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1.
Distributions of amphibian and reptile faunas were separately delimited on a 1:20 000 000 vegetation map of Northern Eurasia divided into 245 10-degree-longitudinal segments of native subzone within the USSR borders as of 1990. All reptile and amphibian species recorded in every segment were listed, and the Jaccard indices were calculated, and the similarity matrix was studied with cluster analysis. Hierarchic classifications were made: the amphibian one consisting of 3 faunistic regions, divided into 4 subregions, 7 biologic provinces, and 23 districts. The reptile classification includes 4 faunistic regions, 7 subregions, 18 provinces, and 14 districts. The reptile classification has 1.5 times more provincial and district subdivisions than amphibian one. Environmental factors correlating with faunistic nonuniformity were revealed. Our amphibian and reptile schemes are 1.9 and 3.5 times more informative than those proposed earlier and account for 75 and 91% of variance in the faunal similarity coefficient of specific areas, respectively (multiple correlation coefficients 0.87 and 0.95). Environmental factors can explain 84 and 93% of faunistic nonuniformity (correlation coefficients 0.95 and 0.96).  相似文献   

2.
For the purpose of zoning on the basis of fauna of terrestrial vertebrates, Northern Eurasia was considered within the boundaries of the Soviet Union in 1991 and divided into 245 mapping units. Mapping units were marked on the World Vegetation Map at a scale of 1: 20000000 in such a way that each mapping unit occupied a territory within the limits of a natural subzone having a latitudinal distance of 10°. A list of the vertebrate species was generated for each unit. Jaccard similarity coefficients were calculated for the lists; the coefficients were used as the basis for performing the cluster analysis of fauna of the mapping units. Based on the results of calculations, a hierarchical classification has been created. This classification includes 5 faunistic regions (regional groups of subregions), 6 subregions, 18 provinces, and 14 districts. Environmental factors that correlate with faunistic heterogeneity in the studied territory were described. The proposed zoning takes into account 57% of the variance of the similarity coefficients of the faunas of specific regions (coefficient of multiple correlation is 0.75). It is 2–2.5 times more informative than the previously developed schemes on particular groups of animals, which reflected, as the researchers thought at that moment, the heterogeneity of fauna of terrestrial vertebrates in general. Association with environmental factors and natural conditions may explain 82% of the heterogeneity of the fauna (correlation coefficient is 0.91). Comparing the results of zoning that were carried out for different classes of terrestrial vertebrates (amphibians, reptilians, birds, and mammals), we found significant similarity between causes of fauna heterogeneity (zonal features, provinciality, heat availability, and their combined effect). Nevertheless, differences in tolerance to the environment among the studied animal classes resulted in the substantial discordance of the boundaries of the described taxa and their hierarchy. This discordance was found during zoning. A classification of 1243 species of terrestrial vertebrates inhabiting the territory under study is performed based on the similarity of their occurrence (the average in the lower taxon faunistic zoning) and covers three types of distribution: Northern, Middle and Southern. These in turn are divided into 7 subtypes and 13 classes. The informative presentation of the classification is equal to 53% of the variance (correlation coefficient is 0.73).  相似文献   

3.
For the purpose of zoning on the basis of theriofauna, Northern Eurasia was considered within the boundaries of the Soviet Union in 1991 and was divided into 245 mapping units. Mapping units were marked on the World Vegetation Map at a scale of 1: 2000000. Each mapping unit occupied a territory within the limits of a natural subzone with a latitudinal distance of 10°. A list of mammal species was generated for each unit. Jaccard similarity coefficients were calculated for these lists; the coefficients were used as the basis for performing cluster analysis of theriofauna of the mapping units. The results of calculations were used to create a hierarchical classification, which includes three theriofauna regions divided into seven subregions. They were classified as island or mainland. All the subregions (except one) were delimited into 18 provinces and 17 districts; one of the districts was delimited into four subdistricts. Environmental factors that correlate with heterogeneity of theriofauna within the studied territory were described. The proposed zoning is 1.9–3 times more informative than previously developed schemes and takes into account 69% of the variance of the similarity coefficients of the faunas of specific regions (coefficient of multiple correlation is 0.83). The association with environmental factors and natural conditions may explain 83% of the heterogeneity of the theriofauna (correlation coefficient is 0.91). Comparing the results of zoning that were carried out for different classes of terrestrial vertebrates, we found significant similarity between causes of fauna heterogeneity (zonal features, remoteness, sun exposure, and their combined effect). In addition, the differences in tolerance to the environment among the studied animal classes resulted in substantial discordance of the boundaries of the described taxa and their hierarchy. This discordance was found during zoning. Because of this, general conclusions concerning the heterogeneity of the fauna of terrestrial vertebrates can be made only after the total analysis of their fauna is completed.  相似文献   

