中国不同地理区域鸟兽物种丰富度的相关性

生物类群之间物种丰富度的相关性研究是当前物种多样性研究中的热点问题之一,目前,中国尚无相关的研究报道。我们收集了中国三种区域类型：动物地理亚区、行政区和保护区的鸟兽名录,分析了行政区与保护区、动物地理区和经纬度带中鸟兽物种数比值及其相关性。 结果表明：不同区域、动物地理区和经纬度带中鸟兽物种数都显著相关。保护区尺度鸟兽物种 数的相关系数为0.818和动物地理区中的华北区为0.768,其他所有区域和地理区域的鸟兽物 种数的相关系数都高于0.850。因此,鸟兽物种数的相关关系在一定程度上具有预测价值。我们发现不同区域鸟兽物种数比值无显著性差异;但是,不同区域间鸟兽物种数 比值差异显著。该比值在中国呈中间低四周高的分布趋势,其中东北地区最高。我们还利用历史累积调查数据与非历史累积调查数据进行了鸟兽物种数比值及其相关性分析,发现利用累积数据计算的相关性低于非累积数据计算的相关性,但利用累积数据计算的鸟兽物 种数比值高于非累积数据计算的比值。最后,探讨了为什么鸟类与兽类的物种数目会相关。我们根据物种－面积公式,S=CA^Z,导出了两个生物类群物种丰富度的相关关 系式。利用全国不同区域数据拟合,得到Z₁/Z₂＝0.913,Z₁/Z₂接近于1。于是 ,C₁/C2可视为近似等于R_am。本研究可推广到其他不同生物类群物种。物种数量的相关关系为快速评估区域的物种多样性提供了一条途径。     

Pteridophyte species richness in Andean forests in Bolivia

I assessed the magnitude and distribution of pteridophyte species richness on the eastern Andean slope in Bolivia based on 676 study plots of 400 m² each in forest habitats at 65 study sites. In total 755 species were recorded, including 426 (56%) epiphytes and 598 (79%) terrestrials, with 266 species (35%) recorded under both groups. Mean number of species per plot at a given site varied from 0 to 31.1 for epiphytes, 0 to 20.9 for terrestrials, and 0 to 47.9 for all species combined. The highest numbers of species recorded at a given study site were 110 epiphytes, 101 terrestrials, and 167 species in total. While overall there were more terrestrial than epiphytic species, at individual sites and plots the reverse was true, indicating that terrestrial species tended to be more patchily distributed than epiphytes. Despite high survey intensity, many species went unrecorded; the minimum estimate of total species richness obtained through extrapolation was 975 species overall, including 559 epiphytes and 880 terrestrials. A correlation analysis of species richness to 14 environmental parameters revealed a highly positive correlation to mean annual precipitation and bryophyte cover on tree branches (a proxy for air humidity). Significant correlations to other parameters (e.g. human impact, canopy height, etc.) reflected the covariance of these factors with precipitation and bryophyte cover. Despite a lack of data on the pteridophyte communities from much of the Bolivian Andes, it appears that in most of the countries, pteridophyte diversity can be protected by focussing the most humid parts of the Andean forests.     

Toward a better understanding of the regional causes of local community richness

Despite widespread acknowledgement that local ecological communities are profoundly shaped by regional-scale influences, including evolutionary and biogeographic processes, this perspective has yet to be widely incorporated into ecological research. Drawing on recent research, we propose four steps towards making regional influences a stronger part of research on the richness of local communities: (1) identifying the regional-scale causes of variation in species richness in the systems ecologists study; (2) testing for effects of regional richness on local richness, using improved observational and experimental analyses to overcome earlier problems; (3) simultaneously analysing environmental influences on regional and local species richness as well as the influence of regional richness on local richness and (4) considering the potential reciprocal effects of local processes on regional richness. In conclusion, we suggest some ways that similar approaches could be applied to other aspects of community structure beyond species richness.     

