Spatial analysis of rangeland's vegetation intensity as related to selected physical soil variables over ABQAIQ municipality of Saudi Arabia

Through most of the natural rangelands of Saudi Arabia, overgrazing, sand drifting, and off-road vehicles driving are almost the major contributing factors that lead to vegetation damage and land degradation in natural landscapes. The current study aimed at examining the dynamic nature of Abqaiq rangelands' vegetation, generating a vegetation intensity map, and investigating possible impacts caused by the spatial variability of obtained soil texture, sand content (%), and the derived available water capacity (DAW capacity (%)) on the intensity distribution of vegetation cover. Ordinal-nominal correlation type and spatial autocorrelation processes were adopted throughout the study to analyze the spatial correspondences as well as the interrelated patterns of the given variables. The resultant correlation between vegetation and soil texture (ordinal versus nominal variables) has yielded a significant (p-value < 0.001) relevancies, where, silt loam texture class, in particular, has proven to have the most correlated values to the most intensive vegetation habitats, where 5%, 35%, and 28% of the silt loam class were occupied by 80%, 60%, and 40% of vegetation intensities, respectively. Whereas, for the continuous variables, correlation outcomes have achieved a substantial negative spatial autocorrelation concerning vegetation intensity and sand content percentage, revealing a total absence of green biomass over the sandy soils. Additionally, vegetation intensity versus DAW capacity percentage significantly yielded a positive autocorrelation, revealing a high clustering of green biomass cover that associates with high clustering of high-water capacity soils. The autocorrelation strength identifier (Morn's I), produced an approximate value of 0.3 with a pseudo p-value of 0.001, for both relationships. The findings of this study would help researchers and relative authorities to grasp the reasons, consequences and behaviors of rangeland flora, considering Abqaiq's area as an example.     

Trace Element Concentration in Hair Samples as an Indicator of Exposure of Population in the Negev, Israel

The concentration of the toxic elements Ag, As, Cd, Co, Mn, Mo, Pb, Se, and U and the elements Al, Mg, Cu, Fe, and Zn in human hair samples of population living in the north of the Negev Desert in Israel was determined. The study population consisted of three subgroups: Jewish urban population, Bedouin urban population, and Bedouins living in unrecognized villages (the “dispersion”). The main focus is on the differences between these subgroups in an attempt to explore factors responsible for the variation in trace metal contents in hair samples. The results show that the level of several elements, particularly Ag, Mn, and Pb, in the female Bedouin group significantly differed from the other groups in the study. Exploring the reasons for these differences, we concluded that the lifestyle of those women is the main cause. The female Bedouin subgroup is exposed to heavy metals from kitchen utensils, jewelry, and makeup. Therefore, differences in the heavy metal concentration in the hair samples of this group were attributed to the traditional unique lifestyle and social behavior of the females in the Bedouin society.     

宁夏东部风沙区沙化草地土壤水分和植被的空间特征

土壤水分作为土壤-植被-大气连续体的关键因子,对沙化草地的演化过程具有重要作用。为探讨宁夏东部风沙区沙化草地土壤水分、物种丰富度指数及植被盖度的空间变异及其相互关系,以哈巴湖自然保护区沙化草地为对象,采用样线法自潜在沙化草地至重度沙化草地进行植被调查和土壤取样,通过经典统计学和地统计学分析,得出以下结果：0—100 m各土层土壤水分含量、植被盖度和物种丰富度指数的分布范围分别为0.82%—28.22%、41.00%—93.00%和0.82—2.80,变异系数范围为0.20—0.48,均属于中等变异。各土层土壤水分和物种丰富度指数表现为中等的空间自相关性,植被盖度则表现为强烈的空间自相关性。Kriging插值结果表明,0—100 cm各土层土壤水分和植被盖度的空间插值图呈条带状和斑块状的梯度变化,物种丰富度呈斑块分布,自潜在沙化草地至重度沙化草地,表现为逐渐降低的趋势。相关分析表明,植被盖度与0—40 cm各土层土壤水分呈显著正相关,与40—100 cm各土层土壤水分呈极显著正相关。宁夏东部风沙区沙化草地土壤水分含量总体较低,由于结构因素和随机因素的共同作用,随草地沙化程度的加重,表现为...     

