西鄂尔多斯狭叶锦鸡儿种群分布格局

在内蒙古高原西鄂尔多斯选不同盖度的狭叶锦鸡儿样地进行实地调查,根据植株体积划分龄级,运用点格局分析法对狭叶锦鸡儿种群分布格局及龄级之间的空间关联性进行研究。结果表明:狭叶锦鸡儿空间分布格局和空间关联性与空间尺度、植株发育程度及环境异质性有密切联系,在小尺度下趋向于随机分布,随尺度增大呈聚集分布;低盖度种群为典型的增长型种群,随着盖度的增加成长为稳定型种群;随植株龄级逐步增大,种群分布类型由聚集分布向随机分布转化;种群龄级相差越大,空间正关联性越弱。     

白喉乌头种群空间分布格局初步研究

采用聚类分析方法和邻接格子样方法对那拉提草原毒害草白喉乌头(Aconitum leucostomum)种群格局进行研究,以期探明其种群空间分布格局类型和分布规律,了解种群群落内部结构形成机制及群落分布成因。结果表明:白喉乌头在群落中的优势度在2.174~3.6和6.62~6.983范围内,呈现均匀分布,平均密度为0.58株·m^-2;不同样方面积下呈现均匀分布,不同尺度下表现出一定的差异性,样方面积在4 m²和32 m²时,白喉乌头格局规模最大;白喉乌头密度与样方面积呈极显著的线性关系。白喉乌头的分布格局在较小尺度上格局规模基本上比较稳定,空间点格局在各尺度上呈现均匀分布,但不同地点还是表现出尺度上的差异。     

高寒草地不同坡向金露梅种群空间分布格局研究

采用Ripley的k（d）函数分析方法及群落学调查法,对祁连山高寒草地不同坡向金露梅（Potentilla fruticosa）种群的空间格局分布特征进行了研究。结果表明,金露梅种群高度、密度和盖度阴坡〉平地〉阳坡,金露梅种群分枝数阳坡〉平地〉阴坡。金露梅种群的空间分布格局表现出与尺度密切相关的变化趋势,在阳坡,金露梅种群在较小尺度上表现为聚集分布,较大尺度上表现为随机分布;在阴坡,种群在所有尺度上表现为聚集分布,且聚集强度在降低;在平地,种群空间分布格局表现为均匀—随机的分布模式。坡向因素影响下的金露梅种群空间分布格局发生了较大转变,体现了植物种群的环境响应机制。     

高寒草地不同坡向金露梅种群空间分布格局研究

采用Ripley的k(d)函数分析方法及群落学调查法,对祁连山高寒草地不同坡向金露梅(Potentilla fruticosa)种群的空间格局分布特征进行了研究。结果表明,金露梅种群高度、密度和盖度阴坡平地阳坡,金露梅种群分枝数阳坡平地阴坡。金露梅种群的空间分布格局表现出与尺度密切相关的变化趋势,在阳坡,金露梅种群在较小尺度上表现为聚集分布,较大尺度上表现为随机分布;在阴坡,种群在所有尺度上表现为聚集分布,且聚集强度在降低;在平地,种群空间分布格局表现为均匀—随机的分布模式。坡向因素影响下的金露梅种群空间分布格局发生了较大转变,体现了植物种群的环境响应机制。     

高寒草甸矮嵩草群落10种植物的种群空间分布格局及其关系

运用两项局部样方方差(TTLQV)法和成对样方方差(PQV)法对高寒草甸矮嵩草群落中10种植物种群空问分布格局的类型、规模、强度和纹理进行了测定,根据不同区组规模/间隔上两物种间的相关系数r_(i,j),对分布格局的相互关系进行了分析。结果表明:所调查种群的分布格局都呈集聚分布;密度格局强度与环境格局强度在种间的变化基本一致;格局的强度与纹理之间并无直接关系;种群分布格局间的关系表明了种间发生相互作用的基本生境尺度。     

贵州喀斯特暖性草丛土壤物理因子空间异质性分析

土壤空间异质性是土壤的重要属性之一。采用地统计学中的半方差分析和分形分析研究了贵州喀斯特暖性草丛草地土壤物理因子的空间异质性。结果表明,土壤含水量、容重和孔隙度具有明显的空间异质性。在0~5 cm土层,空间异质性尺度为4~15 m;15~20 cm土层,空间异质性尺度为12~30 m;空间异质性程度随尺度变化,上层的土壤空间异质性小于下层。上层土壤孔隙度的空间异质性以空间自相关部分为主,占空间异质性的68.0%,而土壤含水量和容重随机部分的空间异质性相对较大;下层土壤物理性质的空间异质性全部是由空间自相关引起的。土壤含水量、容重和孔隙度的分维数都较大(大于或接近1.8),说明更小的尺度上生态学过程在各个变量要素空间格局的形成中起控制作用。     