Regional patterns of diversity and estimates of global insect species richness

The total number of insect species in the world is an important if elusive figure. We use a fresh approach to estimate global insect species richness, based on biogeographic patterns of diversity of well or better documented taxa. Estimates generated by various calculations, all variations on a theme, largely serve to substantiate suggestions that insect species are likely to number around 10 million or less.     

A multiple-site similarity measure independent of richness

The Diserud–Ødegaard multiple-site similarity index makes use of data on species shared by two or more sites, but produces equal similarity values in two different circumstances: species loss and true species turnover. We developed a new multiple-site similarity measure, which is independent of richness and performs better than the Diserud–Ødegaard index under conditions of equal richness between sites, because it discriminates between situations in which shared species are distributed evenly among sites or concentrated in few pairs of sites. We conducted several simulations to assess the relative performance of both the indices. The use of the new measure is recommended, enabling the simultaneous analysis of turnover and richness gradients based on two independent measures.     

Exploring the phylogenetic history of mammal species richness

Aim At broad geographical scales, species richness is a product of three basic processes: speciation, extinction and migration. However, determining which of these processes predominates is a major challenge. Whilst palaeontological studies can provide information on speciation and extinction rates, data are frequently lacking. Here we use a recent dated phylogenetic tree of mammals to explore the relative importance of these three processes in structuring present‐day richness gradients. Location The global terrestrial biosphere. Methods We combine macroecological data with phylogenetic methods more typically used in community ecology to describe the phylogenetic history of regional faunas. Using simulations, we explore two simple phylogenetic metrics, the mean and variance in the pairwise distances between taxa, and describe their relationship to phylogenetic tree topology. We then use these two metrics to characterize the evolutionary relationships among mammal species assemblages across the terrestrial biome. Results We show that the mean and variance in the pairwise distances describe phylogenetic tree topology well, but are less sensitive to phylogenetic uncertainty than more direct measures of tree shape. We find the phylogeny for South American mammals is imbalanced and ‘stemmy’ (long branches towards the root), consistent with recent diversification within evolutionarily disparate lineages. In contrast, the phylogeny for African mammals is balanced and ‘tippy’ (long branches towards the tips), more consistent with the slow accumulation of diversity over long times, reflecting the Old World origin of many mammal clades. Main conclusions We show that phylogeny can accurately capture biogeographical processes operating at broad spatial scales and over long time periods. Our results support inferences from the fossil record – that the New World tropics are a diversity cradle whereas the Old World tropics are a museum of old diversity.     

Functional group dominance and not productivity drives species richness

Background: There is a lack of consensus about the productivity–richness relationship, with several recent studies suggesting that it is not productivity but other factors that are the important drivers that determine species richness.

Aims: Here, we examine the relationship between productivity, functional group dominance and plant species richness at the plot scale in Tibetan Plateau meadows. These alpine meadows are ideal to examine the species productivity-richness relationship because they have a very high species richness, a large gradient in productivity, and can be dominated by either graminoids (grasses and sedges) or forbs.

Methods: We measured plant species richness and above-ground biomass along a natural gradient of functional group abundance in 44 plots distributed across five natural, winter-grazed but otherwise undisturbed sites in the eastern part of the Qing-Hai Tibetan Plateau, in Gansu province, China in 2008.

Results: Graminoid abundance (i.e. graminoid biomass as percent of the total above-ground biomass) explained 39% of plot differences in species richness while neither productivity nor the biomass of the three most abundant plant species, either individually or combined, were a significant predictor of species richness.

Conclusions: Our results show that within these alpine meadows, a shift from graminoid to forb dominance, rather than the individual dominant species or productivity itself, is strongly correlated with species richness. Thus, differences in functional group abundance can be a strong driver of observed plant species richness patterns.     

