Spatial Patterns Of Species Diversity Research Articles

A long-ignored unique ecosystem of cavefishes in the southern karst: achievements, challenges, and prospects.

Cavefishes represent a taxon that has experienced natural selection pressures. This paper summarizes the results with respect to the taxonomy, diversity, phylogeny, and adaptation aspects of cavefishes research. It showed that: 1) These studies suggest that cavefishes play important roles in the study of geologic history and adaptation to extreme environments, but the mechanisms involved 168 species of cavefishes belonging to 17 genera, four families, and two orders have been recorded in China. Meanwhile, more new species are being discovered recently, and the species diversity of cavefishes are still underestimated, indicating the need to strengthen the survey in field. 2) The biogeography of cavefishes have focused on Sinocyclocheilus and Triplophysa, that have helped understand the geomorphology of karst areas in southern China and the spatial pattern of species diversity. These studies revealed the influences of evolution and geological history in Sinocyclocheilus, but there are still many species that have not been studied accordingly. 3) Some adaptive mechanistic studies have been conducted on cavefishes, primarily focusing on eye and body color degradation and energy metabolism in the genus Sinocyclocheilus to reveal adaptive mechanisms in the dark environment. 4) The IUCN list of protected cavefishes species in China only includes 21 species. The List of Key Protected Wild Animals for 2021 includes all species of Sinocyclocheilus as National Class II.It is necessary to strengthen the research on the biodiversity and adaptation and need consider the conservation actions for cavefishes.

Spatial Patterns of Species Diversity of Amphibians in a Nature Reserve in Eastern China

Elevational gradients provide an excellent opportunity to assess biodiversity patterns and community structure. Previous studies mainly focus on higher elevations or are limited to small areas in mountainous regions. Little information can be found on amphibian biodiversity in middle- and low-elevational areas, hence our study was devoted to filling up the current gaps in these research areas. To understand the variability of biodiversity of amphibian species in the Fujian Junzifeng National Nature Reserve in eastern China, our study included taxonomic and phylogenetic components to describe the various patterns of regional and elevational distribution. The results showed that (1) most of the taxonomic and phylogenetic diversity metrics were correlated; with regard to the surveyed area, Faith's phylogenetic diversity index (PD) and net relatedness index (NRI) were positively correlated with the Shannon-Wiener index (H'), Margalef index (DMG), and species richness (S), while negatively with the Pielou index; whereas for elevation, only the Pielou index was positively correlated with the nearest taxon index (NTI), but negatively with other indices; (2) taxonomic and phylogenetic diversities did not differ among the three survey locations but differed significantly along the elevational gradient; Simpson index, H', S, and DMG had a hump-shaped relationship with elevations, and PD decreased gradually with the increase in elevation, whereas NRI and NTI sharply increased at the elevation above 900 m; (3) the species range size and the corresponding midpoint of amphibians were affected by a strong phylogenetic signal, which supports the elevational Rapoport's rule upon removal of Pachytriton brevipes and Boulenophrys sanmingensis from the study.

Pollinators and urban riparian vegetation: important contributors to urban diversity conservation

BackgroundUrbanization process around the world has not only changed the patterns of land use, but also fragmented the habitat, resulting in significantly biodiversity loss. Urban rivers, serve as one of the natural corridors in urban ecosystems, are of importance for urban ecosystem stability. However, few studies have been done to explore the relationship between vegetation and pollinators in urban river segments. In this study, two urban streams in the city of Chongqing were selected as the study area, riparian vegetation, butterflies and bees were investigated along all four seasons of a year to illustrate the spatial and temporal distribution patterns. Simultaneously, the ecological functions of the river corridor were analyzed.ResultIn this study, 109 plant species belonging to 95 genera of 39 families were recorded; the number of sampled species for butterflies and bees were 12 and 13, respectively. The temporal and spatial patterns of species diversity among vegetation, butterfly, and bee are different, but the trends of variation among them are similar between the two streams. Bees were found to be more closely correlated with native flowering plants in riparian zone, rather than with cultivated riparian vegetation.ConclusionsThe native riparian vegetation in urban rivers plays an important role in urban biodiversity conservation by serving as a corridor. This study provides data supporting the protection of the remaining natural patches and restoration of damaged habitats in the city. The survey has accumulated data on native riparian vegetation and pollinators in urban rivers.