4.
A biogeographical division of northern Eurasia (within the USSR borders as of 1991) based on cluster analysis of the cyclostome and fish fauna composition at 597 sites listed in the Biodat database has been performed. The classification based on the Jaccard similarity coefficients included two regions, 12 subregions, eight provinces, and 11 districts. The division performed explained 67% of the variance of the similarity coefficients, this being 21% higher than the respective value for an earlier scheme (Berg, 1962) that covered a significantly greater territory. Correlation with the climatic regimes and environmental factors identified could explain 82% of fish fauna heterogeneity (the multiple coefficient of correlation was 0.91). The nonorthogonal relations with the temperature regime (67% of the variance of similarity coefficients), landscape and climatic zoning (58%), location within a specific river basin (57%), and provinciality (30%) were the most important factors.  相似文献   

5.
应用AFLP技术分析冬枣优良单株选择的遗传基础   总被引:3,自引:0,他引:3  
为探讨冬枣优良单株选择的遗传基础,本研究收集了河北、山东冬枣优良单株及对照冬枣共52株,以金丝小枣和尖枣做类外对照进行AFLP分子标记研究。实验选用16对M/E引物组合,共扩增出565条带,基于SM相似系数,利用UPGMA法对多态性谱带进行聚类分析,结果表明:冬枣优良单株群体内存在一定的遗传差异,但这种差异小于冬枣与金丝小枣和尖枣间的遗传距离,因此在聚类图中将冬枣、金丝小枣和尖枣分为3类;冬枣优良单株群体在聚类图中分成若干组,其中河北黄骅原始冬枣林古树和源于原始冬枣林的黄骅采穗圃冬枣优良单株,遗传距离相对较远;山东滨州各县的冬枣优良单株和沾化冬枣古树遗传距离较近,但存在个别变异较大的单株。上述结果证实冬枣是一个存在变异的群体、包含不同类型的品系,不同来源的冬枣优良单株存在一定的遗传变异,说明冬枣优良单株的优良性状不完全是立地条件和栽培技术引起的环境饰变,这一研究结果为冬枣的遗传改良和品种内选优提供了理论依据。  相似文献   

6.
冀中拗陷早第三纪孢粉组合及地质时代讨论   总被引:11,自引:1,他引:10  
本文在对700余口井的30000余块样品的分析数据进行系统整理,结合近年来地层研究最新成果,对冀中拗陷早第三纪孢粉化石群基本特征进行了系统研究,划分出十个组合带和十二个组合亚带,使之与精细地层研究工作相适应,从而更有地服务于生产实践和深入地进行地区地质分析。在参考构造,沉积、古气候、海平面变化,以及其它门类化石资料的基础上,对孢粉化石群产层的地质时代属性,以及下第三系内部的几条重要年代地层界线进行了讨论。同时,还对我国范围内其它区域相关问题进行了讨论。本文首次在“阶”的层次上,较系统地将中国陆相盆地下第三系与国际年代地层序列接轨。  相似文献   

7.
Abstract: The progress in the floristic study of the circumpolar Arctic since the 1940s is summarized and a new floristic division of this region is presented. The treeless areas of the North Atlantic and North Pacific with an oceanic climate, absence of permafrost and a very high proportion of boreal taxa are excluded from the Arctic proper. It is argued that the Arctic deserves the status of a floristic region. The tundra zone and some oceanic areas are divided into subzones according to their flora and vegetation. Two groups of subzones are recognized: the Arctic group (including the Arctic tundras proper and the High Arctic) and the Hypoarctic group. The Arctic phytochorion is floristically divided into sectors: 6 provinces and 20 subprovinces reflecting the regional features of each sector in connection with flora history, physiography and continentality-oceanity of the climate. Each sector is described and differentiated by a set of differential and co-differential species. The peculiarities of the Arctic flora are manifest in different ways in the various sectors, and endemism is not the universal criterion for subdivision.  相似文献   