Species richness of marine macrophytes is correlated to a wave exposure gradient

Wave exposure is one of the fundamental variables of the coastal environment and many coastal processes are affected by waves and wave‐induced water motion. Directly or indirectly, waves affect the lives of many coastal macroalgae and seagrasses. Although the idea that waves can affect macrophyte distribution and biodiversity is not new, it remains poorly examined. We looked at how a gradient of wave exposure, determined using the surf similarity number, influences the species richness of macrophytes among phyla and functional form groups. We suggest that wave exposure is a biologically and statistically significant variable and that the species richness of most phyla and groups decrease with increasing exposure. More interestingly, the analysis suggests that the Phaeophyta and the thick‐leathery functional form group, which are associated with important coastal habitats (i.e. submarine forests), increases in species richness as exposure increases. It appears that the effect of wave exposure varies with phyla and functional form group. Consequently, we reinforce the belief that studies that address the biodiversity and distribution of macrophytes must include wave exposure as a measured variable, to provide any meaningful synthesis of the ecology of these organisms.     

Prediction of neotropical tree and liana species richness from soil and climatic data

We present an analysis of local species richness in neotropical forests, based on a number of 0.1 ha samples of woody plants collected by the late Alwyn Gentry. For each of 69 forests, soils were analysed and climatic data were collated. Using transformed independent variables and interaction terms, multiple regression equations were developed that explained the greatest possible amount of variation in species richness, and the best equations were selected on the basis of regression diagnostics. The best models are presented for (a) all neotropical forests, (b) forests west of the Andes (transandean) and (c) east of the Andes (cisandean), and for various subsets based on elevation and annual rainfall. For the whole dataset, and for most subsets, annual rainfall and rainfall seasonality were the most important variables for explaining species richness. Soil variables were correlated with precipitation — drier forests have more nutrient-rich soils. After the inclusion of rainfall variables, available soil nutrient concentrations contributed little to explaining or accounting for additional variation in species numbers, indicating that tropical forest species richness is surprisingly independent of soil quality. The results are consistent with the hypothesis that plants in mature tropical forests may obtain nutrients through the process of direct cycling, in which mineral nutrients are extracted from litterfall before they enter the soil. The strong relationship between community species richness and rainfall patterns has implications for biodiversity conservation. Wet forests with an ample year-round moisture supply harbour the greatest number of woody plant species and should be a focus of conservation efforts.Died 3 August 1993.     

Anthropogenic noise reduces bird species richness and diversity in urban parks

Anthropogenic noise is becoming more prevalent in the world and has been shown to affect many animal species, including birds. The impact of such noise was measured in Neotropical urban parks to assess how the noise affects avifauna diversity and species richness. We sampled bird species, and concurrently measured sound pressure (noise) levels (L_eq, equivalent noise levels) in eight urban green areas or parks located in a large city (Belo Horizonte) in south‐eastern Brazil over a 1‐year period. The diversity of sampled points was measured by means of total species richness, Fisher's alpha and Shannon–Wiener diversity indices. Noise levels within all parks were greater than those in natural areas. We found that an increase in noise levels and the area of open habitats surrounding sampling points were negatively related to species richness. Social factors reflecting increased urbanization, such as higher incomes, were also negatively correlated with bird species richness. However, noise was the factor that explained most of the variance. These results suggest that anthropogenic noise can have a significant negative impact on the conservation value of urban parks for bird species.     

Genotypic richness and dissimilarity opposingly affect ecosystem functioning

Biodiversity is an essential determinant of ecosystem functioning. Numerous studies described positive effects of diversity on the functioning of communities arising from complementary resource use and facilitation. However, high biodiversity may also increase competitive interactions, fostering antagonism and negatively affecting community performance. Using experimental bacterial communities we differentiated diversity effects based on genotypic richness and dissimilarity. We show that these diversity characteristics have opposite effects on ecosystem functioning. Genotypic dissimilarity governed complementary resource use, improving ecosystem functioning in complex resource environments. Contrastingly, genotypic richness drove allelopathic interactions, mostly reducing ecosystem functioning. The net biodiversity effect on community performance resulted from the interplay between the genetic structure of the community and resource complexity. These results demonstrate that increasing richness, without concomitantly increasing dissimilarity, can decrease ecosystem functioning in simple environments due to antagonistic interactions, an effect insufficiently considered so far in mechanistic models of the biodiversity-ecosystem functioning relationship.     