西藏锦鸡儿群落表层土壤粒径空间分布特征及其与土壤水分相关性分析

通过比较西藏锦鸡儿沙堆内与沙堆间的土壤粒径组成特征,并应用统计学方法分析西藏锦鸡儿群落表层土壤粒径空间分布结构特征,及其与土壤水分的关系,为合理利用和保护西藏锦鸡儿资源提供依据。结果表明,沙堆内与沙堆间土壤粒径组成以细沙粒为主,占50%以上,粗沙粒和粗粉粒占9%~18%,且沙堆内与沙堆间石砾、粗沙粒和细沙粒含量差异显著(P0.05)。西藏锦鸡儿群落土壤细沙粒的空间异质性最大,空间自相关距离最小,各土壤粒级的空间自相关距离在0.86~1.85m。土壤水分与细沙粒呈显著正相关关系,与石砾和粗沙粒呈显著负相关关系。     

放牧率对内蒙古典型草原物种分布空间异质性的影响

本文应用统计学研究放牧率对内蒙古温带典型草原的羊草、大针茅、冷蒿和星毛委陵菜分布空间异质性的影响。结果表明:1)放牧率对典型草原物种空间分布有明显的影响。随着放牧率的增大,羊草与大针茅空间分布的随机性减小,空间自相关尺度逐渐增大。而在退化过程中入侵的冷蒿和星毛委陵菜,空间分布的随机性逐渐增大,空间自相关尺度亦呈增大趋势。在放牧率胁迫超过一定程度时,冷蒿空间分布的自相关开始下降,而星毛萎陵菜的空间分布则表现出强烈的随机性。2)格局图谱法反应出群落演替的主要矛盾,对于草原,格局图谱不受啃食和小尺度生境变化的影响,适用于不同放牧下群落之间的比较。     

河西走廊绿洲-荒漠过渡带湿生与盐生生态型芦苇种群空间分布格局分析

河西走廊绿洲-荒漠过渡带植被生长与健康状况对绿洲的稳定性起决定性作用.本研究选取有芦苇(Phragmites australis)天然分布的湿地和盐碱生境设置样地,调查湿生芦苇和盐生芦苇种群空间分布格局,采用6种聚集指标和Iwao模型,综合分析不同取样尺度及不同高度级芦苇种群的分布格局与聚集强度,为研究种群个体行为、种群扩散型提供一定信息.结果表明:湿生芦苇和盐生芦苇种群在取样面积为4、8、16、20、40和100 m2的6个尺度上均为集群分布,其中湿生芦苇聚集程度大于盐生芦苇,盐生芦苇有一定的随机分布趋势,表明湿生生境较盐碱生境更有利于增加芦苇种群聚集强度.湿生芦苇和盐生芦苇各自在不同取样尺度间聚集程度相当.湿生芦苇种群各高度级聚集程度均大于盐生芦苇,且尤以Ⅴ级和Ⅵ级湿生芦苇老龄阶段聚集强度最大.盐生芦苇Ⅱ、Ⅲ、Ⅳ、Ⅵ高度级有一定的随机趋势,但在Ⅰ、Ⅴ高度级无随机趋势.湿生生境水分不再是芦苇生长的限制因子,种群聚集度比较高;盐生生境由于水盐胁迫,土壤水分亏缺和较高的含盐量成为芦苇种群发展的限制因子,芦苇为了满足自身对水分、养分的需求,有随机分布的倾向,进而获得较大的空间及资源来维持其生存和发展.     

放牧强度对无芒隐子草小尺度空间分布特征的影响

为了研究荒漠草原无芒隐子草(Cleistogenes songorica)空间分布在不同放牧强度下不同尺度上的变化规律及其斑块特征,以内蒙古荒漠草原为研究对象,在对照区(CK)、轻度放牧(LG)、中度放牧(MG)和重度放牧(HG)条件下,选择2m×2m的代表性样方,记录无芒隐子草株丛的相对坐标,然后划分不同尺度并计算密度,再重新建立相对坐标并采用地统计分析方法进行分析,结果表明:荒漠草原无芒隐子草空间分布随着空间取样单元尺度的增加其缀块性减弱,CK区斑块主要在10cm×10cm尺度上,LG和HG区斑块主要呈现在20cm×20cm尺度上,而MG区在25cm×25cm尺度上的斑块性依然强烈;在LG和MG区,无芒隐子草空间分布比较复杂,空间异质性强烈;无芒隐子草空间分布主要受结构性因素主导,整体表现出随放牧强度增加异质性减弱的变化趋势。     

Grazing Intensity and Spatial Heterogeneity in Bare Soil in a Grazing-Resistant Grassland

