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于1997-1999年检测了俄联邦卡尔梅克(Kalmyki)共和国ChernieZemly半干旱草原由10个物种组成的啮齿类群落。该区域的植被特点是家畜大量减少后形成的恢复植被。我们的任务之一就是了解不同啮齿动物的生境需求,以预测不同物种对环境变化的特异性反应。我们也检测了群落空间结构、生态位参数和物种多样性。逐步回归分析表明,各种啮齿动物的空间分布仅部分地决定于已知环境因子(2-6个变量)。虽然方程式具有强显著性,但决定系数R2很低,不超过18%。对于大多数种类,这种结果可由最近草原扩大而来的生境异质性降低解释。物种生境选择条件和资源的明显低水平可能是由物种对环境变化的惯性反应造成的。判别函数分析和主分量分析结果表明,群落结构以及单个物种的生态位参数在不同年间并不稳定。空间分层结构在种间中等和低重叠的高物种多样性年度表现明显。多样性、生态位组成和生态位宽度分析结果表明,不同物种对环境条件和资源变化的反应具有不同的个性化方式。同时,物种对环境动态的明显个性化反应成为物种多样性定向变化的原因。限定空间和相对单一条件下的结果表明,啮齿类α多样性与生境结构复杂性呈正相关,而与生境生产力特征呈负相关。观察表明,卡尔梅克国草原扩大伴随着初级生产力的升高和生境异质性的降低。随着时间的推移会导致大多数草原和半干旱区域啮齿类多样性的降低,并形成动物区系核心.  相似文献   

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植物种群生态学中的构件理论   总被引:59,自引:0,他引:59  
植物种群生态学中的构件理论黎云祥,刘玉成,钟章成(四川师范学院生物系,南充637002)(西南师范大学生物系,重庆630715)ModularTheoryinPlantPopulationEcology.¥LiYunxiang;LiuYucheng(...  相似文献   

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外来斑潜蝇入侵和适应机理及管理对策   总被引:8,自引:1,他引:8  
陈兵  赵云鲜  康乐 《动物学研究》2002,23(2):155-160
重要外来斑潜蝇(美洲斑潜蝇Liriomyza sativae Blanchard,南美斑潜蝇L.huidobrensis Blanchard)已对我国蔬菜和花卉生产造成了重大的经济损失。介绍了我国外来斑潜蝇的主侵形势,入侵途径和特点及采取的防治对策;分析了外来斑潜蝇在我国与寄主植物,气候,人类活动等作用过程中的适应机理,并针对我国目前外来斑潜蝇入侵现状提出了可行的管理措施,以期对预防了管制我国外来生物入侵提供参考。  相似文献   

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Based on the investigation of 1ha plot, the primitive monsoon forest on the valley of lower Luzhi River in Yunnan was studied. The height of the community is 15-20m, and tree layers are divided into 2 layers, which is dominated by deciduous tree species Lannea coromandelica and evergreen tree species Cipadessa cinerascens. One hundred and sixteen vascular plant species were recorded from the plot, including 36 tree species, 14 shrub species, 43 herbaceous species, 43 liana species and 2 epiphyte species. Shannon Wienner index is 22824 and Simpson index is 08321 from the 1ha plot. Total 1764 trees individuals with DBH ≥1cm were recorded in the plot. This community is dominated by phanerophytes. The forest is dominated by the microphyllous species which makes up 3932% of the total. The forest is also dominated by the species with simple leaves (make up 7350%), papery leaves (make up 6923%), none caudate leaves (make up 8120%) and entire leaves (make up 6752%). The species/area curve shows that it is flatten at 2000m2, which is suggested to be the minimum sampling area for the forest. This community could be recognized as Lannea coromandelica Cipadessa cinerascens formation.  相似文献   

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略谈理论和模型在生态学中的作用   总被引:4,自引:1,他引:4  
略谈理论和模型在生态学中的作用邬建国(美国内华达大学系统、荒漠研究所生物科学中心)OverviewontheRoleofTheoryandModelinEcology.¥WuJianguo(BiologicalSciencesCenter,Deser...  相似文献   

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西双版纳热带山地季风常绿阔叶林的群落生态学研究   总被引:11,自引:2,他引:11  
依据5个25m×20m样地的调查资料, 对西双版纳热带山地的季风常绿阔叶林的群落结构、种类组成、生活型构成、多样性、种面积关系等进行了分析研究,结果显示西双版纳热带山地的季风常绿阔叶林主要由壳斗科、大戟科、茶科和樟科等树种组成; 乔木树种种类丰富,灌木、草本、藤本种类相对较少;随乔木径级的增大,个体/种的数量逐渐减小;群落中以中叶、全缘、革质、非尾尖、常绿植物占优势; 群落种-面积关系曲线在取样面积为1 500m2时开始趋于平缓,意味着该取样面积可以考虑作为群落最小表现面积.  相似文献   