8.
采用ISSR(Inter-simple Sequence Repeat)分子标记技术并应用NTSYSpc 2.10e生物软件对20株杏鲍菇菌种进行遗传聚类分析。结果表明,从22条引物中筛选出11条扩增条带清晰、多态性好的ISSR引物,共获得74个ISSR标记位点,51个多态性位点,多态比率为68.92%,产物片段大小在100~5 000 bp之间。聚类分析发现,遗传相似系数在0.828时,20株杏鲍菇菌种分为4个类群,当遗传相似系数达到0.896时,分为12个类群,杏528寿与其他菌种的亲缘系数最远,具有独立的遗传体系。  相似文献   

9.
Geographical distribution of African freshwater fishes   总被引:5,自引:0,他引:5  
Geographical distribution of African freshwater fishes is discussed with emphasis on the effects of major continental features, hydrographic history, and Pleistocene climatic fluctuations. Differences in the modes of dispersal and biological interactions among various categories of fishes, ecological as well as phyletic, have also had marked effects on distribution.
The African continent can be divided into ten ichthyofaunal provinces. The geography of these provinces and composition of their fish faunas is briefly described. The paper concludes with a consideration of the faunistic relationships of African lakes with endemic fishes.  相似文献   

10.
Fetuses of 24 women with normal pregnancies and 14 women with fetal intrauterine growth retardation (IUGR) were tested for shape and movement of the inner borders of the left ventricle (LV) by means of echocardiography. The LV contour was divided into 12 segments. The coefficient of variation (CV) of the movements of individual wall segments was calculated to assess regional nonuniformity of contractions of the LV wall. The ratio between the long and short LV axes was lower in the IUGR group (1.12 ± 0.12) than in the control group (1.75 ± 0.16). Nonuniformity of contractions was higher in the IUGR group (CV = 37.8 ± 17.6%) than in the control group (CV = 21.1 ± 9.9%, P < 0.01). The ratio of the early wave to the atrial wave of transmitral flow (E/A ratio) was lower in the IUGR group (0.69 ± 0.08) than in the control group (0.80 ± 0.08). A negative correlation between the CV and the global ejection fraction of the LV was observed in the fetuses of both groups. In addition, a negative correlation was demonstrated for the E/A ratio and the systolic-to-diastolic flow ratio (S/D ratio) in the umbilical artery. Changes in the shape, nonuniformity of contractions, and diastolic function of the heart in IUGR fetuses are considered to be an adaptation to increased afterload as a result of an elevated resistance of placental vessels.  相似文献   

11.
红花尔基地区沙地樟子松群落及其与环境关系研究   总被引:15,自引:1,他引:14  
通过野外调查,采用双向指示种分类(TWINSPAN)和除趋势典范对应分析(DCCA)方法。对内蒙古红花尔基地区沙地樟子松群落进行了分类和排序,并根据DCCA排序结果对樟子松群落和物种空间分布格局及其与环境因子之间关系进行定量分析。结果表明,应用TWINSPAN方法将该区沙地樟子松植被划分为6个类型。DCCA分析表明,海拔高度、地貌类型、群落盖度、土壤总碳含量、土壤总氮含量、乔木胸面积等因子对植物群落和物种分布格局影响明显。在DCCA排序图上,樟子松群落及物种的空间分布呈明显的聚集格局,可划分出不同的类群,并反映与环境因子之间具有密切的关系。对各类环境因子解释植被分布格局的作用进行了定量分解,指出地形因素是解释作用最强的变量,对未能解释部分的原因进行了分析。  相似文献   

12.
Camellia is an economically important ornamental plant that has many uses, such as in beverages, foods and medicines. We examined 15 Camellia cultivars in Wenzhou, China, using RAPD markers and measurements of three traits (petal color, flower diameter, blooming period). PCR amplification with 15 random primers produced 1935 bands, observed at 88 amplification loci; 77% of the amplified loci were polymorphic, with a mean of 4.5 polymorphic loci per primer. The similarity coefficient ranged from 0.5419 to 0.7933 among the 15 samples; the lowest value was between Manao (C. reticulata) and Feibai FR (C. japonica), and the largest value was between Chidan (C. japonica) and Yuanyang FG (C. japonica). Cluster analysis divided the 15 cultivars into two groups at the similarity coefficient of 0.65. A correlation was found between RAPD markers and petal color in the first group. No correlation was found between RAPD markers and the other traits (flower diameter, blooming period). This study provides information useful for the identification, classification, phylogenesis, and breeding of Camellia cultivars.  相似文献   