干旱荒漠区植物生态位对水盐的响应

全球气候变化对生态系统功能的影响决定着种群地位和群落演替,由于干旱区的特殊性成为研究生物响应环境变化的热点地区。为探索艾比湖流域荒漠区植物生态位对土壤水盐梯度的响应,在研究水、盐含量和植物生态位特征的基础上,应用变系数模型,分析了土壤水盐梯度下的群落组成和生态位响应趋势。结果显示:(1)随土壤水盐梯度的降低,艾比湖流域群落的物种组成呈倒"V"型分布,说明土壤水盐交互作用影响着植被分布和群落类型。(2)高水盐环境下,胡杨(Populus euphratica)、琵琶柴(Reaumuria soongorica)和梭梭(Haloxylon ammodendron)等生态位宽度值(B_i)较大,柽柳(Tamarix ramosissima)、骆驼刺(Alhagi sparsifolia)和甘草(Glycyrrhiza uralensis)等B_i较小;中水盐环境下,白刺(Nitraria schoberi)和琵琶柴的B_i较大,铃铛刺(Halimodendron halodendron)、甘草和盐节木(Halocnemum strobilaceum)的B_i较小;低水盐环境下,梭梭、花花柴(Karelinia caspica)和琵琶柴等B_i较大,盐节木的B_i较小;说明土壤水盐环境和物种生态学特性是影响B_i的重要因素。(3)物种水平上,B_i较大的种群与其他物种的生态位重叠(O_(ij))一般较大,但B_i较小的物种间的O_(ij)不一定小(例如:高水盐土壤环境下柽柳和骆驼刺的O_(ij)为1);群落水平上,B_i与O_(ij)具有一定的正相关性;说明由于资源纬度的相似性增大了低B_i物种间的O_(ij),并且B_i和O_(ij)由物种向群落尺度转换时,两者之间的关系存在冗余。(4)土壤水盐梯度与群落生态幅呈现一种非线性相关特征,高水盐格局对群落B_i有一定的促进效应,而低水盐模式对B_i具有一定的限制作用,表明土壤水盐的协同效应影响着物种在群落的地位,并在一定程度上决定了群落向正负两极演替的方向。     

Annual plant community responses to density of small-scale soil disturbances in the Negev Desert of Israel

We investigated whether plant diversity and productivity in small-scale soil disturbances, which is known to be higher than in undisturbed soil, decreases as the density of the disturbances increases. We studied this in an experiment with soil diggings (15 cm diameter and 15 cm depth) dug at a range of densities, on a north- and a south-facing slope of a watershed in the central Negev Desert of Israel. The diggings were similar to the commonly occurring pits made by porcupines (Hystrix indica) as they forage for below-ground plant parts. We used four levels of digging density, within the naturally occurring range in the region, represented by a rectangular plot with rows of diggings dug at four distances between diggings. The plots were laid out in a blocked design with three replications on both slopes, with each block containing all four levels of digging density. In the spring of 1992, 1994 and 1995 we measured plant density, species richness and plant productivity in the diggings, and in adjacent equal-sized undisturbed control areas (“soil matrix”) and on the mounds made by the removed excess soil. Plant density, species richness and productivity of annual plants were higher in the diggings than in the undisturbed matrix, while these responses were very low on the mounds. Plant density, species richness and productivity in the diggings, but not in the matrix or mounds, decreased as digging density increased. This effect varied slightly with location within a watershed and with annual rainfall. The density of seeds captured in the diggings from outside the digging during the 1995 dispersal season decreased with increasing digging density, but only on one of the slopes. At the highest digging density, plant density and species number in the diggings did not decrease down the slope, as expected if interference between diggings in runoff water capture were the cause of the digging density effect. There was a weak decrease in biomass production in 1994–1995 down the slope. We used a simple mathematical model to estimate whether the distribution of rainfall intensities that occurred during the winter of 1994–1995 could result in differences between digging densities in the amount of water captured by the diggings, and whether this could explain the observed effect of digging density. The model showed that there were four events during which less water was captured by the diggings at high digging densities, except in the topmost row of diggings. Soil moisture measurements, however, showed very little difference between diggings at different digging densities. We explain our findings as the result of the interaction between the properties of the disturbance patch with its surroundings, as the diggings capture resources in the form of runoff water, and seeds moved primarily by wind. The additional resources and seeds captured in diggings increase plant density, species richness and productivity relative to the undisturbed matrix. However, the contrast in plant responses between the disturbed patches and undisturbed soil diminishes at higher digging densities. We explain this as interference among diggings at close proximity. As we did not detect a decrease in plant responses down the slopes, we conclude that interference is due to interception of the wind-driven, non-directional flow of seeds. Interception of the down-slope flow of runoff water by upslope diggings is insufficient to affect plant density, determined at the beginning of the season. Later in the season, runoff interception may become important for biomass production. Received: 16 August 1996 / Accepted: 26 October 1997     

Role of seed bank in aboveground vegetation regeneration signal ecosystem transition from arid grassland to shrubland with decreasing soil moisture

Plant and Soil - This study aimed to evaluate the role of seed bank during ecosystem transitions from arid grassland to shrubland. We explored the aboveground vegetation, seed bank and soil...     