Areas of species diversity and endemicity of Nepal

AbstractIn this study, we analyzed the distribution and the spatial pattern of species diversity of vascular plants in Nepal. The aim was to identify and evaluate the occurrence and status of species‐rich areas in Nepal using ecological and environmental drivers. We used 52,973 georeferenced herbarium specimen records, representing 2650 species collected from Nepal. Altogether, 41 environmental variables were used for model development and validation. We used MaxEnt to predict the distribution pattern. All the significant species distribution predictions were then used to develop a species richness and endemism pattern in Nepal. The High Mountain and Himalaya, particularly east and central Nepal, were found to be species diverse and endemically rich areas, whereas western Nepal had lower species richness. We observed that isothermality, slope, rugosity, potential evapotranspiration, precipitation of humid months, temperature annual range, mean diurnal range, and normalized difference in vegetation index of humid months were the most influential environmental and climatic variables. We observed that about 60% of the areas, which had highest richness and endemism values, are still not included in protected areas in Nepal. We quantitatively analyzed the species richness and endemicity patterns of Nepal and were able to identify 19 areas of high species diversity and endemicity, six of which are newly identified.

Coastal Dune Vegetation Mapping Using a Multispectral Sensor Mounted on an UAS

Vegetation mapping, identifying the type and distribution of plant species, is important for analysing vegetation dynamics, quantifying spatial patterns of vegetation evolution, analysing the effects of environmental changes and predicting spatial patterns of species diversity. Such analysis can contribute to the development of targeted land management actions that maintain biodiversity and ecological functions. This paper presents a methodology for 3D vegetation mapping of a coastal dune complex using a multispectral camera mounted on an unmanned aerial system with particular reference to the Buckroney dune complex in Co. Wicklow, Ireland. Unmanned aerial systems (UAS), also known as unmanned aerial vehicles (UAV) or drones, have enabled high-resolution and high-accuracy ground-based data to be gathered quickly and easily on-site. The Sequoia multispectral sensor used in this study has green, red, red edge and near-infrared wavebands, and a regular camer with red, green and blue wavebands (RGB camera), to capture both visible and near-infrared (NIR) imagery of the land surface. The workflow of 3D vegetation mapping of the study site included establishing coordinated ground control points, planning the flight mission and camera parameters, acquiring the imagery, processing the image data and performing features classification. The data processing outcomes included an orthomosaic model, a 3D surface model and multispectral imagery of the study site, in the Irish Transverse Mercator (ITM) coordinate system. The planimetric resolution of the RGB sensor-based outcomes was 0.024 m while multispectral sensor-based outcomes had a planimetric resolution of 0.096 m. High-resolution vegetation mapping was successfully generated from these data processing outcomes. There were 235 sample areas (1 m × 1 m) used for the accuracy assessment of the classification of the vegetation mapping. Feature classification was conducted using nine different classification strategies to examine the efficiency of multispectral sensor data for vegetation and contiguous land cover mapping. The nine classification strategies included combinations of spectral bands and vegetation indices. Results show classification accuracies, based on the nine different classification strategies, ranging from 52% to 75%.

Multiscale spatial patterns of species diversity and biomass together with their correlations along geographical gradients in subalpine meadows

