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1.
福建柏资源分布的研究   总被引:7,自引:0,他引:7  
福建柏分布范围北纬22°~28°30′,东经102°~120°,中心分布区北纬24°30′26°30′,东经110°~119°,呈间断分布.垂直分布海拔500~1 800 m,往西,往北分布海拔较高,分布范围较窄;往东,往南分布海拔较低,分布范围较宽.分布区属中亚热带湿润气候,中心分布区年平均气温11.7~15℃,年降水量1 600~2 000 mm.分布区土壤主要是花岗岩、砂页岩、板岩发育的山地黄壤和黄棕壤.福建柏为亚热带常绿阔叶林和针阔混交林带天然林重要组成树种,群落类型较丰富.  相似文献   

2.
应用GIS技术,综合统计学和地统计学方法,探讨了浑河太子河流域表层土壤养分的空间分布,同时分析了地形因子、土地利用及其交互作用对土壤养分空间变异的影响。结果表明:海拔、坡度与土壤有机质、全氮、全磷呈极显著正相关,与全钾呈极显著负相关;坡向的影响不显著。林地和草地的有机质、全磷平均含量相对较高;水田和旱地的全钾平均含量较高。地形因子与土地利用方式的交互作用显著影响土壤养分含量。有机质、全氮和全磷含量高的区域集中在海拔较高、坡度较大的林地和草地。地形条件和土地利用方式能够解释研究区土壤养分的空间变异。  相似文献   

3.
皇甫川流域不同尺度景观分异下的土壤性状   总被引:11,自引:0,他引:11  
赵海霞  李波  刘颖慧  张新时 《生态学报》2005,25(8):2010-2018
皇甫川流域地处我国北方农牧交错带中段,是该地区正在进行的国家重点基础规划(“973”)项目设置的范式点之一。按照区域-小流域-中小地形这样的景观分类的等级体系,通过代表小流域的样带设置、实地调查和取样分析等,对该地区区域尺度、流域尺度和中小地形尺度景观分异下的土壤性状进行了分析。在此基础上,对研究区优化生态-生产范式的空间配置问题进行了探讨。结果表明:(1)总体上该研究区土壤养分含量低、发育程度差。(2)不同地质地貌类型区的土壤特性存在差异,黄土丘陵沟壑区的小流域比沙化黄土丘陵区和砒砂岩裸露丘陵沟壑区的小流域的土壤养分和质地好,相对更适于发展耕地。(3)中小地形尺度下,坡向、坡度和坡位及土地利用与土壤性状的关系为:1阴坡和阳坡的土壤有机质含量存在差异显著,且土壤养分还随着坡的向阳程度的减弱而增加。川地的土壤养分也较高,但土壤偏砂性。2坡度与土壤粒径存在显著相关,坡度不同侵蚀强度也不同。15°是侵蚀加剧的临界值,把它作为当地的退耕坡度标准是合理的。3土壤表层养分总体表现为随坡位的下降而减少的趋势。4综合考虑中小地形条件,景观立地类型可以划分为川台地养分富集区,坡中下部养分严重流失区(坡度>15°)和坡梁缓坡地养分涵养区(坡度<15°)。5中小地形尺度下,样带剖面上土地利用变化对土壤性状的影响较大:乔木林土壤养分积累高、团粒结构好,灌木林由于放牧和沙化的影响,土壤养分最低,砂粒含量最高而粘粒含量最低。撂荒地的土壤养分少而农田和果园的土壤养分较高。荒草地的土壤养分条件较差。但就耕地与非耕地而言,土壤养分和质地并无显著差异。说明耕地熟化作用很弱,广种薄收、靠天吃饭现象十分普遍;(4)不同尺度景观分异下的土壤性状研究是优化生态-生产范式的构建的重要理论基础。  相似文献   

4.
基于GIS的缓坡烟田土壤养分空间变异研究   总被引:20,自引:0,他引:20  
综合运用地统计学和GIS相结合的方法,分析了缓坡地形下土壤养分的空间变异规律,并绘制养分空间分布图,为山地缓坡烟田养分分区及精准施肥决策提供理论依据.结果表明:研究区内4种养分含量均具中等程度变异.土壤有机质、碱解氮、速效磷和速效钾的变程分别为61.8、76.3、70.5 m和57 m.土壤速效钾的分形维数最高,有机质和碱解氮其次,速效磷最低.有机质和速效钾的最适模型为指数模型,块金系数分别为30.9%和31.1%;碱解氮和速效磷可用球状模型进行较好拟合,其块金系数分别为37.7%和26.4%,4种养分均有中等程度的空间相关性.各向异性和趋势性分析均显示,有机质和速效磷具有较强的各向异性,碱解氮和速效钾的各向同性范围最广.研究区4种养分的空间分布格局在海拔和坡度的影响下呈现出一定的规律性,低值均在坡度较大的中北部出现,东北部和南部较平缓区域出现高值.  相似文献   