Vertical distribution of the free-living amoeba population in soil under desert shrubs in the Negev desert, Israel

A field study was designed to examine the effect of desert shrubs on the dynamics of free-living amoebae in arid soil. Soil samples from 0- to 50-cm depths were collected at 10-cm intervals in each of the four seasons. The vertical distributions of the four main morphological types of amoebae, grouped according to their mobility, and of small flagellate populations were measured under the canopies of Hammada scoparia and Atriplex halimus, shrubs belonging to the chloride-absorbing xerohalophytes. The result obtained from the field study demonstrated that the total number of protozoa was significantly higher during the wet seasons (winter and spring) than during the dry seasons. The protozoan population was more diverse under the canopy of H. scoparia during the wet seasons, reaching 8,000 individuals per 1 g of dry soil, whereas during the dry seasons, the populations were higher under the canopy of A. halimus, with a mean of 250 individuals. The protozoan population in the deeper layers (40 to 50 cm) was found to be as active as that in the upper layers, demonstrating that, in the desert, soil columns below 20 cm are fertile and worth studying. The type 1 amoebae (e.g., Acanthamoeba and Filamoeba spp.) were the most abundant throughout the study period, and their numbers were significantly higher than those of the other amoeba types.     

Spatial structure of community of darkling beetles (Coleoptera: Tenebrionidae) in the Negev Highlands, Israel

The distribution of niches in resource space of darkling beetles of Negev desert, Israel were studied using discriminant analysis Seventeen environmental variables (substrate structure and vegetation) were measured at 375 plots within 15 grids The first three discriminant axes account for 77% of the variance and reflect a soil structure gradient from sand to clay (the first axis), a gradient of increasing productivity (the second axis), and a type of vegetation architecture (the third axis) Abundance and biomass of tenebrionids increased linearly along the first, the second and the third axes Species richness and diversity had a slanting parabola shape along the substrate axis and increased along the productivity axis There were two distinct spatial guilds of tenebrionid species One guild was composed by species that preferred sandy-gravel soils, and another guild consisted of species that preferred clay soils Niche overlapping of the "sandy-gravel" species was lower than that of the "clay" species Niches of the "sandy-gravel" species were randomly distributed in the resource space Those of the "clay" species formed a tight cluster with most niches placed in the center of the space, representing the centrifugal type of organization The conformity of the guild structure with the different types of organization was supported by compansons between empirical data and stochastic models The border between these two guilds matches with proposed earlier biogeographical boundary (Ramon-Zohar line)     

Climate change and hydrological regime in arid lands: Impacts of dams on the plant diversity,vegetation structure and soil in Saudi Arabia

As the direct effects of climate change on the hydrological regime, Saudi Arabia has constructed more than 522 dams of various capacities as part of economic and environmental development. The study aims to assess the impact of dams on plant diversity, vegetation structure and soil in Saudi Arabia. Thirty-five stands were selected from the dams of different sizes of Saudi Arabia. Vegetation samples were established before (upstream) and after (downstream) the dam, and at the undammed (unaffected by the dam) to compare species diversity in the dam sites and undammed sites and to document the potential effects of dams on vegetation structure. A total of 151 plant species belonging to 36 families have been recorded. The vegetation associations are essentially shrubby with widespread annuals. Six novel associations were identified with the application of TWINSPAN, DCA, and CCA programs. They were named after the characteristic species as follows: VG I: Acacia gerrardii-Caralluma retrospiciens; VGII: Acacia tortilis-Maerua oblongifolia; VGIII: Lycium shawii-Farsetia aegyptiaca; VG IV: Farsetia stylosa-Cornulaca monocantha; VG V: Suaeda aegyptiaca-Salsola imbricata-Prosopis farcta and VGVI: Xanthium strumarium-Ochradenus baccatus. These plant communities are evaluated and discussed according to their floristic structure, vegetation diversity and edaphic variables. The riparian or streamside zones upstream and downstream that are periodically flooded contain highly diverse plant communities that are structured by flooding, which creates disturbance and acts as a dispersal mechanism for plants than undammed sites.     

