半干旱黄土区沟间天然草地植被空间分异特征

选取陕北黄土高原半干旱丘陵沟壑区梁峁坡作为研究区,以40 m为间隔,调查了31个草本样方,采用传统统计方法和地统计学方法分析了天然草地植被空间分异特征.线性相关和秩相关分析表明:坡位是影响草本植物盖度及干鲜比的重要因子,坡向是影响草本植物平均高度和生物量的重要因子,坡度对草本植物空间分布没有显著影响.使用莫兰指数(Moran氏Ⅰ指数)进行空间相关分析表明:草本植物盖度、高度和干鲜比在60 m间隔距离内呈空间正相关,生物量在180 m内存在显著空间相关性.半方差分析表明,球状理论变异函数模型能够很好地模拟草本植物高度和生物量的空间变异,其变程分别为99.3和66.6 m,且均具有强烈的空间自相关性.干鲜比的理论变异函数模型为高斯模型,变程为78.4 m,具有强烈的空间自相关性;盖度的理论变异函数模型为线性模型.     

长白山阔叶红松林表层土壤水分空间异质性的地统计学分析

采用时域反射仪对长白山原始阔叶红松林3块50m×50m样地表层土壤(0～7.5cm)水分进行测定,应用地统计学的理论与方法对表层土壤水分的空间异质性进行分析.结果表明:研究区3块样地表层土壤水分变异系数分别为24.32%(样地1)、24.11%(样地2)和23.60%(样地3),均属于中等变异性;该区表层土壤水分的理论变异模型为球状模型,具有高度的空间异质性,其空间异质性以空间自相关部分为主;表层土壤水分的结构比分别为57.9%(样地1,属中等相关性)、83.3%和90.0%(样地2和3,属强烈的空间相关性);研究区表层土壤水分的变程在5.5～13.1m,与贝叶斯方法估计的变程相差不大;通过克立格插值估计,研究区表层土壤水分含量的平均值分别为49.3%(样地1)、52.8%(样地2)和42.6%(样地3).     

红火蚁入侵对荔枝园土壤性理化质的影响

对红火蚁Solenopsis invicta Buren荔枝园发生区土壤理化性质进行了研究,结果表明:3类红火蚁不同发生区之间、红火蚁蚁巢4个不同方位之间以及距红火蚁蚁巢中心不同距离之间的土壤各项理化性质均有显著的差异(p＜0.01).从对照区、轻度发生区到重度发生区土壤粘粒变得越来越细,酸性逐渐升高.土壤有机质、碱解N、有效P的含量在轻、重度发生区较对照区分别下降了29.0%与39.9%、42.1%与53.6%、43.3%与52.6%,但速效K的含量在轻、重度发生区较对照区则分别升高了8.5%与34.0%.此外,在红火蚁发生区,蚁巢上的土壤理化性质与蚁巢以外的土壤理化性质明显不同(p＜0.01).蚁巢上的土壤明显比蚁巢以外的土壤酸性强.土壤有机质、碱解N、有效P的含量在蚁巢上明显最小,但土壤速效K的含量在蚁巢上明显最高.蚁巢不同方位上土壤的理化性质相对差异较小,红火蚁在荔枝园的分布存在一定的空间随机性.     

福建省入侵红火蚁扩散规律研究

【目的】重大入侵害虫红火蚁Solenopsis invicta Buren广泛分布传播于世界各地,为了掌握红火蚁在新入侵地的传播和扩散的规律,对红火蚁入侵史进行溯源,以期为预防红火蚁入侵提供重要依据。【方法】本文对福建省各地入侵红火蚁的基本入侵参数进行分析,分别对入侵时间与蚁巢数量、蚁巢发生密度以及不同生境蚁巢密度进行模型拟合。【结果】结果表明,入侵方式和入侵地生境的差异导致了入侵红火蚁不同种群的发展状态。由废旧资源携带传入的入侵红火蚁种群,其发生面积较小,扩散的速率较慢,为28.1~116.4 m/年;由草皮苗木携带传入的入侵红火蚁种群,其发生面积较大,扩散的速率较快,为126.1~555.5 m/年。【结论】建立了蚁巢数量、密度与入侵时间之间的关系模型,分别为N=1 003.9Ln(t)+336.27,D=0.0966e~(0.583t),并以此推测三个入侵事件的发生时间范围。     