Floral species richness,structural diversity and conservation value of vanilla agroecosystems in Madagascar

Agricultural landscapes provide financial livelihoods for farming communities in rural areas. However, such agroenvironments can significantly impact the local floral biodiversity and introduce harmful invasive species to the ecosystem. Despite the prominence of plantations throughout the tropics, their effects on local flora are limited to only a few specific cash crops and geographical regions. Here, we compared the species richness and structural diversity of vegetation in natural forest fragments and three types of vanilla plantation within the Sava region of north-east Madagascar ranging from those within or adjacent to existing forests, to intensively cultivated plantations. We recorded data on plant species abundance, diameter at breast height and canopy cover within multiple sites of each habitat. We used abundance data to calculate species richness indices, and we compared these metrics between habitats. Forested habitats contained a significantly higher floral species richness, structural diversity and more endemic and regionally native species than nonforested, anthropogenic vanilla plantations. However, our results suggest that the high floral species richness and structural diversity of natural forests can be partially achieved in vanilla plantations, depending on the site's management regime; traditionally managed vanilla plantations located close to natural forests can support diverse floral communities. These encouraging findings for plant conservation and sustainable agroforestry in Madagascar suggest that that newly created vanilla plantations and already existing nonforested plantations should endeavour to follow the more traditional forested approach to enhance the future sustainability and promote floristic diversity.     

喀斯特常绿落叶阔叶混交林物种多度与丰富度空间分布的尺度效应

物种多样性的空间分布格局及其尺度效应是生态学研究的重点,对于理解物种多样性的形成和维持机制以及生物多样性的管理和保护均具有重要意义。以贵州茂兰国家级自然保护区分布的亚热带原生性喀斯特常绿落叶阔叶混交林为研究对象,分析了2个1hm2(100m×100m)样地中物种多度和丰富度的空间分布特征及其与取样尺度的关系,采用方差和变异系数描述多度和丰富度在5个尺度(5m×5m,10m×10m,20m×20m,25m×25m,50m×50m)上的空间变异性。结果表明:(1)两个样地的物种多度和丰富度具有尺度依赖性特征;(2)由于多度具有叠加性,物种多度的方差随着尺度的增加呈线性增加,而变异系数呈线性下降;(3)丰富度的方差随尺度的增加表现出单峰分布的特征,在25 m×25 m尺度上达到最大值,变异系数则随取样尺度的增加而呈线性下降。研究表明,物种多度具有尺度推演规律,而丰富度却没有,因此,应慎重进行物种丰富度的尺度推演。在分析喀斯特森林物种多样性时,应注重尺度效应带来的影响。     

An exploration of factors influencing lotic insect species richness

An understanding of factors that influence species richness of lotic insects is generally lacking. We present comparative data on aquatic insect species richness from several North American and other streams. Factors such as large sample numbers and drainage area (species area relationships) are not significant predictors of species richness across the streams we examined. We explore several hypotheses regarding the origins and maintenance of species richness using Upper Three Runs Creek (UTR), South Carolina, USA, as a reference stream. UTR has the highest species richness of any stream in the Western Hemisphere. Hypotheses examined included historical, regional and local processes such as: (1) Evolutionary time, (2) disturbance regime/environmental variability, (3) temperature/evolutionary-speed, (4) productivity, and (5) habitat heterogeneity. Of these hypotheses, we suggest that productivity and habitat heterogeneity appear to contribute most to the high species richness found in UTR. We believe that multidisciplinary analysis of other streams is necessary because without this crucial information our knowledge of, and desire to protect biodiversity in streams will be wanting.     

A central Amazonian terra firme forest. I. High tree species richness on poor soils

Tree size, density, and species richness were established for three one-hectare plots of terra firme forest in central Amazonian Brazil. In the three hectares, 1916 individual trees with DBH 10 cm were sampled. A total of 58 families, 181 genera, and 513 species were determined. Hectare A had 285 species, 138 genera, and 47 families; hectare B 280 species, 123 genera, and 48 families; and hectare C 280 species, 125 genera, and 44 families. Comparably high species richness in Amazonia has heretofore only been reported from western Amazonia. This dispels the idea that high species richness can only develop in areas with rich soils and relatively high rainfall. It is suggested that such high species richness is the result of a combination of habitat heterogeneity and geological history. These high diversity forests, because they occur on nutrient poor soils, can be protected with little or no impact on development in the region because the soils are essentially useless for agriculture and for supporting long-term cattle pasture.     