黑河中游荒漠绿洲过渡带土壤水分与植被空间变异

荒漠绿洲过渡带是绿洲生态系统的重要组成部分,对维持绿洲稳定具有重要作用。过渡带土壤湿度和植被之间的相互关系是了解荒漠绿洲过渡带的重要科学问题,从而开始受到重视。研究是在黑河中游荒漠绿洲过渡带,选择一条1700m×200m的样带（包括3条平行样线）,在对土壤湿度、植被高度、盖度等调查的基础上,应用统计分析和地统计的方法,研究了荒漠绿洲过渡带土壤水分和植被的空间变异性特征。结果表明：在荒漠绿洲过渡带上,0～200cm土层中土壤平均湿度介于1．45％～3．85％,变异系数在27．7％～83．2％;植被盖度介于9％～80％,变异系数为80％。植被盖度、冠幅与0～20、20～40cm两层土壤湿度显著负相关（p〈0．05）,与120～140、140～160cm两层土壤湿度显著正相关（p〈0．01）。土壤水分和植被空间分布在样带上存在明显的空间异质性,表现在小于100m的尺度上随机分布,而在100～3110m的尺度上呈聚集分布格局。     

Growth and reproductive responses to elevated CO2 in wild cereals of the northern Negev of Israel

How might wild relatives of modern cereals have responded to past, and how might they respond to future, atmospheric CO₂ enrichment under competitive situations in a dry, low‐nutrient environment? In order to test this, Aegilops and Hordeum species, common in semiarid annual grasslands of the Middle East, were grown in nine model ecosystems (400 kg each) with a natural matrix of highly diverse Negev vegetation established on native soil shipped to Basel, Switzerland. In a simulated, seasonally variable climate of the northern Negev, communities experienced a full life‐cycle in 280 (preindustrial), 440 (immediate future) and 600 ppm of CO₂ (end of the next century). Neither Aegilops (A. kotschyi and A. peregrina), nor Hordeum spontaneum showed a significant biomass response to CO₂ concentrations exceeding 280 ppm The reproductive output remained unaffected or even declined (A. peregrina) under elevated CO₂. Non‐structural carbohydrates in leaf tissues increased and N concentration decreased with increasing CO₂ concentration. N concentration, germination success and seedling development of newly formed grains were either unchanged or reduced in response to high CO₂ treatment of parent plants. In a separate fertilizer × CO₂ trial with A. kotschyi nested in smaller model communities, we found no effect of P addition, but a 2–3‐fold biomass increase by NPK addition compared to the unfertilized control. A significant stimulation of biomass by CO₂ enrichment (+ 44% between 280 and 600 ppm) was obtained only in the NPK treatment. These data suggest that increased CO₂ concentration had little direct effect on growth and reproduction in these ‘wild cereals’ in the recent past, and the same seems to hold for their future, except if N‐rich fertilizer is added.     

亚热带典型红壤侵蚀区人类活动对植被覆盖度及景观格局的影响

福建省长汀县是中国南方最严重的水土流失区之一,在20世纪80年代初和2000年两次集中治理的推动下,当地生态环境已得到显著改善。基于Landsat系列卫星影像提取长汀县1975—2013年共6期植被覆盖度分布图,分析该区在不同时期植被覆盖度及其空间格局的时空动态,并探讨人类干扰与政策治理对植被覆盖度及景观格局的影响。结果表明:(1)近38年来,长汀县平均植被覆盖度由47.02%(1975)提升至71.47%(2013),在覆盖度结构上逐渐形成以中高和高植被覆盖度占主导的格局;县域中部河田盆地的植被覆盖度由30.83%(1975)提升至60.34%(2013)。(2)在景观格局上,研究期间长汀县极低、低和中低覆盖度斑块平均面积呈波动下降趋势、同时斑块密度增加,而中高、高植被覆盖度区域面积扩大,表明封禁、造林等治理措施导致植被覆盖度较高的区域不断汇聚成片。(3)植被覆盖度的提升在空间上主要集中在海拔600 m和坡度25°以下区域,尤其在海拔400—600 m和坡度5°—15°区域最显著,表明植被的破坏和恢复过程与人类活动的联系密切。(4)空间分析表明,在距离农户居民地边缘1.2 km的范围内,越接近居民地中心的区域植被覆盖度越低、破碎度越大且恢复缓慢,但这种空间差异伴随治理进行正在逐步减弱。总体上看,长汀县生态治理和人类干扰的长期驱动影响,其恢复速度在不断提升。     