长白山阔叶红松林表层土壤木本植物细根生物量及其空间分布

2008年在长白山北坡原始阔叶红松林内选择3块50m×50m样地,采用地统计学方法对表层土壤中木本植物细根生物量及其分布特征进行了定量研究.结果表明:3块样地0～20cm土层中木本植物活细根生物量分别为3.195、1.930和2.058t·hm-2,死细根生物量分别为0.971、0.581和0.790t·hm-2,0～10cm土层中,死、活细根生物量之间无显著相关关系,而10～20cm土层中,二者呈显著正相关关系(r=0.352,P0.05),死、活细根生物量的实际变异函数大多符合球状理论模型.空间自相关引起的空间异质性占总空间异质性的百分比平均大于70%,各样地活、死细根生物量变程分别为5.2、14.6、9.8m和4.3、20.4、20.1m.采用贝叶斯统计方法对3块样地活细根生物量空间自相关范围进行估计的结果与地统计学方法的统计结果一致.     

杨树光肩星天牛种群空间格局的地统计学研究

根据在宁夏青铜峡市４块不同类型样地上收集到的光肩星天牛卵、幼虫和成虫的数量和位置资料,应用地统计学方法对其处群的空间格局进行了研究,结果表明,在各种林型中天牛卵和幼虫的数量具有明显的空间依赖性,其变程分别为２０－４０ｍ和２８－１７０ｍ,局部空间连续性强度分别为０．２６－０．４７和０．１４－０．５５５;而成虫的数量没有表现出空间依赖性,在空间呈随机分布。对不同样方大小的变异曲线图进行比较得知;在一定     

喀斯特典型坡地旱季表层土壤水分时空变异性

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。     

基于GIS的缓坡烟田土壤养分空间变异研究

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.     

黄土高原小流域土壤养分的空间异质性

利用地理信息系统的空间分析功能,通过地统计学的半变异函数定量研究了黄土高原典型小流域土壤养分的空间异质性特征。结果表明;土壤有机质,全氮,有效氮,全磷和有效磷的理论模型均为球状模型,由随机因素引起的空间变异占空间总变异的比例小,其值分别为13.333%,10.938%,22.000%,9.091%和27.536%,反映5种养分具有较强的空间自相关格局,但它们的空间自相关范围具有明显的差异。土壤全氮和有效氮变程小,分别是90m和110m,有机质次之,变程是120m,而土壤全磷和有效磷的变程最大为160m,研究成果将有效地指导土壤的取样设计,以及进行土壤养分的空间内插和制图。     

喀斯特常绿落叶阔叶混交林植被的空间异质性

基于广西环江木论国家级自然保护区喀斯特典型峰丛洼地常绿落叶阔叶混交林2 hm2动态监测样地,选择4个多样性和5个群落结构属性变量,运用地统计学和分形几何学理论方法,分析植被的空间异质性、分形特征和分布格局,以探讨其维持机制。结果表明:(1)样地树木种类和除平均高度外的4个结构属性变量均值适中,变异系数较高(48.37%～71.01%),植物多样性丰富且稳定性强,Shannon指数、Simpson指数和均匀度指数变异系数仅在5.49%～22.64%之间。(2)除均匀度的Moran’s I系数接近0且无规律外,其他8个属性变量均有不同程度的空间自相关性,分别用球状、指数和高斯模型拟合的决定系数(R2)高达0.900～0.982,C/(C0+C)值和分维数D值分别在0.582～0.827和1.738～1.871之间,具有中等以上的空间依赖性。(3)密度、平均冠幅和高度的自相关范围和变程小于其他指标,其分布和形成过程决定了整个森林植被的空间格局。(4)森林植被的Kriging等值线图充分表征了人为干扰、地形、土壤质量的综合差异。(5)自相关、半方差模型的变程和Kriging等值线图综合分析表明,喀斯特峰丛洼地常绿落叶阔叶混交林空间异质性研究的采样间隔10 m左右较适宜,但采样范围应大于10hm2,这对确定该区域动态监测样地的面积具有一定的指导意义。     