We used very large scale aerial (VLSA) photography to quantify spatial patterns in bare soil in the northeastern Colorado shortgrass steppe. Using three pairs of pastures stocked at moderate (0.6 animal unit months [AUM] · ha^-1) versus very heavy (1.2 AUM · ha^-1) rates, we detected greater bare soil under very heavy (mean = 22.5%) versus moderate stocking (mean = 13.5%; P = 0.053) and a lower coefficient of variation across pastures under very heavy (0.48) versus moderate stocking (0.75; P = 0.032). Bare soil exhibited significant positive spatial autocorrelation across distances of 60–120 m under moderate stocking (Moran's I = 0.14), while patchiness at this scale was eliminated under very heavy grazing (I = -0.05). Across distances of 120–480 m, we observed no spatial autocorrelation with either stocking rate. Spatial autocorrelation was greatest at a separation distance of 2 m (I = 0.48–0.58) but was unaffected by stocking rate at this scale. Thus, very heavy grazing did not increase spatial autocorrelation in bare soil across scales of 2–480 m. Means and variability in the distribution of bare soil were not influenced by ecological site. Bare soil increased primarily at the scale of individual plant clusters through both increases in the density of small (2–20 cm) bare patch intercepts and increases in the frequency of bare patch intercepts of 20–60 cm (rather than &spilt; 20 cm). Our approach demonstrates the utility of VLSA for analyzing interactions between grazing and other landscape features and highlights the importance of spatially explicit sampling across broad scales (pastures) while testing for potential shifts in patchiness of bare soil at the scale of plant interspaces.     

Fluctuating fine-scale spatial genetic structure in the common shrews (Eulipotyphla,Mammalia)

The spatial genetic structure is a topical issue in the studies of various aspects of ecology and evolution. Using the multilocus autocorrelation method with hypervariable microsatellite genetic markers, we investigated a fine-scale pattern of genetic structure in 5 local populations of the common shrew Sorex araneus separated by distances of 300–1000 m (the Moscow chromosomal race). Spatial genetic autocorrelation analysis based on 5 microsatellite loci (expected heterozygosity >0.79) with 90 alleles revealed a consistent pattern of significant positive genetic structure. By testing the autocorrelation at multiple scales from 25 to 500 m, we found that positive spatial genetic structure is detectable in distance classes of <500 m. The weaker spatial genetic structure positively correlated with a higher ratio of nonresident individuals to residents’ activity (number of captures). In contrast to nonresident animals, the residents demonstrated prominent genetic structure. Genetic difference (F_ST) between the populations was significant (0.016–0.051) and comparable with that between populations of different races analyzed previously (0.016–0.038). F_ST was not associated with geographic distance. These demographic patterns allowed us to propose a scheme of genetic-structure dynamics involving periodic appearance of more related local groups and renewal of allelic profiles from а common pool where the alleles are mixed. The scheme predicts fluctuating genetic structure and random similar differences among local populations.     

科尔沁沙地退化草场土壤养分的空间结构分析

利用地统计学的方法对科尔沁沙地东南缘退化草场土壤养分的空间分析表明:该草场土壤有机质、全氮、全磷和速效钾都具有明显的空间结构特征,但结构异质性的程度和尺度表现各不相同,空间相关度依次为0.788,0.470,0.758和0.650,变程依次为7.8,18.4,5.9和6.5 m,分数维依次为1.857,1.881,1.933和1.920.Moran's Ⅰ系数在近距离(1～2 m)内均在0.4左右,随着距离增大,迅速减少,克立格制图进一步形象地直观描述该地退化草场土壤特性的空间结构特征.指出土壤全氮是该地区草地生态系统退化和恢复关注的重点.     

宁夏河东沙区防沙治沙区表层土壤有机质和土壤水分空间异质性

为探讨宁夏河东沙地沙漠化治理区表层土壤有机质含量和土壤含水量的空间分布规律,选取表层土壤作为研究对象,通过野外采样、室内试验以及地统计学数据分析,得出以下结果:研究区内有机质含量为0.5~3.48 g·kg^-1,均值为1.34 g·kg^-1,含量较低,Kriging 插值结果表明,有机质含量从北向南呈递减的态势,呈带状分布,空间变异较高,该研究区有机质含量最低是在西北地区,含量普遍在0.8~1.05 g·kg^-1,有机质含量高的地区位于研究区域南部,分布较少,此地有机质含量在2.20~2.36 g·kg^-1之间。土壤含水量较低,平均值为0.75%,Kriging 插值结果表明,该研究区表层土壤含水量的分布存在空间变异,由北向南递减。有机质含量和土壤含水量均表现出较高的空间自相关性,土壤有机质含量的空间相关范围相对较大,为36.69 m,土壤含水量的空间自相关距离较小,为8.48 m。     