13.
A comparative analysis of the Orthopteran population in virgin and fallow lands of the European steppe has allowed finding out the colonization sources of the fallow lands: the inhabitants of the mesophytic intrazonal plant communities, including the formations of steppe bushes and polytopic species living in intact and disturbed steppe habitats have been found there. It has been shown that the structure of the Orthopteran population in the fallow lands in determined more by the composition of their plant cover than by the actual age of fallow lands or their zonal position. Fundamental changes in the structure of Orthopteran population are associated with the replacement of tall weed communities by an herb-grass cover; the faunistic similarity between the old fallow lands and zonal plots therewith increases. The abundance of Orthopteras in the fallow lands increases southward, while in zonal communities a reverse tendency is observed. The Orthopteran populations in the fallow lands of all the subzones are characterized by higher diversity and evenness if compared to zonal biotopes. A wide distribution of fallow lands with weed cover turns out to increase the faunistic and ecological diversity of the Orthopteran populations in the European steppe.  相似文献   

14.
A new planktic foraminiferal zonation has been established for the lower Danian, based on some of most expanded and continuous pelagic sections known to date (from Spain, Tunisia and Mexico). This biozonation is considered valid for low and middle latitudes. The maximum stratigraphical distribution of the index-species approximately coincides in all the studied sections. The index-species are abundant and easily recognizable. We propose the following biozones and subzones: Guembelitria cretacea Zone and the Hedbergella holmdelensis and Parvularugoglobigerina longiapertura subzones; the Parvularugoglobigerina eugubina Zone, which is subdivided into the Parvularugoglobigerina sabina and Eoglobigerina simplicissima subzones and the Parasubbotina pseudobulloides Zone with the Eoglobigerina trivialis and Subbotina triloculinoides subzones. A biomagnetostratigraphic correlation and calibration of the stratigraphical ranges of these species suggest that the biohorizons used to define the new biozonation are very isochronous, at least in the geographical areas analysed.  相似文献   

15.
中国食用向日葵种质资源遗传变异的RAPD及AFLP分析   总被引:7,自引:0,他引:7  
本研究采用RAPD和AFLP方法对23个中国不同地区的食用向日葵(Helianthus annuus L.)骨干品种进行了遗传变异分析,同时对两种标记系统进行了比较。26个RAPD引物产生了总计192条DNA条带,大小分布 于0.26kb-1.98kb之间,其中165条(86.12%)具有多态性,每条引物产生DNA条带的平均数为7.38。8对AFLP引物组合共产生了576条带,分布于100bp-500bp之间,其中的341条具有多态性,多态百分率为76.00%,每对引物组合产生DNA条带的平均数为72。RAPD方法检测的每位点有效等位基因数(1.76)大于AFLP(1.65),AFLP标记位点的平均多态性信息量(PIC)(0.38)低于RAPD标记位点PIC(0.41),但AFLP标记具有很高的多态性检测效率(Ai=38.52)。用RAPD标记分析23个食用向日葵材料的亲缘关系,Nei氏相似性系数分布在47.84%-82.06%,平均相似性系数为0.6495,而采用AFLP的Nei氏相似性系数分布在54.15%-83.52%,平均相似性系数为0.6884。RAPD数据的标准差为0.13,而AFLP数据的标准差为0.08。因此,采用RAPD和AFLP方法分析食用向日葵遗传变异,RAPD标记具有较低相似性系数和较高方差而AFLP则相反。源于两种不同标记的遗传相似矩阵的相关系数为0.51,说明采用RAPD和AFLP系统分析食用向日葵遗传变异得到的结果有一定的相关性,无论采用RAPD还是AFLP标记进行聚类分析,都将23个不同基因型的食用向日葵材料分成了三个类群。  相似文献   