5.
以安顺市至龙天村部分路段位置为基准,选取不同坡度采集距路侧不同距离、高度的油菜及表层土壤样品,测试了各样品中Cu、Pb、Cd、Cr、Zn、Ni、Hg、As元素含量,分析了路侧油菜与土壤中重金属的可能来源、分布规律及表层土壤组成的差异。结果表明:道路截面灰尘有机质含量较高;油菜土壤质地粗细不一,侵入类型以砾石、生活垃圾为主;表层土Cd的Igeo值最高为6.94,属极重污染,Cr、Pb属轻污染;油菜重金属Cd、Cr主要来源地质背景,Pb、Zn、Ni主要受非点源污染源路线影响,Hg、As、Cu与地质背景和人为活动有关;油菜组织重金属含量最大值主要集中在路侧10m内,叶、茎、根中Cr、Cd超标极其严重,分别为:14.49、12.96、15.54倍,35.13、9.54、19.72倍;5m处油菜叶、茎、根对As、Hg、Cr、Pb、Zn、Ni、Cu的富集能力远高于10 m、30 m处。  相似文献   

6.
对咸水灌溉条件下的塔克拉玛干沙漠腹地人工绿地土壤微生物的分布规律和环境因子对土壤微生物分布的影响进行了研究.结果表明,人工绿地建成后,土壤结构和养分状况得到改善,土壤微生物在时间和地域分布上呈现明显的规律性.土壤微生物区系组成中,细菌占绝对优势,放线菌次之,真菌最少;表层微生物数量远多于下层土壤;林地外围距林缘近的土壤微生物数量较多,3m以外微生物数量已接近流沙微生物量;3类土壤微生物分布具有不同的季节性规律,且不同立地类型土壤微生物分布差异显著.土壤速效磷、速效氮、全N对微生物的分布有较大的直接作用,通径系数为1.01~2.58.速效磷-速效钾、有机质-速效钾、速效氮-速效钾、速效氮-效磷速、有机质-速效磷、速效磷-速效氮、全N-速效钾、速效钾-速效磷、全N-速效磷和含水量.速效氮之间的间接作用对微生物影响较明显,作用系数为1.37~2.58。其余因素的作用相对不显著.  相似文献   

7.
利用CASA模型估算植被净初级生产力(NPP)应用广泛,但其精度仍然有待提高。基于地理因子回归方法(AMMRR)和地表水分指数(LSWI)对CASA模型的两个关键参数:温度胁迫系数和水分胁迫系数进行校正,再估算NPP并分析了校正对植被NPP及各因子与NPP关系的影响。研究表明:(1)校正能有效提高CASA模型的估算精度,校正后NPP总量为34.29 TgC/a,原CASA模型高估了0.23 TgC/a。(2)研究不仅可以校正地形对NPP的影响,还可以校正平坦地形下人类活动区NPP的影响;在高海拔、地形起伏较大的区域以及人类活动地区,校正对NPP估算影响较大,绿洲区原模型存在高估。(3)校正对生长季的影响大于非生长季;坡度对NPP影响较大,坡度越大原模型高估越多;校正前高估了阳坡NPP,低估了阴坡NPP。  相似文献   

8.
森林土壤是陆地生态系统的主要碳库,其有机质含量是估算碳储量的基础数据,也是评价土壤碳汇功能的重要指标.利用2009年8月采集的凉水自然保护区激光雷达(LiDAR)数据和55块固定样地土壤有机质含量数据,结合偏最小二乘算法,反演森林表层土壤有机质的空间格局,提取并筛选出与土壤有机质分布相关的变量,分析并确定变量(强度、点数、高程、坡度和坡向)值与土壤有机质含量的相关关系,建立土壤有机质含量的预测模型并检验.结果表明: 研究区域表层土壤有机质含量与强度、点数和高程3变量呈极显著相关(r分别为0.765、0.423和0.475);基于此3变量的预测模型对研究区域表层土壤有机质含量的预测结果可靠(精度83.3%,R2=0.725,RMSE=1.955).研究区林缘和郁闭度较小林分的表层土壤有机质含量<100 g·kg-1;大部分区域表层土壤有机质含量为100~150 g·kg-1,少部分区域为150~318.4 g·kg-1.  相似文献   