祁连山地甘肃臭草斑块土壤水分与植被盖度空间格局

土壤水分是植被格局形成和演变的主要因素,土壤水分的空间异质性对于认识干旱区草原植物对环境的响应机制具有重要意义,而在较小尺度上,植被状况是土壤水分空间异质性的主要驱动因子.利用地统计学方法,研究了祁连山北坡甘肃臭草单优种群斑块浅层剖面(0 ～30 cm)土壤水分与植被盖度的空间异质性及其关系.结果表明:甘肃臭草斑块浅层剖面土壤水分和植被盖度均符合正态分布,各层土壤水分均存在高度的空间异质性,其中,80.93％～87.34％的空间异质性是由空间自相关引起的,植被盖度主要体现在4.09～6.91 m的尺度上,而由1 m以下尺度随机因素引起的空间异质性占12.66％ ～19.07％;甘肃臭草在斑块尺度上各层土壤水分的空间结构表现出明显的圈层结构和斑块状分布的特点,土壤水分高低值斑块呈镶嵌分布且具有较强的空间异质性;甘肃臭草通过生理整合影响并在一定程度上改变了小尺度上土壤水分的分布格局,从而实现了对土壤水分资源最大限度的利用,提高了种群在干旱生境中的适应能力和竞争力.     

毛乌素沙地南缘沙漠化临界区域土壤水分和植被空间格局

应用地统计学和经典统计学方法,对毛乌素沙地南缘沙漠化临界区域土壤水分和植被特征的空间分布格局及其相互关系进行研究,结果表明: 0-5 cm和5-10 cm土壤水分符合指数模型,10-15 cm土壤水分和植物群落物种数、植被盖度、植被密度都符合球状模型;0-5 cm土壤水分、植物群落物种数和植被盖度都具有强空间自相关性,5-10 cm、10-15 cm土壤水分和植被密度都具有中等程度的空间自相关性;从牛枝子群落到黑沙蒿群落,各层土壤水分与植物群落物种数之间具有相似的空间格局,都呈先升高后降低的变化趋势,而植被盖度和植被密度呈逐渐减小的变化趋势;0-5 cm土壤水分与植物群落物种数之间具有显著的正相关,是制约植被物种空间分布的关键因素。     

Leaf gas exchange in a clonal eucalypt plantation as related to soil moisture, leaf water potential and microclimate variables

In order to determine how environmental and physiological factors affect leaf gas exchange in a 9-year-old clonal eucalypt plantation (Eucalyptus grandis Hill ex. Maiden hybrids) in the State of Espirito Santo, Brazil, the diurnal patterns of predawn leaf water potential (Ψ_pd), and leaf gas exchange were monitored from November 1995 to August 1996. Soil water content (Θ) and microclimatic variables were also recorded. Most of the rainfall during the experimental period occurred from October to December 1995 and from March to April 1996, causing a significant variation in Θ and Ψ_pd. A high positive correlation (r ²=0.92) was observed between Ψ_pd and Θ measured at 0.3 m depth from the soil surface. During conditions of high soil water availability, the maximum values of stomatal conductance for water vapor (g _s) and net photosynthetic rate (A) were over 0.4 mol m^–2 s^–2 and l5 μmol m^–2 s^–1, respectively. The results showed that Ψ_pd and leaf gas exchange of the examined trees were susceptible to changes in the water content of the upper soil layers, where the major concentration of active roots occur. Multiple linear regression analysis indicated that photosynthetic active radiation (Q), vapor pressure deficit (VPD), atmospheric CO₂ molar fraction (C _a), and Ψ_pd were the most important factors controlling g _s whereas Q and VPD were the main microclimatic variables controlling A. Received: 5 November 1998 / Accepted: 10 November 1999     

Small-scale vegetation pattern related to the growth of Lycopodium annotinum and variations in its micro-environment