16.
A 4-year study of Carabidae inhabiting potato fields in Northwestern Russia (Leningrad Province) revealed 58 species. Of these, 42 species were found in the areas with sandy soils, and 41 species, on loamy soils. The Jaccard’s faunistic similarity coefficient between the carabid complexes of fields with different types of soil was 43.1%. The ground-beetle complexes from fields on different soils differed in the species composition and the dominance structure. The number of individuals collected on sandy soils was almost 1.5 times as great as that collected on loamy soils; the latter biotopes were also characterized by a lower value of the Shannon species diversity index.  相似文献   

17.
The aim of this study was to unravel the relative role played by speleogenesis (i.e., the process in which a cave is formed), landscape‐scale variables, and geophysical factors in the determination of species richness in caves. Biological inventories from 21 caves located in the southeastern Iberian Peninsula along with partial least square (PLS) regression analysis were used to assess the relative importance of the different explanatory variables. The caves were grouped according to the similarity in their species composition; the effect that spatial distance could have on similarity was also studied using correlation between matrices. The energy and speleogenesis of caves accounted for 44.3% of the variation in species richness. The trophic level of each cave was the most significant factor in PLS regression analysis, and epigenic caves (i.e., those formed by the action of percolating water) had significantly more species than hypogenic ones (i.e., those formed by the action of upward flows in confined aquifers). Dissimilarity among the caves was very high (multiple‐site βsim = 0.92). Two main groups of caves were revealed through the cluster analysis, one formed by the western caves and the other by the eastern ones. The significant—but low—correlation found between faunistic dissimilarity and geographical distance (= .16) disappeared once the caves were split into the two groups. The extreme beta‐diversity suggests a very low connection among the caves and/or a very low dispersal capacity of the species. In the region under study, two main factors are intimately related to the richness of terrestrial subterranean species in caves: the amount of organic material (trophic level) and the formation process (genesis). This is the first time that the history of a cave genesis has been quantitatively considered to assess its importance in explaining richness patterns in comparison with other factors more widely recognized.  相似文献   

18.
目的 分析食品来源、患者来源及2种来源的副溶血性弧菌之间的PFGE图谱的关系,从分子流行病学角度探讨2种来源的副溶血性弧菌的关联.方法 收集患者和食品2种来源的副溶血性弧菌178株,经限制性内切酶SfiI酶切,用脉冲场凝胶电泳方法进行电泳,凝胶成像仪获得电泳图谱,利用BioNumerics软件对图谱进行聚类分析.结果 ...  相似文献   

19.
鹞落坪树生地衣群落数量分类及多样性   总被引:1,自引:0,他引:1  
采用主成分分析(PCA)对鹞落坪国家级自然保护区森林树生地衣进行了群落排序;应用Spearman 秩相关检对22种地衣进行了种间关联分析;以地衣多样性、相似性和均匀度等指数,对各地衣群落进行了比较.根据主成分分析结果并结合生境特征,保护区树生地衣形成了6种群落.Spearman秩相关检表明39个种对呈显著正相关,其中1...  相似文献   

20.
中国东北样带(NECT)东部森林区的植被与表土花粉的定量关系   总被引:10,自引:0,他引:10  
The eastern forest stands of Northeast China Transect (NECT) were chosen to study the quantitative relationships between vegetation and pollen in surface samples. The indices of A (association index),O(over-representation index),U(under-representation index),C(correlation coefficient) and R(representation coefficient) for each pollen type were calculated. The results indicated that the relationships between vegetation and pollen type in surface samples were significant and the correlation coefficients of 70% pollen types were more than 0.5(α=0.05); the similarity between pollen assemblage and plant community was good and coefficient of similarity was more than 50%. 69 pollen types found in the surface samples could be divided into four groups with TWINSPAN classification and PCA ordination according to A,O,U and C. The four groups reflected the pollination characteristic of plants and the state of pollen conserved in soil. Group 1 was the associative group which could accurately reflect the local vegetation; Group 2 was over-representative group which had high pollen percentage outproportional to vegetation; Group 3 was the under-representative group in which the pollen were hardly obtainable from the soil, and Group 4 was also an under-representative group, in which pollen were easily obtainable in soil where plants directly grow from. The study also showed that A was a parameter to rectify pollen data and it was easier to obtain than parameter R. The parameters A and R have close relation and their regression equation was: A=-0.0421R2+0.2425R+0.3926(r2=0.6021). These groups and indices provide a solid foundation for using pollen data in accurately reinstating vegetation.  相似文献   

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