9.
基于激光雷达数据的森林表层土壤机质空间格局反演   总被引:1,自引:0,他引:1  
森林土壤是陆地生态系统的主要碳库,其有机质含量是估算碳储量的基础数据,也是评价土壤碳汇功能的重要指标.利用2009年8月采集的凉水自然保护区激光雷达(LiDAR)数据和55块固定样地土壤有机质含量数据,结合偏最小二乘算法,反演森林表层土壤有机质的空间格局,提取并筛选出与土壤有机质分布相关的变量,分析并确定变量(强度、点数、高程、坡度和坡向)值与土壤有机质含量的相关关系,建立土壤有机质含量的预测模型并检验.结果表明:研究区域表层土壤有机质含量与强度、点数和高程3变量呈极显著相关(r分别为0.765、0.423和0.475);基于此3变量的预测模型对研究区域表层土壤有机质含量的预测结果可靠(精度83.3%,R2=0.725,RMSE=1.955).研究区林缘和郁闭度较小林分的表层土壤有机质含量<100 g·kg-1;大部分区域表层土壤有机质含量为I00~ 150 g·kg-1,少部分区域为150 ~318.4 g· kg-1.  相似文献   

10.
川中丘陵县域土壤碳氮比空间变异特征及其影响因素   总被引:18,自引:0,他引:18  
以四川仁寿县为案例区,通过实地采样分析了该紫色丘陵区县域尺度上土壤碳氮比的空间变异特征及其影响因素.结果表明:研究区表层土壤碳氮比(C/N)在4.84~21.79之间,平均值为11.93,变异系数26.3%,属中等程度的空间变异.半方差分析表明,土壤C/N的块金效应为73.0%,其空间分布受结构性因素和随机因素的共同影响,但受随机性因素的影响更大;土壤C/N的空间分布特征表现为西北和东南高、中部低的趋势,大部分区域土壤C/N处于10.0~13.5之间.成土母质、土壤类型、地形和土地利用方式对土壤C/N的影响显著(P<0.05);地形因子中高程和坡度与土壤C/N呈显著正相关关系(P<0.05),成土母质可解释土壤C/N 8.7%的空间变异,土类、亚类和土属的解释能力分别为3.8%、5.0%、8.7%,地形因子的解释能力为0.8%;土地利用方式对土壤C/N空间变异影响程度最高,达到23.9%,是调控该区域土壤C/N的重要因素.  相似文献   

11.
喀斯特典型坡地旱季表层土壤水分时空变异性   总被引:13,自引:1,他引:12  
张川  张伟  陈洪松  聂云鹏  叶莹莹  王克林 《生态学报》2015,35(19):6326-6334
基于网格(10 m×10 m)取样,用地统计学方法研究了桂西北喀斯特地区典型灌丛与草灌两种植被类型坡地(90 m×120 m)旱季(2011年10月至2012年3月)表层(0—16 cm)土壤水分含量的空间变异特征。结果表明:整个采样期灌丛坡地的土壤水分含量明显要高于草灌坡地,两种类型坡地的表层土壤水分含量均属于中等程度的变异(10%Cv100%),且灌丛坡地的变异系数大于草灌坡地。两种植被类型坡地的土壤水分含量与降雨量的波动变化趋势相同,而与土壤水分变异系数的变化趋势整体相反。土壤水分含量均具有明显的空间依赖性和空间结构。两种类型坡地土壤水分的变程与块基比的变化趋势都大致相反,灌丛坡地土壤水分的变程与土壤水分含量均值的变化趋势在采样前期和中期趋势相反,在采样后期趋势相同,而草灌坡地土壤水分的变程与土壤水分含量均值的变化趋势大致相同。两块样地土壤水分的变异系数、变程与块基比均随土壤水分含量的变化有一定的季节变化规律,说明平均土壤水分含量对土壤水分空间格局的主导作用是持续存在的,结合研究目标可以有效指导后续的土壤采样。虽然两块样地表层土壤水分含量整体沿坡面自上而下呈递增趋势,但土壤水分含量最大值均分布在样地下坡位右侧地段,这主要与该地段坡度较缓、土壤厚度较大且碎石含量较低有关。  相似文献   