Researchers frequently discuss spatial distribution patterns of species diversity and biomass together with their correlations along geographical gradients. Typical subalpine meadows occur widely on the east of the Loess Plateau, China; here, we selected nine mountains belonging to four mountain systems from north to south on the east of the plateau. We analyzed five latitudinal and longitudinal gradients together with six elevational gradients to study the spatial distribution patterns of species diversity (including α, β, and γ diversity) and biomass plus with their relationships at various scales. Results showed that (1) for diversity, α-Diversity manifested unimodal variation patterns in horizontal spaces, peaking at high latitude and low longitude. However, α-diversity was not sensitive to elevation in vertical spaces and tended to decrease with increasing elevation. With increased latitude, longitude, and elevation, β-Diversity diminished; meanwhile, the rate of species turnover decreased and the similarity of community composition enlarged. γ-Diversity demonstrated quadratic function changes that were initially incremental and then decreased with increasing longitude, elevation, and latitude from 37.5° to 40°. In general, β-diversity had positive correlation with γ-diversity and negative correlation with α-diversity, which conformed to the function of β = γ/α. (2) For biomass, changes of aboveground biomass (AB) were more obvious along latitudinal gradients, whereas variations of belowground biomass (BB) had smaller differences along longitudinal and latitudinal gradients. More biomass was allocated to BB toward the north and east, whereas root-to-shoot ratio (R/S) was more evident at greater latitude than greater longitude. With increased elevation, more biomass was also allocated to BB, and the relationship of biomass to elevation was closer in AB. In short, the relation of biomass allocation tended to belowground plant parts with different geographical scales. (3) Species diversity had the strongest positive influence on AB. The Patrick and Shannon indices had correlations of power functions with AB and R/S, respectively, indicating that an allometric model could be used to model relationships between species diversity and biomass. In conclusion, the unique geomorphological structures with a series of basins between mountain systems on the east of the Loess Plateau, meant that subalpine meadows were mostly distributed along latitudinal directions, so the spatial distribution of species diversity and biomass was more evident along latitudinal gradients, and thus the response of aboveground biomass was more sensitive to variations of spatial gradients and species diversity.

VEGETATION MAPPING OF A COASTAL DUNE COMPLEX USING MULTISPECTRAL IMAGERY ACQUIRED FROM AN UNMANNED AERIAL SYSTEM

Abstract. Vegetation mapping, identifying the distribution of plant species, is important for analysing vegetation dynamics, quantifying spatial patterns of vegetation evolution, analysing the effects of environment changes on vegetation, and predicting spatial patterns of species diversity. Such analysis can contribute to the development of targeted land management actions that maintain biodiversity and ecological functions. This paper represents a methodology for 3D vegetation mapping of a coastal dune complex using a multispectral camera mounted on an Unmanned Aerial System (UAS) with particular reference to the Buckroney dune complex in Co. Wicklow, Ireland. UAS, also known as Unmanned Aerial Vehicles (UAV’s) or drones, have enabled high-resolution and high-accuracy ground-based data to be gathered quickly and easily on-site. The Sequoia multispectral camera used in this study has green, red, red-edge and near infrared wavebands, and a normal RGB camera, to capture both visible and NIR images of the land surface. The workflow of 3D vegetation mapping of the study site included establishing ground control points, planning the flight mission and camera parameters, acquiring the imagery, processing the image data and performing features classification. The data processing outcomes include an orthomosiac model, a 3D surface model and multispectral images of the study site, in the Irish Transverse Mercator coordinate system, with a planimetric resolution of 0.024 m and a georeferenced Root-Mean-Square (RMS) error of 0.111 m. There were 235 sample area (1 m × 1 m) used for the accuracy assessment of the classification of the vegetation mapping. Feature classification was conducted using three different classification strategies to examine the efficiency of multispectral sensor data for vegetation mapping. Vegetation type classification accuracies ranged from 60 % to 70 %. This research illustrates the efficiency of data collection at Buckroney dune complex and the high-accuracy and high-resolution of the vegetation mapping of the site using a multispectral sensor mounted on UAS.

Effects of neutrality and productivity on mammal richness and evolutionary history in Australia