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安徽沿江城郊蔬菜地土壤动物群落生态学研究   总被引:5,自引:6,他引:5  
对沿江蔬菜地土壤动物群落的研究表明 ,1 82 2 2个标本分隶于 6门 1 4纲 2 9目72科 ,其中以弹尾目、螨目和线虫纲动物数量最多 .同种青菜地土壤动物群落组成丰富性( S)、多样性、均匀性指数值以 7月最大 ,1 2月最小 ;个体数、密度和优势性值以 1月最大 .在不同品种菜菜地 ,8月以青菜和韭菜 S值最大 ,豇豆、毛豆次之 ,萝卜最小 .但随着不同品种生长周期的变化 ,土壤动物群落结构也发生变化 .肥力高的黑砂土 ,土壤动物群落各项指标高于沙洲菜地  相似文献   

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  1. Detailed understanding of the mechanisms enabling or limiting the impacts of invasive generalist predators is needed. Harmonia axyridis is an invasive generalist coccinellid predator that may have destabilised coccinellid communities worldwide and is an excellent candidate for investigating invasion dynamics.
  2. We evaluated four hypotheses: (1) Nine years after being detected in Central Brazil, Ha. axyridis has dominated the coccinellid community. This is facilitated by (2) its broader aphid prey range than the other aphidophagous coccinellids, (3) its superiority as an asymmetrical intraguild predator, and (4) the invasibility of the present coccinellid community.
  3. We sampled the invertebrate communities associated with six organic vegetable farms in Brazil during 2017 and 2018, conducted a feeding trial to measure prey niche breadth and overlap, and estimated intra- and interspecific interaction strengths corresponding to first-order Lotka-Volterra parameters to evaluate the strength of intraguild predation and create a community matrix.
  4. We found (1) Ha. axyridis comprised ≤8.3% of the coccinellid community. (2) Hi. convergens had the broadest prey niche and dominated the prey niche of Ha. axyridis. (3) We could not determine from the population data if Ha. axyridis was the dominant intraguild predator because its density was too low and constant. (4) The community matrix indicated that the present-day coccinellid community was stable.
  5. We conclude Ha. axyridis has not become invasive in Central Brazil, in part because it does not have the broadest prey niche breadth and the present coccinellid community is stable to the present perturbation of Ha. axyridis.
  相似文献   

11.
对罗扎河下游鲜为人知的落叶季雨林进行了群落生态学研究,结果表明:罗扎河下游落叶季雨林群落高度在15~20m之间;群落乔木层以厚皮树(Lannea coromandelica)、一担柴(Colonafloribunda)、粗糠柴(Mallotus philippensis)、毛果扁担杆(Grewia eriocarpa)、灰毛浆果楝(Cipadessa cinerascens)等树种为优势种;灌草层以刚莠竹(Microstegiumciliatum)盖度最大,其余如飞机草(Eupatoriumodoratum)、藿香蓟(Agera-tumconyzoides)、蹄盖蕨(Athyriumsp.)等种的盖度也比较大;群落中乔木和附生、藤本植物种类较少,而灌木和草本植物种类较多;多数乔木层植株胸径在5~10cm之间,大径级乔木比较少,即使群落中的优势种也主要是通过较多数量的中小径级个体体现出来。多样性指数计算表明,本落叶季雨林的生物多样性指数虽然比典型热带山地雨林为低,但大致相当于季风常绿阔叶林。  相似文献   

12.
Mesquita DO  Colli GR  Vitt LJ 《Oecologia》2007,153(1):185-195
We compare lizard assemblages of Cerrado and Amazonian savannas to test the ecological release hypothesis, which predicts that niche dimensions and abundance should be greater in species inhabiting isolated habitat patches with low species richness (Amazonian savannas and isolated Cerrado patches) when compared with nonisolated areas in central Cerrado with greater species richness. We calculated microhabitat and diet niche breadths with data from 14 isolated Cerrado patches and Amazon savanna areas and six central Cerrado populations. Morphological data were compared using average Euclidean distances, and lizard abundance was estimated using the number of lizards captured in pitfall traps over an extended time period. We found no evidence of ecological release with respect to microhabitat use, suggesting that historical factors are better microhabitat predictors than ecological factors. However, data from individual stomachs indicate that ecological release occurs in these areas for one species (Tropidurus) but not others (Ameiva ameiva, Anolis, Cnemidophorus, and Micrablepharus), suggesting that evolutionary lineages respond differently to environmental pressures, with tropidurids being more affected by ecological factors than polychrotids, teiids, and gymnophthalmids. We found no evidence that ecological release occurs in these areas using morphological data. Based on abundance data, our results indicate that the ecological release (density compensation) hypothesis is not supported: lizard species are not more abundant in isolated areas than in nonisolated areas. The ecology of species is highly conservative, varying little from assemblage to assemblage. Nevertheless, increases in niche breadth for some species indicate that ecological release occurs as well. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

