云贵鹅耳枥群落乔木种群生态位初探

木文应用Ｌｅｖｉｎ公式和王刚改进公式分别计测了贵阳喀斯特山地云贵鹅耳枥群落中乔木种群的生态位宽度和生态位重叠,并对这些种群的生态位关系及其对群落结构和动态的影响进行了分析。     

Global ecological niche conservatism and evolution in Olea species

Background and AimsClimate is an important parameter in delimiting coarse-grained aspects of fundamental ecological niches of species; evolution of these niches has been considered a key component in biological diversification. We assessed phylogenetic niche conservatism and evolution in 24 species of the family Oleaceae in relation to temperature and precipitation variables. We studied niches of 17 Olea species and 7 species from other genera of Oleaceae globally.MethodsWe used nuclear ribosomal and plastid DNA to reconstruct an evolutionary tree for the family. We used an approach designed specifically to incorporate uncertainty and incomplete knowledge of species’ ecological niche limits. We performed parsimony- and likelihood-based reconstructions of ancestral states on two independent phylogenetic hypotheses for the family. After detailed analysis, species’ niches were classified into warm and cold niches, wet and dry niches, and broad and narrow niches.Key ResultsGiven that full estimates of fundamental niches are difficult, we explore the alternative approach of explicit incorporation of knowledge of gaps in the information available, which allows avoidance of overestimation of amounts of evolutionary change. The result is a first synthetic view of evolutionary dynamics of ecological niches and distributional potential in a widespread plant family. Temperate regions of the Earth were occupied only by lineages that could derive with cold and dry niches; Southeast Asia held species with warm and wet niches; and parts of Africa held only species with dry niches.ConclusionsHigh temperature in Lutetian (Oligocene) and low temperature in Rupelian (Eocene) with major desertification events play important role for niche retraction and expansion in the history for Oleaceae clades. Associations between environmental niche characteristics and phylogeny reconstruction play an important role in understanding ecological niche conservatism, the overall picture was relatively slow or conservative niche evolution in this group.     

Niche breadth explains the range size of European-centred butterflies,but dispersal ability does not

Aim

The breadth of ecological niches and dispersal abilities have long been discussed as important determinants of species' range sizes. However, studies directly comparing the relative effects of both factors are rare, taxonomically biased and revealed inconsistent results.

Location

Europe.

Time Period

Cenozoic.

Major Taxa

Butterflies, Lepidoptera.

Methods

We relate climate, diet and habitat niche breadth and two indicators of dispersal ability, wingspan and a dispersal tendency index, to the global range size of 369 European-centred butterfly species. The relative effects of these five predictors and their variation across the butterfly phylogeny were assessed by means of phylogenetic generalized least squares models and phylogenetically weighted regressions respectively.

Results

Climate niche breadth was the most important single predictor, followed by habitat and diet niche breadth, while dispersal tendency and wingspan showed no relation to species' range size. All predictors together explained 59% of the variation in butterfly range size. However, the effects of each predictor varied considerably across families and genera.

Main Conclusions

Range sizes of European-centred butterflies are strongly correlated with ecological niche breadth but apparently independent of dispersal ability. The magnitude of range size–niche breadth relationships is not stationary across the phylogeny and is often negatively correlated across the different dimensions of the ecological niche. This variation limits the generalizability of range size–trait relationships across broad taxonomic groups.     

ORGANIZATION OF PREDATOR-PREY COMMUNITIES AS AN EVOLUTIONARY GAME

We consider a simple predator-prey model of coevolution. By allowing coevolution both within and between trophic levels the model breaks the traditional dichotomy between coevolution among competitors and coevolution between a prey and its predator. By allowing the diversity of prey and predator species to emerge as a property of the evolutionarily stable strategies (ESS), the model breaks another constraint of most approaches to coevolution that consider as fixed the number of coevolving species. The number of species comprising the ESS is influenced by a parameter that determines the predator's niche breadth. Depending upon the parameter's value the ESS may contain: 1) one prey and one predator species, 2) two prey and one predator, 3) two prey and two predators, 4) three prey and two predators, 5) three prey and three predators, etc. Evolutionarily, these different ESSs all emerge from the same model. Ecologically, however, these ESSs result in very different patterns of community organization. In some communities the predator species are ecologically keystone in that their removal results in extinctions among the prey species. In others, the removal of a predator species has no significant impact on the prey community. These varied ecological roles for the predator species contrasts sharply with the essential evolutionary role of the predators in promoting prey species diversity. The ghost of predation past in which a predator's insignificant ecological role obscures its essential evolutionary role may be a frequent property of communities of predator and prey.     

Ontogenetic diet shifts and diet overlap among three closely related neotropical armoured catfishes

Analysis of stomach contents of larvae, juveniles and adults of three closely related armoured catfishes in coastal plain swamps of Suriname, South America, revealed major ontogenetic diet shifts. Larvae of Hoplosternum littorale, H. thoracatum and Callichthys callichthys showed a restricted diet of rotifers and microcrustacea. Diets of juveniles and adults were more diverse, but large volumes of microcrustacea, aquatic insect larvae and detritus were always present. In all three species diet overlap was especially low between larvae and adults. The proportion of detritus in the stomach was positively related to fish size, which probably reflected the inability of larger size classes to separate effectively benthic invertebrate prey from bottom substrata, and not a specialization towards detritivory. Adults showed only minor seasonality in diet composition, and no effect of season on diet breadth. Interspecific diet overlap among larvae, juveniles and adults did not differ significantly from 1 (complete overlap). Lack of food partitioning was probably related to a similar morphology of the three catfishes. Intraspecific between-size class diet overlap was considerably lower than interspecific within-size class overlap. It is suggested that large interspecific diet overlap occurred because food was not limiting the populations of these catfish. However, the nest habitats of the three species differed.     