基于大样地油松种群的地统计学分析

在对山西省灵空山国家级自然保护区4 hm2样地内油松种群调查的基础上,采用地统计学的半方差分析法对油松种群的空间分布格局进行了研究,并用克里金插值法绘制了不同径级油松种群胸径的等值线图。结果表明:油松种群径级Ⅰ、Ⅲ、Ⅳ的最优半方差拟合模型均为指数模型,径级Ⅱ的最优拟合模型为球状模型,说明4个径级都为聚集分布且均为中等的空间相关性;油松种群径级Ⅰ、Ⅱ、Ⅲ、Ⅳ的空间自相关范围分别为23.4、15.2、11.1、24.9 m,分维数大小依次为径级Ⅱ(1.999)径级Ⅲ(1.995)径级Ⅳ(1.973)径级Ⅰ(1.969)。以树高为变量作半方差分析的结果与以胸径作为变量的分析结果基本一致,且以树高为变量进行的类似分析也进一步证实了该结果的准确性。利用Surfer软件绘制的Kriging图直观反映了油松种群空间分布的斑块聚集效果,即油松种群空间格局纹理图。本文利用地统计学的半方差分析法和Kriging插值方法相结合弥补了传统格局分析方法的不足,能精确直观地反映出油松种群个体的空间分布、斑块的聚集效果等,可为植物空间分布格局的分析提供有效的研究方法。     

Multi-scale pattern analysis of a mound-building termite species

Termite mounds are a widespread feature in most African savannas. These structures exhibit high nutrient contents and often host a special vegetation composition. In this study, we analysed mound distribution patterns of a fungus-growing termite species, Macrotermes michaelseni, an important ecosystem engineer in the savannas of Namibia. Inhabited mounds taller than 0.7 m were regularly distributed. We view this pattern as a result of intraspecific competition. The heights of mounds taller than 0.7 m were correlated positively with their distance, such that mounds closer together, i.e. up to inter-mound distances of approximately 50 m, tended to be smaller than average. This indicates that intraspecific competition for foraging areas controls mound distribution pattern and colony size. Differences between mound heights increased on the spatial scale up to inter-mound distances of 80 m. We assume that the foundation of new colonies is only possible in unoccupied patches. In such patches, young colonies are able to occur close together as they have a relatively low foraging demand and therefore a low spatial demand. In contrast, their critical distance to taller colonies with higher foraging demands is rather large, which leads to the observed increasing difference of mound heights with increasing distances between them.     

芦芽山亚高山草甸、云杉林土壤有机碳、全氮含量的小尺度空间异质性

分析比较了山西芦芽山不同海拔处分布的亚高山草甸（样地A,海拔2756.3 m;样地B,海拔2542.3 m）和云杉林（样地C,海拔2656.8 m;样地D,海拔2387.2 m）土壤有机碳和全氮的小尺度空间异质性特征。结果表明：相同植被类型下海拔较高的样地有机碳含量较高（A：49.84 g/kg,B：38.33 g/kg,C：47.06 g/kg,D：40.67 g/kg）,而较低海拔的样地土壤有机碳含量的异质性较高;除样地A以外的其他3个样地均表现为高度空间依赖性。亚高山草甸土壤全氮含量的异质性远远高于云杉纯林,四个样地中均表现出强的空间自相关性。亚高山草甸样地土壤有机碳和全氮含量均在较大尺度上空间自相关,云杉纯林样地则表现为较小尺度的空间自相关变异。     