13.
Abstract. A distinctive feature of Australian vegetational history is the abruptness of change since European settlement, involving the influx of exotic species and the imposition of exogenous disturbances which are novel in both intensity and character. This can produce two sources of habitat variability: the natural patterns arising from environmental variation, as well as an overlying effect of disturbance. The relative importance of these two types of variables were compared in temperate herbaceous vegetation. Canonical Correspondence Analysis showed that environment and disturbance had similar contributions to floristic variability. Individually, lithology, altitude and soil disturbance were the strongest variables while slope position, grazing and water enrichment were slightly less important. Despite generally low levels of site specificity, groups of species associated with lithology, slope position, altitude and different disturbance regimes were identified. Exotic species were associated with higher levels of disturbance, but showed levels of environmental specialization similar to the native component. Through combination of this analysis with a previous analysis of species richness for the same data set, it became evident that environmental variation mostly resulted in species substitutions while disturbances led to losses of species, with partial replacement by exotics. Synthesizing these results, we identified three broad groups in relation to tolerance of levels of exogenous disturbance: (1) intolerant species - native taxa intolerant of severe disturbances and constituting the species - rich component of the vegetation; (2) tolerant species - exotic and native taxa occurring at both disturbed and undisturbed habitats and (3) disturbance specialists - predominantly exotic species, correlated with high levels of disturbance.  相似文献   

14.
This article presents a theoretical foundation for integrating three otherwise disparate areas of human thought and understanding: technology, ecology, and economics. The article presents the mathematical foundations for quantifying the biophysical (mass, energy, and informational) aspects of economic production systems and their interaction with natural systems. These mathematical relationships are required for the on-going ecological and economic design of technological production networks by enterprise management, thereby extending the scope and scale of quantitative engineering design from the domain of individual technologies to networks of technologies at enterprise, corporate, and industrial levels of technological organization.
The analytical framework extends the practical utility of ecology, as an applied natural science, from passive environmental monitoring and prediction to active institutional participation in an informational feedback control strategy pursuant to economically abating the ecological risks of industrial growth, development, and modernization at local, regional, and global levels of ecological organization. And it provides the applied natural-science underpinnings and the informational feedback control institutions required to support economics as an applied social science. In this context ecological risk-control pricing is presented as a supplement to conventional economic policies at local, regional, and national levels of economic organization.  相似文献   

15.
The distinction between the context ofdiscovery and the context of justificationrestricts philosophy of science to the rationalreconstruction of theories, and characterizesscientific discovery as rare, theoreticalupheavals that defy rational reconstruction. Kuhnian challenges to the two contextsdistinction show that non-rational elementspersist in the justification of theories, butgo no further to provide a positive account ofdiscovery. A gradualist theory of discoverydeveloped in this paper shows, with supportfrom ecological cases, that discoveries areroutinely made in ecology by extending modelsto new domains, or by making additions toearlier models. The logic of discovery isphilosophically accessible once it isappreciated that model truth is presumed, evenif counterfactually, in ecologists' applicationof models. A gradualist view shows thatmodels' heuristic power routinely leads todiscoveries.  相似文献   

16.
Interaction networks (IN) have been used in ecology to model different kinds of interactions in ecological communities. Historically there are two basic ways to construct an IN: binary networks (BN) that represent unweighted links among species in the web, and weighted networks (WN) that weight each interaction among species by its relative or absolute frequency in the web. We call binary reduction the transition from WN to BN which obviously entails loss of information. We performed an analysis with 69 WN on which we worked the binary reduction. For both WN and BN we computed: the coefficient of variation, skewness, kurtosis, Shannon entropy and the Gini coefficient on the population statistics. We also computed the dependence asymmetry, the pairwise Jaccard distance and two different measures of nestedness, (W)NODF and τ-temperature, for the WN and BN. From correlations between the values for WN and BN we concluded that, for most of the indices, the loss of information due to the binary reduction is not significant. Using a statistical evaluation, for most indices, BN give similar results to their corresponding WN.  相似文献   

17.