东亚大都市学生头型的比较研究

为了研讨居住区域的气候条件和社会经济环境对头型的影响,采用国际通用的人体测量法,调查测量了东亚三个国家四个集团３４７２名６－１７岁学生的头长和头宽,经统计学处理求得其平均值、头指数,回归方程,并作性差和地区差检验,其结果表明：中国大连学生为特圆头型,菲律宾马尼拉学生为圆头型,地理位置在大连和马尼拉之间的日本东京的学生的头型也位于二者之间,生活富裕集团的头长和头宽明显大于生活贫穷集团的学生,但头型二     

The ecology of ruffe,Gymnocephalus cernuus (Pisces: Percidae) introduced to Mildevatn,western Norway

Synopsis Diet, habitat use, diel and seasonal activity and a number of population parameters were studied on ruffe,Gymnocephalus cernuus, introduced to Mildevatn, western Norway. This lake is sited outside the natural range of the ruffe and has a lower fish diversity and a different fish species composition than within its native range. From June through September the ruffe was planktivorous and mainly caught at 4 to 6 m depth in the benthic zone. At other times of year ruffe was feeding on zoobenthos and caught deeper in the benthic zone. Ruffe was mainly day active. Zooplankton feeding during summer is the clearest difference compared to ruffe populations living within its natural range. Presence of large zooplankton organisms available for ruffe is suggested as the main reason for the difference found in food choice. The availability of large zooplankton is probably due to community structure caused by a predator and lack of interspecific competition for zooplankton in the deeper parts of the lake. Piscivorous brown trout.Salmo trutta, restrict the habitat of threespined stickleback,Gasterosteus aculeatus, to the zone of littoral vegetation, allowing high densities of larger zooplankton species likeBythotrephes longimanus to be present in the lake. Brown trout is present only in the upper light and well oxygenated parts of the lake, leaving a refuge for the ruffe, where they can feed on the rich zooplankton community.     

高原鼠兔与达乌尔鼠兔食物资源维生态位的研究

作者于１９９３年在青海省刚察县年诺索玛地区发现高原鼠兔（Ｏｃｈｏｔｏｎａ ｃｕｒｚｏｎｉａｅ）和达乌尔鼠兔（０．ｄａｕｒｉｃａ）在布哈河谷二阶同域且重叠分布之现象,并从这两种鼠兔的食物资源利用出发,研究了其生态位关系问题。在食物资源维上的生态位宽度（ＰＳ）,高原鼠兔为０．４７４４,达乌尔鼠兔为０．４９６４,即它们具有相近似的生态位宽度。这两种动物的生态位在食物资源谱维上的重叠值（ＦＴ）为０．８０９     

Succession,diversité et amplitude de niche dans les påturages du centre de la péninsule ibérique

Some diversity and niche amplitude parameters were applied to rangeland pastures of the Central Iberian Peninsula and to their succession stages after the periodical ploughing typical of the traditional management of these areas. Four different slopes within a large area of undulating terrain were selected for the monitoring of succession as they contained the characteristical geomorphological pattern of the area (denudation, transport and accumulation sectors).If we consider the total entropy theorem, H (E.P.)=H(E)+H(P/E), the total entropy of the slope H(E.P) and the entropy of species H(E) increase as succession progresses. As the value of the entropy of the sampling plots conditioned by the species H(P/E) is affected by the number of plots utilized, we employed the expression A=H(P/E)/log₂ number of plots, similar to Pielou's index for niche amplitude, W=H(P/E)/H(P).This values decreases with succession, indicating that plant species tend to occupy more definite sectors along the slope. The number of low entropy species H(P/E) _i or specialist species, confined to narrow sectors also increases. When computed separately within the different sectors niche amplitude results in small values for the low slope regions (accumulation sector). This effect becomes more pronounced when succession advances.

Nous remercions le Conseil d'Administration de La Paranza, propriétaire du Castillo de Vañuelas, et particulièrement Mrs. C. Hernandez-Ros et J. A. Léon-Vrquijò, pour les faeilités qu'ils ont données à cette équipe durant la réalisation de ce travail.     

Hominid paleoecology: The competitive exclusion principle and determinants of niche relationships

Some paleonanthropologists invoke the competitive exclusion principle programmatically in support of a single-species (or lineage) hypothesis of hominid evolution. Others apparently accept the association between competitive exclusion and a single species view, and develop multi-species interpretations using only taxonomic concepts. This paper demonstrates that the competitive exclusion principle itself is too assumption-bound to be appropriate for analyzing questions of hominid coexistence. Especially, the principle does not establish the ecological validity of the single-species hypothesis. Contrary to its immediate appearances, the principle has developed historically and analytically to predict and explain the evolution and maintenance of diversity in communities. Used in this manner it constitutes an important basis for the study of hominid paleoecology. Niche concepts necessary to demonstrate this are introduced, and competition and other factors that may have influenced the realized niches of sympatric hominid species are discussed. Nearly all modifications of the competitive exclusion principle that make it more realistic also illuminate factors that generate stable coexistence among competing species. These factors and their organizing theory establish the relevance of a broad data base to the analysis of hominid paleoecology; they should help to guide research on the ecology of early homonid species and their interrelationships.