Explaining how heterogeneous spatial patterns of species diversity emerge is one of the most fascinating questions of biogeography. One of the great challenges is revealing the mechanistic effect of environmental variables on diversity. Correlative analyses indicate that productivity is associated with taxonomic, phylogenetic, and functional diversity of communities. Surprisingly, no unifying body of theory have been developed to understand the mechanism by which spatial variation of productivity affects the fundamental processes of biodiversity. Based on widely discussed verbal models in ecology about the effect of productivity on species diversity, we developed a spatially explicit neutral model that incorporates the effect of primary productivity on community size and confronted our model's predictions with observed patterns of species richness and evolutionary history of Australian terrestrial mammals. The imposed restrictions on community size create larger populations in areas of high productivity, which increases community turnover and local speciation, and reduces extinction. The effect of productivity on community size modeled in our study causes higher accumulation of species diversity in productive regions even in the absence of niche‐based processes. However, such a simple model is not capable of reproducing spatial patterns of mammal evolutionary history in Australia, implying that more complex evolutionary mechanisms are involved. Our study demonstrates that the overall patterns of species richness can be directly explained by changes in community sizes along productivity gradients, supporting a major role of processes associated with energetic constraints in shaping diversity patterns.

Using functional trait diversity patterns to disentangle the scale‐dependent ecological processes in a subtropical forest

Abstract Disentangling ecological processes that influence community assembly and species diversity across spatial scales remains a major goal of community ecology. Community assembly processes influence spatial patterns of species diversity through their interactions with key functional traits. Hence, quantifying spatial patterns of functional trait diversity (FD) represents a useful tool for disentangling the relative importance of abiotic filtering, biotic interactions, random assembly and dispersal limitation across spatial scales. Here, we measured 12 traits of 112 study species in a 20‐ha fully mapped subtropical forest plot. The individuals of the 112 study species account for 99% of all living stems with diameter at breast height ≥ 1 cm. We studied important functional traits related to physiological processes of plants including resource acquisition (e.g. CO2 assimilation rate and leaf nutrient concentration) and drought tolerance (e.g. stem hydraulic conductivity and leaf turgor loss point). Additionally, species abundance, spatial locations (x‐ and y‐coordinates for each individual of the 112 study species) as well as topographic and soil variables that represent potentially important attributes of the physical environment of the plot were also included in our dataset. We employed two FD‐based tests (comparing FD within communities to those from random communities, distance‐based Moran's eigenvector maps (MEM) and redundancy analysis‐based variance partitioning), and one spatial analysis (inhomogeneous bivariate pair correlation analysis) to quantify the spatial patterns of FD of the plot at multiple spatial scales (400, 900, 1,600, 2,500 and 10,000 m2). We demonstrate that abiotic filtering is the major determinant responsible for trait convergence at relatively small scales (400, 900 and 1,600 m2), whereas dispersal limitation becomes dominant, causing the weakening of trait convergence at relatively large scales (2,500 and 10,000 m2). Our results highlight the relative contributions of different ecological processes to community assembly at different spatial scales, which can be distinguished using the diversity patterns of key functional traits. Also, our integrated approaches constitute a useful study design to disentangle variable ecological processes in shaping community assembly across spatial scales. A plain language summary is available for this article.

Spatial patterns of species diversity in sand dune plant communities in Yucatan, Mexico: importance of invasive species for species dominance patterns

Background: Coastal ecosystems in Mexico remain understudied in spite of their ecological, economic and conservation value and are being impacted by human activities along the coast. Knowledge on spatial patterns of plant species distribution that helps preserve these fragile ecosystems is crucial.Aims: We evaluated differences in species richness, species diversity and species dominance patterns in 16 plant communities as well as the degree to which differences were driven by climatic conditions in sandy dunes in Yucatán. We evaluated the importance of invasive species in mediating patterns of species diversity and species dominance patterns.Results: We found wide variation in plant species richness, species diversity and species dominance patterns among communities that stems from broad climatic differences along dune systems. Invasive plants represent almost one-third of total species richness and seem to be drastically changing the species dominance patterns in these communities.Conclusions: Regional climatic differences along the Yucatán north coast seems to be a major driver of plant diversity and species composition. Our findings suggest that invasive plants have successfully colonised and spread along the coast over the past 30 years. Even though invasive species do not alter spatial patterns of species diversity, they are becoming more dominant with potential detrimental consequences for native plants.