Foraging behaviour of the root vole Microtus oeconomus in fragmented habitats

The effect of habitat fragmentation on spatial foraging behaviour in the root vole Microtus oeconomus was investigated in seven experimental populations. Four of the populations were established in large, continuous blocks (30 × 95 m) of meadow habitat (treatment plots), whereas the three remaining populations had six small rectangular habitat fragments (30 × 7.5 m) with variable inter-fragment distances (control plots). Both the small habitat fragments and the large continuous habitat were embedded in a non-habitat matrix area which was regularly mowed. Half-way through the study period, the continuous habitat in treatment plots was destroyed by mowing to give a configuration identical to the control plots. Dyed bait placed at the edges and in the interior of habitat fragments as well as in the matrix area was used to reveal differential use of these areas for foraging. Animals in the small-fragment plots fed more than expected along the edges, while edges were used according to availability in the large blocks of continuous habitat. In the fragmented plots, the frequency of foraging in the matrix decreased with increasing distance to the fragment border and with increasing inter-fragment distances. Furthermore, the frequency of use of more than one habitat fragment in individual foraging ranges decreased with increasing inter-fragment distances. Reproductively inactive animals of both sexes fed more often along habitat edges than reproductively active animals. Reproductively active females fed exclusively in one habitat fragment, whereas inactive animals and especially reproductively active males frequently included more than one fragment in their foraging ranges. The only effect of habitat destruction was less foraging in the matrix habitat in the post-destruction treatment plots compared to the permanently fragmented control plots. This was probably an effect of different matrix quality. Root voles in these experimental populations forage in edge and matrix habitat with great risk of becoming victims to predation, and the results are interpreted in this context. Received: 19 August 1998 / Accepted: 30 June 1999     

Characterization of the spatial dispersion of corn root injury by corn rootworms (Coleoptera: Chrysomelidae)

The dispersion of root injury to Zea mays L. by corn rootworm, Diabrotica spp., larvae was characterized using geostatistics to determine the appropriate sampling distance to obtain independent estimates of root injury. We also investigated the effect of the root injury levels on the spatial dependence of root injury at three different spatial scales: large-scale study with 25-m sampling distance in three, 8-ha fields; moderate-scale study with 0.2-m sampling distance in six, 2-ha fields; and small-scale study with exhaustive sampling in eight, 12-m(2) plots within cornfields. In the large-scale study, a nugget model best fit the semivariograms, indicating the dispersion of root injury exhibited a random pattern. In the moderate-scale study, all the semivariograms were best fit with an exponential model, and 68 to 96% of the variability was explained by spatial dependence, suggesting a high degree of spatial aggregation of corn root larval injury. The ranges of semivariograms fell within < 4 m, except one field that had the range of 14.7 m. In the small-scale study, the Gaussian, exponential, or spherical models fit the semivariograms best and 50 to 89% of the variability was explained by spatial dependence, suggesting spatial aggregation of root injury. The ranges of semivariograms were from 0.35 to 1.04 m. In the small-scale study, the degree of spatial dependence increased significantly (P < 0.05) as the average root injury increased within the range of root injury observed in the study. These results suggest that the minimum distance between root samples in small-plot insecticide trials should be > 1 m within a row to obtain unbiased estimates of root injury.     

南大港湿地飞蝗种群分布与芦苇空间格局的关系

利用地统计学方法,在GIS平台下研究南大港湿地东亚飞蝗Locusta migratoria manilensis(Meyen)和芦苇(Phragmites australis)种群的空间格局及两者间的关系。结果表明,研究区域内飞蝗、芦苇种群均具有较强的空间相关性,变异函数曲线都为球状模型,空间自相关范围分别为502m和814m。其次,飞蝗主要集中分布在研究区域内芦苇长势较差(30~70棵.m-2)的东北部和东南部地块,而在长势较好的西部(>120棵.m-2)、南部(70~120棵.m-2)和极差的北部(<30棵.m-2)几乎没有蝗虫的分布,且蝗虫种群数量与芦苇密度存在显著的相关性。     