12.
The Gonghe Basin region of the Tibet Plateau is severely affected by desertification. Compared with other desertified land, the main features of this region is windy, cold and short growing season, resulting in relatively difficult for vegetation restoration. In this harsh environment, identification the spatial distribution of soil nutrients and analysis its impact factors after vegetation establishment will be helpful for understanding the ecological relationship between soil and environment. Therefore, in this study, the 12-year-old C. intermedia plantation on sand dunes was selected as the experimental site. Soil samples were collected under and between shrubs on the windward slopes, dune tops and leeward slopes with different soil depth. Then analyzed soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the spatial heterogeneity of soil nutrients was existed in C. intermedia plantation on sand dunes. (1) Depth was the most important impact factor, soil nutrients were decreased with greater soil depth. One of the possible reasons is that windblown fine materials and litters were accumulated on surface soil, when they were decomposed, more nutrients were aggregated on surface soil. (2) Topography also affected the distribution of soil nutrients, more soil nutrients distributed on windward slopes. The herbaceous coverage were higher and C. intermedia ground diameter were larger on windward slopes, both of them probably related to the high soil nutrients level for windward slopes. (3) Soil “fertile islands” were formed, and the “fertile islands” were more marked on lower soil nutrients level topography positions, while it decreased towards higher soil nutrients level topography positions. The enrichment ratio (E) for TN and AN were higher than other nutrients, most likely because C. intermedia is a leguminous shrub.  相似文献   

13.
以贵州喀斯特地区两种主要土壤类型(石灰土和黄壤)为研究对象,通过测定土壤pH值、土壤有机碳(SOC)含量和植物优势种、枯枝落叶、土壤有机质的稳定同位素(δ13Csoc值)组成,探讨了该地区石灰土和黄壤剖面SOC垂直分布特征和δ13Csoc值组成差异。结果表明,与黄壤相比,石灰土剖面的SOC含量较高,石灰土剖面和黄壤剖面SOC含量变化范围分别在3.6~69.8和2.4~51.2g·kg-1。黄壤和黄色石灰土剖面SOC主要集中在0~20cm深度内,而黑色石灰土剖面从0~60cm逐步减少。黑色石灰土和黄壤剖面δ13Csoc值变化范围分别在-22.9‰~-21.5‰和-25.6‰~-22.4‰,前者较后者变化小。从剖面表土向下,黄壤剖面δ13Csoc值均出现逐步增加的趋势,而石灰土剖面δ13Csoc值从剖面表土向下出现上升-降低-不变的变化趋势。黄色石灰土剖面δ13Csoc值变幅较大,变化范围为-23.7‰~-18.2‰。在枯枝落叶转化为表层土壤有机质的过程中,石灰土剖面δ13Csoc值变幅高于黄壤。其中,黄壤剖面δ13Csoc值升高了2.6‰~3.0‰,石灰土剖面δ13Csoc值升高了5.5‰~6.3‰。上述结果揭示了SOC含量及其δ13C值随深度变化的差异,反映植物残体的输入及其在土壤中分解累积特征,有助于揭示SOC循环过程及规律和了解剖面土壤成土过程。  相似文献   

14.

This study examines the relations between the local variations in vegetation and topography using logistic regression (LR) and GIS in a snowy basin in the Ohu Mountains of northeastern Japan. The spatial distribution of seven vegetation classes interpreted from aerial photographs—(a) large-sparse crown beech forest, (b) middle-dense crown beech forest, (c) dwarf beech scrub, (d) dwarf bamboo thicket, (e) Japanese white pine forest, (f) snow-avalanche scrub or meadow, and (g) riparian forest—was analyzed with terrain parameters derived from a 10 m digital elevation model (10 m DEM) and parameters of landslide distribution and surface geology. While large-sparse crown beech forests dominate the slopes, smaller crown beech forests or scrubs are often found on the west-facing (i.e., windward side) upper parts of slopes and crests. On the contrary, snow-avalanche scrubs or meadows are found on the leeward side of steep slopes and concave plan curvatures. Dwarf bamboo thickets are often found on east-facing (i.e., leeward side) gently sloping crests, where the snow remains until summer. Japanese white pine forests respond positively to sharp ridges, whereas riparian forests show a positive response to the gently sloping lower parts of slopes and bottomlands at low elevation. The heterogeneous vegetation distribution in the basin indicates differences in site conditions (e.g., soil–water conditions), and the existence of various disturbance regimes induced by the strong winter monsoon with heavy snowfall, snow movements (e.g., avalanches), and temporal differences in snowmelt on different topographies. The estimated vegetation maps could be used for forest management and restoration.