桂西北喀斯特常绿落叶阔叶混交林物种多样性分布格局的尺度效应

PDF HTML阅读 XML下载 导出引用 引用提醒 桂西北喀斯特常绿落叶阔叶混交林物种多样性分布格局的尺度效应 DOI: 10.5846/stxb201709231713 作者: 作者单位: 中国科学院亚热带农业生态研究所,中国科学院亚热带农业生态研究所,中国科学院亚热带农业生态研究所,中国科学院亚热带农业生态研究所,中国科学院亚热带农业生态研究所,广西壮族自治区木论国家级自然保护区管理局,中国科学院亚热带农业生态研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划项目（2016YFC0502405）；广西重点研发计划项目（桂科AB16380255，桂科AB17129009）；国家自然科学基金项目（31770495）；广西特聘专家项目 Scale-dependent spatial patterns for species diversity in a karst evergreen and deciduous broad-leaved mixed forest of northwest Guangxi Author: Affiliation: Institute of Subtropical Agriculture Chinese Academy of Sciences,Institute of Subtropical Agriculture Chinese Academy of Sciences,Institute of Subtropical Agriculture Chinese Academy of Sciences,Institute of Subtropical Agriculture Chinese Academy of Sciences,Institute of Subtropical Agriculture Chinese Academy of Sciences,,Institute of Subtropical Agriculture Chinese Academy of Sciences Fund Project: Dthe National Key Research and Development Program ( 2016YFC0502405), the Guangxi Key Research and Development Program (AB17129009, AB16380255), the National Natural Science Foundation of China (31370485, 31370623, 31400412), and the Guangxi Program of Distinguished Expert 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:物种多样性的空间分布格局及其与尺度的关系研究对于了解群落物种多样性形成机制具有重要意义。为了探讨喀斯特地区物种多样性空间分布格局的尺度效应，以喀斯特常绿落叶阔叶混交林25 hm2样地的（胸径DBH≥1）木本植物为研究对象，分析了6个空间尺度（5 m×5 m，10 m×10 m，20 m×20 m，50 m×50 m，100 m×100 m，250 m×250 m）上的多度、物种丰富度、Shannon-Wiener指数、Simpson指数以及Pielou均匀度指数的变化规律。结果表明：物种多样性指数的空间分布均表现出较高的空间异质性；物种多样性指数的方差随取样尺度增加呈现单峰分布特征，并且在100 m×100 m尺度上达到最大值；物种多样性指数的变异系数随尺度的增加呈线性下降趋势，其中，Shannon-Wiener指数、Simpson指数以及Pielou均匀度指数均在5 m×5 m至20 m×20 m尺度上明显减小；在大于50 m×50 m的尺度上，物种丰富度与多度的正相关性不显著（P > 0.05）。喀斯特常绿落叶阔叶混交林物种多样性的空间分布格局与不同空间尺度密切相关，深入解析物种多样性随空间尺度的变化模式，需要在类似的森林生态系统做更多的研究。 Abstract:Spatial distribution patterns of species diversity and their relationships with scale are of great significance to understand the mechanism of community species diversity formation. Here, a field survey was conducted to assess the variation in species diversity along spatial scales in a karst evergreen and deciduous broad-leaved mixed forest, Southwest China. Based on the dataset of woody plants (DBH ≥ 1) from a 25 hm2 plot, the spatial distribution patterns of species abundance, species richness, and Shannon-Wiener, Simpson, and Pielou's evenness indices were analyzed at six spatial scales-5 m×5 m, 10 m×10 m, 20 m×20 m, 50 m×50 m, 100 m×100 m, and 250 m×250 m. The results showed that spatial distributions of species diversity indices were highly heterogeneous. The variance of species diversity indices changed with spatial scale following a unimodal pattern, i.e., with a maximum value at the 100 m×100 m scale. Variation coefficients of species diversity decreased linearly with increasing scale. The Shannon-Wiener, Simpson, and Pielou's evenness indices decreased sharply at the 5 m×5 m and 20 m×20 m scales. No significant positive relationship was found between species richness and abundance at scales over 50 m×50 m (P > 0.05). Our results suggest that the spatial pattern of species diversity in this evergreen and deciduous broad-leaved mixed karst forest is closely related to spatial scale. To better understand spatial variation of species diversity across spatial scales, more such studies in other similar forest ecosystems are needed. 参考文献 相似文献 引证文献

Spatial Patterns of Species Diversity and Phylogenetic Structure of Plant Communities in the Tianshan Mountains, Arid Central Asia.

