长江,珠江,黑龙江鲢,鳙和草鱼原种种群形态差异

对长江、珠江、黑龙江的鲢、鳙、草鱼原种种群的十项形态特征,于高维空间上用统计方法进行判别分析,发现种群间具有显著差异,不同江河鲢、鳙的侧线鳞数也有明显不同。这些形态特征上的差异的大小与种群间的地理距离呈正相关。 根据上述显著性差异的特征,用模式分类法推导得鉴别程序,可在IBM-PC-AT计算机上对鱼逐尾自动判别鉴定其种群,除长江鲢外,准确率在75％～100％。     

The confusion between scale-defined levels and conventional levels of organization in ecology

Abstract. Conventional levels of organization in ecology can be hierarchically ordered, but there is not necessarily a time or space scale-dependent difference between the classes: cell, organism, population, community, ecosystem, landscape, biome and biosphere. The physical processes that ecological systems must obey are strictly scaled in time and space, but communities or ecosystems may be either large or small. Conventional levels of organization are not scale-dependent, but are criteria for telling foreground from background, or the object from its context. We erect a scheme that separates scale-ordered levels from the conventional levels of organization. By comparing landscapes, communities and ecosystems all at the same scale, we find that communities and ecosystems do not map onto places on the landscape. Rather, communities and ecosystems are wave interference patterns between processes and organisms interfering with and accomodating to each other, even though they occur at different scales on the landscape, and so have different periodicities in their waved behavior. Population members are usually commensurately scaled and so do not generally interact to give interference patterns. Populations are therefore tangible, oratleastcan be assigned a location at an instant in time.     

A note on the dynamics of montane virginPicea yezoensis forest in the Greater Khingan Mts,Northeastern China

The vertical growth ofLarix gmelini in the north of the Greater Khingan Mts., north-eastern China is very fast during the first 50 yr. ThoughPinus sylvestris var.mongolica shows a higher growth rate, it will be replaced by the larch population.Picea jezoensis is the most tolerant tree species and will replace all other trees.The fire cycle is 110–120 yr. Most of the montane areas from 800 to 1000 m a.s.l. are not occupied by spruce forest.There is a sapling bank with large numbers of saplings at ages below 20 yr in the understory in the spruce forest. The sapling bank is the key to maintain the steady state of the spruce forest. The persistent sapling bank in the life history of spruce governs the dynamics of the spruce forest controlled by the intensity and frequency of disturbances.The author is H. Q. Wu     

The population dynamics of the large pine aphid,Cinara pinea (Mordv.)

The large pine aphid, Cinara pinea lives exclusively on Pinus species, where it feeds on the foliated shoots of the current and previous year. The paper describes the development of a computer model designed to simulate the aphid's population dynamics on saplings in the controlled environment of the laboratory, i.e. in the absence of natural enemies. The model was able to account for about 80% of the variation in aphid numbers within and between trees over a three month period. Sensitivity analysis revealed that the number of pine aphids is limited primarily by nymphal emigration, the operation of which is sensitive both to density and to plant quality as reflected in aphid growth rates. Of secondary importance are changes in reproduction acting through increased reproductive delay, again a result of altered growth rates and adult size. Development, too, has an important secondary influence. Contrary to expectation and conventional belief, however, alate production proved to be of negligible importance, either in limiting or regulating population numbers. Alatae are produced in too few numbers and for too short a period to significantly alter the pattern of population change.     

A stochastic discrete generation birth,continuous death population growth model and its approximate solution

This paper describes a single species growth model with a stochastic population size dependent number of births occurring at discrete generation times and a continuous population size dependent death rate. An integral equation for a suitable transformation of the limiting population size density function is not in general soluble, but a Gram-Charlier representation procedure, previously used in storage theory, is successfully extended to cover this problem. Examples of logistic and Gompertz type growth are used to illustrate the procedure, and to compare with growth models in random environments. Comments on the biological consequences of these models are also given.Currently at Department of Mathematics, University of MarylandWork partially supported by the Danish Natural Science Research Council and Monash University     

An alternative to ITS, a hypervariable, single-copy nuclear intron in corals, and its use in detecting cryptic species within the octocoral genus Carijoa