基于无人机激光雷达与多光谱数据的不同放牧强度下草原冠层尺度特征研究北大核心CSCD

放牧活动不但影响草原生态过程,而且改变草原群落空间格局。为进行草地冠层连续变化的尺度对放牧强度响应的研究,基于无人机机载激光雷达和多光谱遥感获取亚米级的草原冠层数据,利用小波分析方法研究了不同放牧强度下草原冠层空间格局及其尺度特征,探究草原冠层高度(CH)、植被覆盖度(FVC)、归一化植被指数(NDVI)等不同冠层参数空间尺度特征对放牧强度的响应。结果表明:CH、FVC、NDVI的小波方差随放牧强度增大呈下降趋势,草原冠层空间结构整体趋于均匀;小波方差和系数实部分析显示,CH,FVC和NDVI的空间格局存在170~180 m、116~140 m等2个主特征尺度,不随放牧强度而变化,较为稳定;中度、重度放牧使植物群落在空间中产生了许多小斑块,植被盖度的空间格局在小尺度上的变化较大。     

Geographic Information System‐Based Analysis of the Spatial and Spatio‐Temporal Distribution of Zoonotic Cutaneous Leishmaniasis in Golestan Province,North‐East of Iran

Zoonotic cutaneous leishmaniasis (ZCL), a vector‐borne disease, poses serious psychological as well as social and economic burden to many rural areas of Iran. The main objectives of this study were to analyse yearly spatial distribution and the possible spatial and spatio‐temporal clusters of the disease to better understand spatio‐temporal epidemiological aspects of ZCL in rural areas of an endemic province, located in north‐east of Iran. Cross‐sectional survey was performed on 2983 recorded cases during the period of 2010–2012 at village level throughout the study area. Global clustering methods including the average nearest‐neighbour distance, Moran's I, general G indices and Ripley's K‐function were applied to investigate the annual spatial distribution of the existing point patterns. Presence of spatial and spatio‐temporal clusters was investigated using the spatial and space–time scan statistics. For each year, semivariogram analysis and all global clustering methods indicated meaningful persistent spatial autocorrelation and highly clustered distribution of ZCL, respectively. Eight significant spatial clusters, mainly located in north and northeast of the province, and one space–time cluster, observed in northern part of the province and during the period of September 2010–November 2010, were detected. Comparison of the location of ZCL clusters with environmental conditions of the study area showed that 97.8% of cases in clusters were located at low altitudes below 725 m above sea level with predominantly arid and semi‐arid climates and poor socio‐economic conditions. The identified clusters highlight high‐risk areas requiring special plans and resources for more close monitoring and control of the disease.     

不同管理措施对高寒草甸群落结构和披针叶黄华空间分布格局的影响

本研究以青藏高原高寒草甸的披针叶黄华（Thermopsis lanceolata）为研究对象，比较了放牧（GT）、围封（FT）和“围封+施肥+划破+补播”综合管理（CT）3种管理措施对披针叶黄华空间分布格局和植物群落结构的影响。结果表明，CT处理的披针叶黄华重要值低于FT和GT处理；CT处理的香农指数和均匀度指数显著高于FT和GT处理（P<0.05）；FT和CT处理的披针叶黄华株数显著少于GT处理（P<0.05）；在CT和FT处理中披针叶黄华空间分布格局表现为聚集分布（0~10 m尺度）；而GT处理中披针叶黄华种群表现为聚集分布（0~6.5 m尺度）、随机分布（6.5~7.5 m尺度）和均匀分布（7.5~10 m尺度）。综上所述，在高寒草甸应采取“围封+施肥+划破+补播”综合措施防控披针叶黄华的爆发，促进毒杂草型退化草地的恢复。     

Spatial and temporal comparison of selected cancers in dogs and humans, Michigan, USA, 1964-1994

Our aim was to investigate the geographic and time distributions of some biologically similar neoplasms in dogs and humans living in Michigan, USA, between 1964 and 1994. Our objective was to describe and compare the patterns of cancer in the two species while assessing the strength and dependence of those patterns. In this retrospective, registry-based study, histologically confirmed incident human and canine cancer cases were mapped, and second-order (K function) spatial analysis and one-dimensional nearest neighbor temporal analysis were performed on residence addresses and dates of hospital discharge/diagnosis. Included in the study were all 528 incident cases of canine lymphosarcoma, mammary adenocarcinoma, melanoma and spindle-cell sarcomas diagnosed at a veterinary teaching hospital between 1964 and 1994 having residence addresses in Ingham, Oakland, and Wayne Counties; and a stratified random sample of 913 incident human cases of comparable cancers diagnosed during the same time period from the same counties. Results suggest that processes determining spatial aggregation of cases in dogs and humans were not independent of each other, did not act uniformly over different geographic areas, operated at spatial scales <2000 m regardless of species, and tend to act upon dogs more strongly at shorter distances than on humans. Little evidence of interspecies concurrence of temporal clustering was found.