The Tianshan Mountains, located in arid Central Asia, have a humid climate and are biodiversity hotspots. Here, we aimed to clarify whether the pattern of species diversity and the phylogenetic structure of plant communities is affected by environmental variables and glacial refugia. In this study, plant community assemblies of 17 research sites with a total of 35 sample plots were investigated at the grassland/woodland boundaries on the Tianshan Mountains. Community phylogeny of these plant communities was constructed based on two plant DNA barcode regions. The indices of phylogenetic diversity and phylogenetic community structure were calculated for these sample plots. We first estimated the correlation coefficients between species richness (SR) and environmental variables as well as the presence of glacial refugia. We then mapped the significant values of indices of community phylogeny (PD, RPD, NRI, and NTI) to investigate the correlation between community phylogeny and environmental structure or macrozones in the study area. The results showed that a significantly higher value of SR was obtained for the refugial groups than for the colonizing groups (P < 0.05); presence of refugia and environmental variables were highly correlated to the pattern of variation in SR. Indices of community phylogeny were not significantly different between refugial and colonizing regions. Comparison with the humid western part showed that plant communities in the arid eastern part of the Tianshan Mountains tended to display more significant phylogenetic overdispersion. The variation tendency of the PhyloSor index showed that the increase in macro-geographical and environmental distance did not influence obvious phylogenetic dissimilarities between different sample plots. In conclusion, glacial refugia and environmental factors profoundly influenced the pattern of SR, but community phylogenetic structure was not affected by glacial refugia among different plant communities on the Tianshan Mountains. This pattern of community phylogenetic structure could have resulted from shared ancestry and species pool among these sample plots.

Functional dependence underlies a positive plant-grasshopper richness relationship

A central focus of ecology is identifying the factors that shape spatial patterns of species diversity and this is particularly relevant in an era of global change. Positive relationships between plant and consumer diversity are common, but could be driven by direct responses of each trophic level to underlying environmental gradients, or indirectly where changes in environmental conditions propagate through food webs. Here we use structural equation modeling to examine the relative importance of soil resource availability and disturbance (fire) in mediating relationships between plant and grasshopper richness in insular grasslands. We found a positive relationship between plant and consumer richness that became stronger after accounting for disturbance, despite unique responses of plants and consumers to the two environmental gradients. Plant richness responded to an underlying gradient in soil resource availability. Time since the last fire had a direct positive effect on grasshopper richness but had no effect on plant richness. This work supports that plant and consumer richness are functionally linked, rather than having similar responses to environmental gradients. By disentangling the direct and indirect processes underlying a positive relationship between plant and consumer diversity in a natural system that spans multiple environmental gradients, we demonstrate the importance of investigating biodiversity through explicit multivariate models.