Mammalian species richness and morphological complexity along an elevational gradient in the arid south-west

Aim We examined the relationship between species richness and morphological complexity of terrestrial mammal communities along an elevational gradient. Location The gradient is in the Sonoran Desert in Southern California and extends from a sand dune habitat near sea level to coniferous forest ending at >2600 m. Methods Morphological diversity, characterized by both size and shape of coexisting mammal species, was estimated within and between sites from projections of variables on principal components axes. Similarities among species were calculated as Euclidean distances. To tease apart size and shape, we constructed two principal component analyses: one based on log-transformed original measurements, the other on log-transformed proportional shape variables. To test whether species number accounted for the morphological diversity at each site we designed two null models. The models generated were random communities generated from the forty-two-species pool. Indices of morphological diversity for real communities were compared with the results of 500 simulations of each null model. Results Species richness varied along the gradient, peaking in the mid-elevation agave-ocotillo habitat. Morphological diversity of shapes and sizes correlated strongly with species richness. Locomotor, tooth, and skull traits were all important in distinguishing among species. Main conclusions Two important patterns emerged: (1) diversity of both sizes and of shapes of species within communities correlated positively with species number, and both sets of variables behaved similarly across this gradient; (2) the most species rich sites were not composed of specialists on these best places, but rather, a community of species derived from overlapping faunal groups.     

Environmental correlates of vegetation patterns and species richness in the northern Grampians,Victoria

Abstract Plant species cover-abundance and density data were collected for 94 sample plots across a gradient from rocky uplands to sandy outwash plains in the northern part of Grampians (Gariwerd) National Park in western Victoria. Detrended correspondence analysis (DCA) was used to identify dominant gradients in species composition. A range of static (e.g. substrate type, soil depth, microclimate indicators) and dynamic (e.g. elapsed time since last fire) environmental variables were measured. Correlations were sought between these variables and vegetation patterns including those for richness (R) and Shannon-Weiner diversity (H′). The dominant gradient of vegetation change identified by DCA separated rocky sites and sites near ephemeral streams, from well-drained, sandy sites. Secondary gradients identified time since last fire as important for sandy sites, and altitude and aspect-related microclimate for rocky sites. Diversity was highest in the first 2 years after fire but showed no further decline in older sites. Overall, R and H' were negatively correlated with soil nutrient concentrations. On sandy sites R was high, but was low on rocky sites and near streams. Within the rocky sites, R was highest on cool, moist south and east slopes, and lowest on hot, dry north and west slopes. Explanations of diversity patterns based on inhibition of competitive exclusion due to stress and recurrent disturbance best fit the results presented here.     

Spatial and environmental determinants of vascular plant species richness distribution in the Iberian Peninsula and Balearic Islands

Using an exhaustive data compilation, Iberian vascular plant species richness in 50 times 50 UTM grid cells was regressed against 24 explanatory variables (spatial, geographical, topographical, geological, climatic, land use and environmental diversity variables) using Generalized Linear Models and partial regression analysis in order to ascertain the relative contribution of primary, heterogeneous and spatially structured variables. The species richness variation accounted for by these variables is reasonably high (65% of total deviance). Little less than half of this variation is accounted for spatially structured variables. A purely spatial component of variation is hardly significant. The most significant variables are those related to altitude, and particularly maximum altitude, whose cubic response reflects the occurrence of the maximum number of species at the highest altitudes. This result highlighted the importance of Iberian mountains as hotspots of diversity and the relevance of large and small scale historical factors in contemporary plant distribution patterns. Climatic or energy-related variables contributed little, whereas geological (calcareous and acid rocks) and, to a lesser extent, environmental heterogeneity variables (land use diversity and altitude range) seem to be more important.