  相似文献   

15.
Herrera  Bernal  Finegan  Bryan 《Plant and Soil》1997,191(2):259-267
A 28 yr old secondary lowland rain forest in Costa Rica was dominated by two tree species of contrasting ecologies, Vochysia ferruginea - a species typical of well-drained but infertile soils of high Al saturation, and Cordia alliodora, a species requiring soils of at least moderate fertility. The two species exhibited markedly different spatial distributions in the forest and we sought to determine whether or not these different distributions were related to variation in substrate conditions and the nutrient requirements of the two species. Two soil types were present: Ultisols (Typic Haplohumults) and Inceptisols (Typic Dystropepts) and topography was of low hills. The study formed part of an analysis of site quality for timber production in the two species and therefore used standard forestry methods for such analyses. 36 plots of 20 m×20 m were established using predetermined criteria of site uniformity, presence of at least four dominant trees of at least one of the study species, and absence of disturbance. The abundance (number of individuals 10 cm dbh) of each species was determined in each plot. Soil samples were taken in 27 of the 36 plots, 9 plots being considered to replicate conditions already sampled, and 14 soil chemical and physical variables were measured using standard methods. Foliar nutrient analyses were carried out for trees of both species with crowns fully exposed to sunlight, distributed across the gradient of soil conditions. Variations in species abundances were not related to soil type, but plots in which Vochysia ferruginea was more abundant tended to be on steeper slopes with soils of higher exchangeable acidity and lower concentrations of Mn; Cordia alliodora was more abundant on gentler topography where soils had much lower exchangeable acidity but higher Mn. Differences between the two species in foliar nutrient concentrations were marked and supported previous interpretations of their nutrient requirements; foliar nutrients of Vochysia ferruginea were typical of tree species of moist tropical forest on infertile soils, and those of Cordia alliodora typical of a species requiring more fertile soils. Factors such as the distributions of seed trees at site abandonment may affect the spatial distributions of tree species in secondary forests such as that studied. The relationships of the distributions of the two species to substrate variation, however, and their evidently different nutrient requirements, support the hypothesis that variation in the composition and structure of the forest studied is at least partially related to exchangeable acidity and its dominant cation, Al.  相似文献   

16.
水蚀风蚀交错区退耕坡面植被利用对产流产沙的影响   总被引:1,自引:0,他引:1  
为有效利用水蚀风蚀交错区退耕封育坡面植被,确定合理的植被利用强度非常必要.本试验选取黄土高原水蚀风蚀交错区典型小流域——六道沟小流域为试验区,在多年退耕封育坡面布设径流小区,通过人工模拟降雨试验,研究植被地上部分在不同利用强度下各坡度(10°、20°和30°)坡面产流、产沙变化特征,以确定合理的利用强度. 结果表明: 次降雨过程中径流速率大体可分为两个阶段:初期迅速增长阶段和中后期增长变缓或趋于准稳定阶段.侵蚀速率的变化趋势因坡度的不同而略有差异.利用强度对产流量有显著影响,产流量随利用强度的加强而增加.坡度对侵蚀量影响显著,侵蚀量表现为20°坡面>30°坡面>10°坡面.以植被地上部分未利用小区为对照,相对增水量和相对增沙量均随利用强度加强而增加.结合降雨资料推测,退耕15年左右坡面植被地上部分盖度达到25%时,坡面年土壤侵蚀量基本低于容许土壤流失量.应重视该区20°坡面植被的恢复治理工作.  相似文献   

17.
在桂西北喀斯特洼地,用地统计学方法研究了旱季初期湿润和干旱条件下表层(0~5和5~10 cm)土壤水分的空间结构及其分布特征.结果表明,表层土壤水分存在明显的空间异质性和各向异性,呈现差异显著的斑块状分布格局.湿润条件下,土壤水分具有中等和较强的空间相关性,变程分别为33.15 m和15.75 m,其中0~5 cm层具有明显的趋势效应;干旱条件下,土壤水分则呈现出强烈的空间相关性,而且相似斑块的空间尺度有所减小,变程最小仅为8.22m;在平均含水量较低时(干旱条件)其变异程度较大,实际应用中应根据平均含水量水平采取不同的取样设计.实验区表层土壤水分空间变异及其分布格局的显著差异,主要是受地貌、平均含水量(降水)和地形等因素的影响.  相似文献   

