthelessMAP dominated spatial patterns of AGB in the Eurasian steppe and its three subregions.(3) A Gaussian function was found between AGB and MAP in the Eurasian steppe overallwhich was primarily determined by unique patterns of grasslands and environment in the Tibetan Plateau. AGB was significantly positively related to MAP in the Black Sea-Kazakhstan steppe subregion(elevation 3000 m)the Mongolian Plateau steppe subregion(elevation 3000 m) and the surface(elevation ≥ 4800 m) of the Tibetan Plateau. Neverthelessthe spatial variation in AGB exhibited a Gaussian function curve with the increasing MAP in the east and southeast margins(elevation 4800 m) of the Tibetan Plateau. This study provided more knowledge of spatial patterns of AGB and their environmental controls in grasslands than previous studies only conducted in local regions like the Inner Mongolian temperate grasslandthe Tibetan Plateau alpine grasslandetc.  相似文献   

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