Small-scale variations in topography, soil depth and species occurrence were studied in a sub-arctic/sub-alpine brich forest in Swedish Lapland in order to evaluate the effects of various micro-habitats on the growth and distribution of Lycopodium annotinum. Micro-topographical variation in the study plot (280 by 420 cm) reached 100 cm, while soil depth varied from 0 to more than 50 cm over small distances of 10's of centimetres. Nineteen species were recorded in the plot and dwarf shrubs and L. annotinum were the most frequent. A micro-scale vegetation pattern was detected by a polythetic agglomerative cluster analysis and also by the divisive TWINSPAN analysis. The distribution patterns of the species appeared to be associated with variation in moisture regimes, which in turn were associated with variations in micro-topography. Lycopodium annotinum performed best when growing on the sides of valleys with deciduous dwarf shrubs and Deschampsia flexuosa, and when evergreen dwarf shrubs were absent.     

塔里木河下游土壤水分与植被时空变化特征

运用变异系数、Pearson相关和回归的方法,分析了塔里木河下游2002-2006年土壤水分的时空变化和植被的分布,以及二者之间的相互关系。结果表明:土壤含水率水平空间分布随离水源地距离增加而降低,垂直分布随土层深度的增加而增加;0-60cm土壤含水率变异性最小,属中等变异性;60cm以下土壤含水量变异性增大,属强变异性;土壤含水率的时间变化受生态输水量和持续时间的制约。土壤含水率与植被的时空分布具有同步性;植被特征指数与80-280cm土壤含水率显著相关,且二者与地下水埋深均呈现极显著负相关,说明60cm以下的土壤含水率显著影响植被的生长和分布,而且地下水位是影响土壤水分和植被时空变异的主要因素。     

Understory vegetation as an indicator of soil characteristics in the Hyrcanian area,N. Iran

The mesic Caspian (Hyrcanian) forest and ecotone communities provide a marked contrast to the arid and semiarid landscapes associated with most of the territory of Iran. To date, the ecological characteristics of these habitats, threatened and of conservation importance, have been little studied. Accordingly, ecological profiles of some important plant species of these communities have been assessed along two altitudinal gradients (300–2300 m a.s.l.). Vegetation and soils were sampled every 100 m in elevation, with the data subsequently analyzed using TWINSPAN and corrected frequency (CF) analyses. Relationships between soil variables (subdivided into three classes, the lowest, the middle and the upper third of all values) and herbaceous and shrub species (presence/absence data) were analyzed by the polythetic divisive classification method. 379 plant species and eleven soil variables – N, P, K, CaCO₃, EC, pH, organic matter, C/N ratio and percentage of sand, clay and silt – were considered. The ecological profile method was used to evaluate the affinity and significance of associations between the probability of species’ occurrence and topsoil characteristics found by the polythetic method. Five vegetation groups were identified: two groups, with Acer campestre and Quercus macranthera in the tree layer and Veronica mazanderanae and Phuopsis stylosa as herbs, were restricted to forest-steppe ecotones and the upper mountain areas. Three groups, with Acer velutinum, Ruscus hyrcanus, Carpinus betulus, Danae racemosa, Fagus orientalis and Aruncus vulgaris as indicator species, occurred in the forest itself. Of the 42 plant species assessed as being of particular importance, 13 had significant relationships with eight soil factors. Thus, certain species, including endemic plant species of restricted distribution and conservation importance, can be used as indicators of particular soil conditions in the Hyrcanian forest area.     

黄土丘陵区地形、土壤水分与草地的景观格局

在黄土丘陵区,地形因素和土壤水分是决定草地景观格局的主要因素,同时草地景观格局在不同尺度上影响着景观中的流.地形因素、土壤水分和草地结构在不同尺度上有着密切的联系,研究它们之间的关系对于了解生态系统的过程十分重要.针对黄土高原异质化的草地群落结构,选取黄土丘陵区经过20多年自然封育形成的天然草地,从坡面尺度对景观格局进行了调查研究,在地形因素、土壤水分和草地结构中选取了有代表性的指标14个,用多元统计分析对选取的指标进行了主成分分析和聚类分析.聚类分析将样方分成3种植被类型,不同植被类型的海拔、坡度、20～140cm土壤含水量以及物种丰富度和生物多样性存在显著性差异.相关分析表明：海拔对0～300cm土壤含水量影响显著;海拔对草地群落盖度,坡位、坡向对草地群落的物种丰富度和生物多样性有着重要影响;而草地群落的物种丰富度和生物多样性与0～100cm土层的含水量关系密切.