18.
Iberian gypsophile plant communities are considered a priority for conservation by the European Community because of their highly specialized flora in gypsum outcrops in arid and semiarid regions. Despite the ecological importance of these ecosystems, the edaphic factors that constrain plant communities on gypsiferous soils remain unclear. It has been proposed that both the chemical and physical restrictive conditions of gypsum soils determine gypsophily in plants. Here we hypothesize that the rigors of the gypsum soil environment depends on topography, decreasing from flat areas on hilltops to south-oriented slopes and finally to slopes oriented to the north. We also hypothesized that the relaxation of the rigors of the gypsum soil environment with topography affects both to individual plant and community characteristics of gypsophile vegetation: we expect a reduction of gypsophyte abundance, an increase of diversity and the amelioration of facilitative interactions of plant species. We analysed the physical and chemical properties of gypsum soils that have been proposed that determine the rigors of the gypsum soil environment (i.e.: unbalanced ion concentrations and superficial soil crust). The predicted rigor gradient along topographical locations was confirmed and was mainly caused by superficial soil crust. The decreasing rigor gradient was accompanied by a fall in the abundance of gypsophytes. However, when gypsophytes were considered separately, several patterns were observed, indicating distinct tolerance to relaxation of rigor of the gypsum soil conditions and different competition abilities between gypsophytes. Plant species were more clumped, and gypsophile communities presented higher diversity, evenness and richness values where rigor of gypsum soil conditions were maximum (flat hilltop positions). Relaxation of rigor (north-oriented slopes) was characterized by loss of facilitative interaction between species and the dominance of the gypsovag Rosmarinus officinalis L., although richness was still very high, which can be attributed to the coexistence of gypsophytes and gypsovags. We conclude that the rigor of gypsum soil environment gradient with topography is mainly determined by superficial soil crust, and it is a crucial determinant of gypsophile plant communities.  相似文献   

19.
在桂西北喀斯特洼地,用地统计学方法研究了旱季初期湿润和干旱条件下表层(0—5和5~10cm)土壤水分的空间结构及其分布特征.结果表明,表层土壤水分存在明显的空间异质性和各向异性,呈现差异显著的斑块状分布格局.湿润条件下,土壤水分具有中等和较强的空间相关性,变程分别为33.15n,和15.75m,其中0~5cm层具有明显的趋势效应;干旱条件下,土壤水分则呈现出强烈的空间相关性,而且相似斑块的空间尺度有所减小,变程最小仅为8.22m;在平均含水量较低时(干旱条件)其变异程度较大,实际应用中应根据平均含水量水平采取不同的取样设计.实验区表层土壤水分空间变异及其分布格局的显著差异,主要是受地貌、平均含水量(降水)和地形等因素的影响.  相似文献   

20.
Aims Understanding relationships between vegetation and environments is of importance for ecosystem restoration and management. However, information on how environments influence the floristic patterns of shrublands is lack, especially in the subtropical China. In this study, we explored how environments regulate species composition of shrublands at landscape scale in mid-subtropical China.Methods We investigated species composition and measured the climate and soil environments for 207 shrubland plots in mid-subtropical China (24°39′–30°08′N, 108°47′–114°15′E). We applied a hierarchical cluster analysis and indicator species analysis based on the Bray–Curtis similarity index to identify the main shrubland types and employed principal coordinate analysis (PCoA) to explore the relationship between floristic composition and environment.Important findings We identified four shrubland types occurring in different environmental conditions. Montane shrubland, dominated by species suitable for cool climates (e.g. Rhododendron simsii), were distributed in steep areas at comparatively high altitudes; foothill shrubland, dominated by mesophilous species (e.g. Loropetalum chinense), were distributed in low mountains and hills; pioneer shrubland, dominated by fast grow and short-life cycles species (e.g. Rhus chinensis), were distributed at low altitudes with dense population; and finally, limestone shrubland, dominated by calcicole plants (e.g. Coriaria nepalensis), were distributed in the extensive karst areas. Communities occurring in high pH soils were completely separated from those in low pH soils according to the hierarchical cluster analysis. PCoA ordination associated the four types with distinct edaphic and climatic gradients. Soil pH explained 63.3% of variation in PCoA, followed by soil depth and soil bulk density.  相似文献   

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