Background

Host-microbe and microbe-microbe interactions are often governed by the complex exchange of metabolites. Such interactions play a key role in determining the way pathogenic and commensal species impact their host and in the assembly of complex microbial communities. Recently, several studies have demonstrated how such interactions are reflected in the organization of the metabolic networks of the interacting species, and introduced various graph theory-based methods to predict host-microbe and microbe-microbe interactions directly from network topology. Using these methods, such studies have revealed evolutionary and ecological processes that shape species interactions and community assembly, highlighting the potential of this reverse-ecology research paradigm.

Results

NetCooperate is a web-based tool and a software package for determining host-microbe and microbe-microbe cooperative potential. It specifically calculates two previously developed and validated metrics for species interaction: the Biosynthetic Support Score which quantifies the ability of a host species to supply the nutritional requirements of a parasitic or a commensal species, and the Metabolic Complementarity Index which quantifies the complementarity of a pair of microbial organisms’ niches. NetCooperate takes as input a pair of metabolic networks, and returns the pairwise metrics as well as a list of potential syntrophic metabolic compounds.

Conclusions

The Biosynthetic Support Score and Metabolic Complementarity Index provide insight into host-microbe and microbe-microbe metabolic interactions. NetCooperate determines these interaction indices from metabolic network topology, and can be used for small- or large-scale analyses. NetCooperate is provided as both a web-based tool and an open-source Python module; both are freely available online at http://elbo.gs.washington.edu/software_netcooperate.html.  相似文献   

18.
In the last two centuries, several species of Australian eucalypts (e.g. Eucalyptus camaldulensis and E.␣globulus) were introduced into the Iberian Peninsula for the production of paper pulp. The effects of the introduction of exotic root-symbitotic fungi together with the eucalypts have received little attention. During the past years, we have investigated the biology of ectomycorrhizal fungi in eucalypt plantations in the Iberian Peninsula. In the plantations studied, we found fruit bodies of several Australian ectomycorrhizal fungi and identified their ectomycorrhizas with DNA molecular markers. The most frequent species were Hydnangium carneum, Hymenogaster albus, Hysterangium inflatum, Labyrinthomyces donkii, Laccaria fraterna, Pisolithus albus, P. microcarpus, Rhulandiella berolinensis, Setchelliogaster rheophyllus, and Tricholoma eucalypticum. These fungi were likely brought from Australia together with the eucalypts, and they seem to have facilitated the establishment of eucalypt plantations and their naturalization. The dispersion of Australian fungal propagules may be facilitating the spread of eucalypts along watercourses in semiarid regions increasing the water lost. Because ectomycorrhizal fungi are obligate symbionts, their capacity to persist after eradication of eucalypt stands, and/or to extend beyond forest plantations, would rely on the possibility to find compatible native host trees, and to outcompete the native ectomycorrhizal fungi. Here we illustrate the case of the Australasian species Laccaria fraterna, which fruits in Mediterranean shrublands of ectomycorrhizal species of Cistus (rockroses). We need to know which other Australasian fungi extend to the native ecosystems, if we are to predict environmental␣risks associated with the introduction of Australasian ectomycorrhizal fungi into the Iberian Peninsula. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

19.
The success of invasive aquatic species is determined by a variety of attributes such as wide environmental tolerance, high genetic variability, short generation time, early sexual maturity, high reproductive capacity, and a broad diet. Usually, introduced species, after some time lag since inoculation, show an exponential population increase and expansion. Maintenance of the immigrant species at a high population level will be dependent on interspecific competition with native species and availability of habitat and food. Eventually, the immigrant population may decline, for instance due to increased predation pressure, parasite infestation or loss of genetic vigour. These characteristic patterns in invasive species are reviewed for the case of the North American spionid polychaete Marenzelleria cf. wireni in the Dutch Wadden Sea. This species was first recorded in estuaries and coastal waters of the European continent in the Ems estuary (eastern Dutch Wadden Sea) in 1983. In the western part of the Dutch Wadden Sea the first specimens were found in 1989. The Ems estuary population showed the typical lag-phase, explosive increase, stabilisation, and eventual decline. In the western part of the Dutch Wadden Sea the latter two phases have not yet developed. The strong development and stabilisation of the population in the Ems estuary may have been caused by the availability of a yet not utilised food source. The species' final decline remains largely unexplained.  相似文献   

20.
影响水稻纹枯病流行、危害的因子分析   总被引:8,自引:1,他引:7  
以连作早稻为研究对象,对影响水稻纹枯病发生、危害有关的因子,即品种、施氮肥量、气象因素、为害损失、发病时间、病情程度及药剂等作了系统的定量研究.结果表明,品种间存在抗病性和危害损失程度上的差异;施氮肥量与发病程度关系密切;气象因素中以日均温和雨日频率与病害流行速率关系密切;发病时间与为害损失率相关性不明显,药剂防治效果与控病时间、病情基数有关.  相似文献   

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