Here we report a highly variable nuclear marker that can be used for both soft and stony corals. Primers that amplify a ∼177 bp fragment from the nuclear gene encoding the 54 kDa subunit of the signal recognition particle (SRP54) were developed for the octocoral genus Carijoa. Cloning results from 141 individuals suggest that this hypervariable nuclear locus is a single-copy gene. Sequencing revealed a potential cryptic species previously thought to be Carijoa riisei. Results from an Analysis of Molecular Variance (AMOVA) based on mitochondrial DNA (mtDNA) explained <10% of the variation between Atlantic and Pacific samples of C. riisei (F _st = 0.47), whereas the same comparison with SRP54 explained >33% of the variation (F _st = 0.54). Using previously reported degenerate primers for SRP54, high levels of sequence variation were found at this locus across both scleractinian and octocorals. For example, pairwise sequence divergence within octocorals was ∼8–13 times greater with SRP54 than with mtDNA, and, up to 2.8% pairwise sequence divergence was found in SRP54 among individuals of Pocillopora whereas no variation at all was found in mtDNA markers. This case study with the octocoral C. riisei shows that variation in SRP54 appears sufficient to address questions of phylogeography as well as systematics of closely related species.     

Densities of microtime rodents along a pollution gradient from a copper-nickel smelter

Population densities of microtine rodents were studied along an air pollution gradient in the Kola Peninsula, Russia, by long-term and short-term trapping. The study area is affected by high sulphur dioxide and heavy metal emissions from the Severonikel copper-nickel smelter in Monchegorsk. The density of Clethrionomys rufocanus, the most abundant vole species in the area, was lowest close to the smelter and increased with distance up to the farthest, less polluted trapping sites. Clethrionomys glareolus, C. rutilus and Lemmus lemmus were absent from the most severely damaged area and were also scarce at the moderately polluted area 28 km south of the smelter. Although the population of C. glareolus has previously been cyclic at the moderately polluted area, we were unable to demonstrate any regular cycle. The most likely explanation for the low number of microtine rodents in the damaged and moderately polluted areas in a decrease in the quantity of important food plants: epiphytic lichens for C. glareolus and possibly C. rutilus, mosses for L. lemmus and seed plants, especially Vaccinium myrtillus, for C. rufocanus. Close to the smelter, direct toxic effects of heavy metals may also reduce population densities. The results show that pollutants may change the relative proportions of microtine species.     

Multivariate analysis of anthropometric data and classifications of British Columbian natives

Anthropometric data collected in native populations of British Columbia in the late 19th century by Franz Boas were analyzed by two multivariate techniques. Multivariate analysis of variance was used to test physical classificatory units devised by Boas and an ad hoc classification based on local cultural units. Both were found to have some empirical validity. Mahalanobis' D (Mahalanobis, '30) was computed between pairs of local groups, for both sexes. From these a matrix of differences was prepared and diagrams drawn to illustrate phenetic relationships among samples. By this means one cluster of groups, Interior B.C. peoples, could be distinguished and other local samples appeared distinctly different from each other. It was concluded that in the absence of genealogical data by which to identify local populations, local cultural units are preferable to more inclusive units for making empirical comparisons and classifications.     

Population growth and structure in a variable environment

When a population experiences temporal changes in the vital rates due to environmental or biotic variation, change is not only expected in the rate of population growth but also in the structure of the population. In this study we present a method for transforming observed patterns (notably how vital rates change with temperature) into functions that can be used in population growth models and analysis of population structure. The method is exemplified by applying it to cohort studies in different constant temperatures of four species of aphids, Lipaphis erysimi (K.), Metopolophium dirhodum (Wlk.), Rhopaliosiphum padi and Macrosiphum avenae (F.). We use piece-wise linear functions to transform the vital rates of the cohort studies. The lifespans are divided into phases, each phase having linear rates. A projection matrix is formulated, where the elements are temperature dependent fecundities, survivorships and developmental rates. The major result is, contrary to what theory predicts as reasonable (Caswell 1989), that population structure of these aphid species will become almost fixed although the temperature varies. This result is consistent with findings of earlier field studies (Wiktelius 1982). A fixed population structure implies that it is possible to calculate the population growth rate on the basis of intrinsic rates of increase. By simulating different temperature regimes we also show that initial oscillations in the population structure dampen out after a few days. After initial oscillations, calculations of population growth using intrinsic rates of increase are consistent with calculations made by a matrix model.