Effects of spatial heterogeneity on butterfly species richness in Rocky Mountain National Park, CO, USA

We investigated butterfly responses to plot-level characteristics (plant species richness, vegetation height, and range in NDVI [normalized difference vegetation index]) and spatial heterogeneity in topography and landscape patterns (composition and configuration) at multiple spatial scales. Stratified random sampling was used to collect data on butterfly species richness from seventy-six 20 × 50 m plots. The plant species richness and average vegetation height data were collected from 76 modified-Whittaker plots overlaid on 76 butterfly plots. Spatial heterogeneity around sample plots was quantified by measuring topographic variables and landscape metrics at eight spatial extents (radii of 300, 600 to 2,400 m). The number of butterfly species recorded was strongly positively correlated with plant species richness, proportion of shrubland and mean patch size of shrubland. Patterns in butterfly species richness were negatively correlated with other variables including mean patch size, average vegetation height, elevation, and range in NDVI. The best predictive model selected using Akaike’s Information Criterion corrected for small sample size (AIC_c), explained 62% of the variation in butterfly species richness at the 2,100 m spatial extent. Average vegetation height and mean patch size were among the best predictors of butterfly species richness. The models that included plot-level information and topographic variables explained relatively less variation in butterfly species richness, and were improved significantly after including landscape metrics. Our results suggest that spatial heterogeneity greatly influences patterns in butterfly species richness, and that it should be explicitly considered in conservation and management actions.     

Spacing patterns of an Acacia tree in the Kalahari over a 61-year period: How clumped becomes regular and vice versa

Nearest tree neighbour distances and the tree spatial formation on a large scale over time and space replicates were examined. The study was conducted in a natural savanna ecosystem in the Southern Kalahari, South Africa. Nearest tree neighbour and point pattern analysis methods were used to investigate changes in the spatial pattern of trees in two plots. Trees larger than 2 m canopy diameter were mapped. We used aerial photographs of the study area from 1940, 1964, 1984, 1993, and a satellite image from 2001 to follow two plots over time. Field work was carried out too for classification accuracy. We were able to identify and individually follow over 2400 individual trees from 1940 until 2001. Nearest neighbour analysis results indicate that dead trees were on average closer to their nearest neighbouring trees than living trees were to their neighbours. Most dead trees were on average 6 m from their nearest neighbours, while most living trees were about 20 m apart. Point pattern analysis results show a cyclical transition from clumped to random and sequentially to regular tree spacing. These transitions were not correlated across two plots. Generally, decreases in small-scale clumping coincided with periods of high mortality. Our findings show that regular, clumped, and random tree pattern can occur, pending on time, location, and scale within the location.     

云冷杉针阔混交林叶面积指数的空间异质性

叶面积指数(Leaf area index,LAI)是森林生态过程的关键参数和描述森林冠层结构的重要指标。用半球摄影技术对吉林省汪清林业局金沟岭林场的10块1 hm2云冷杉针阔混交林的LAI进行测定,采用地统计学的半变异函数和普通克里格法对研究区的LAI的空间异质性进行了分析。结果表明:10块样地的10 m×10 m小样方内以及样地间的LAI离散程度较小,但分布有一定的规律。LAI的空间相关性存在不确定性,可由线性、孔状、高斯3种模型有效的描述,空间相关性存在的尺度范围变异大,中等和强空间相关性的影响范围在15—155m之间,10块样地LAI的空间相关性的影响范围平均为65.637m。普通克里格插值结果显示,LAI的空间分布呈明显的条带状和斑块状的梯度变化。LAI与林分平均胸径、林分平均高和林分平均冠长呈显著负相关,与林分平均冠幅、林分密度以及树种个数呈显著正相关。研究结果可为不同尺度云冷杉针阔混交林LAI的估计提供依据。