小秦岭自然保护区苔藓植物群落数量分类、排序及多样性垂直格局

PDF HTML阅读 XML下载 导出引用 引用提醒 小秦岭自然保护区苔藓植物群落数量分类、排序及多样性垂直格局 DOI: 10.5846/stxb201512242568 作者: 作者单位: 河南农业大学,河南农业大学,河南农业大学,河南农业大学,河南小秦岭国家级自然保护区管理局,河南农业大学,河南农业大学 作者简介: 通讯作者: 中图分类号: 基金项目: 河南省科技攻关（132102110133）；河南省教育厅科学技术研究重点项目（14A180013） Numerical classification, ordination, and species diversity of bryophytes along elevation gradients in Xiaoqinling Author: Affiliation: Henan Agricultural University,Henan Agricultural University,Henan Agricultural University,Henan Agricultural University,Administration Bureau of Xiaoqinling National Nature Reserve of Henan,Henan Agricultural University,Henan Agricultural University Fund Project: 河南省科技攻关（１３２１０２１１０１３３）；河南省教育厅科学技术研究重点项目（１４Ａ１８００１３） 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:苔藓物种多样性沿海拔梯度呈什么样的分布格局?基于53个20 m×20 m样地，采集并鉴定了样地内所有生境中的苔藓物种；采用多元回归树（multivariate regression trees， MRT）对苔藓植物进行分类；采用典范对应分析（canonical correspondence analysis， CCA）进行排序分析；用广义线性模型（Generalized Linear Model， GLM）研究苔藓物种多样性沿海拔的分布格局。结果如下：（1）采集的1378份苔藓植物标本经过鉴定，共有33科89属240种，其中藓类226种，苔类14种；（2）经交叉验证认为本区苔藓植物可分为4类，Ⅰ长肋青藓（Brachythecium populeum）+大叶匐灯藓（Plagiomnium succulentum）+圆叶匐灯藓（Plagiomnium vesicatum）群落，Ⅱ灰白青藓（Brachythecium albicans）+宽叶青藓（Brachythecium curtum）+短肋羽藓（Thuidium kanedae）+平肋提灯藓（Mnium laevinerve）群落，Ⅲ短肋羽藓（Thuidium kanedae）+光萼叶苔（Jungermannia leiantha）+薄罗藓（Leskea polycarpa）+叉肋藓（Trachyphyllum inflexum）群落，Ⅳ宽叶青藓（Brachythecium curtum）+垂蒴棉藓（Plagiothecium nemorale）+全缘匐灯藓（Plagiomnium integrum）群落；（3）海拔、坡度和坡向对苔藓物种分布的解释量为7.29%；（4）苔藓物种多样性随海拔的变化成明显的上升格局。通过研究了解了小秦岭国家级自然保护区苔藓物种组成、群丛划分以及每种苔藓植物的海拔分布范围；苔藓物种多样性随海拔的上升呈显著的上升格局，与乔木、灌木和草本的分布格局不同。希望此研究能为苔藓植物生态学研究和物种多样性保护提供参考。 Abstract:Bryophytes are widely distributed and constitute an important part in vegetation diversity. More than 20,000 species of bryophytes are found worldwide. Bryophytes play important roles in the ecosystem, particularly in water balance and nutrient accumulation. However, bryophytes are smaller than vascular plants and are often ignored in ecological studies. Spatial patterns of species diversity along the elevation gradient are of great significance in illuminating community ecology. What is the distribution pattern of bryophyte species diversity along an elevation gradient? We do not find the related research in China. The Xiaoqinling National Nature Reserve is located in Lingbao (34°23'-34°31'N, 110°23'-110°44'E, Henan Province, China). This nature reserve covers 31 km from east to west and 12 km from north to south, and spreads over a total area of 15,160 km2. The reserve harbors the highest peak in Henan, with an elevation of 2413.8 m. The area has rich biological resources with a diverse and complex vegetation composition. We constructed 53 plots in a 400m2 area (20 m×20 m) along the altitudinal gradient in Xiaoqinling, collected all bryophyte species encountered in these 53 plots, and recorded habitat types such as ground, tree trunks, roots, and rotten wood. Investigators carefully checked every corner of each plot to collect all bryophyte species growing on the plot. A total of 1378 specimens were collected. All specimens were transported back to the laboratory and identified. The bryophyte community was classified using multiple regression trees. Ordination analysis was conducted by canonical correspondence analysis, and the generalized linear model was used to study the distribution pattern of species diversity along elevation gradients. Results were as follows. (1) The collected 1378 bryophyte specimens belonged to 33 families, 89 genera, and 240 species, including 226 species of mosses and 14 species of liverworts. (2) The bryophyte community was divided into four categories by cross validation: I: Brachythecium populeum + Plagiomnium succulentum + Plagiomnium vesicatum; Ⅱ: Brachythecium albicans + Brachythecium curtum + Thuidium kanedae + Mnium laevinerve; Ⅲ: Thuidium kanedae + Jungermannia leiantha + Leskea polycarpa + Trachyphyllum inflexum; IV: Brachythecium curtum + Plagiothecium nemorale + Plagiomnium integrum. (3) The interpretation of the elevation, slope, and aspect to the distribution of the bryophyte species was 7.29%. (4) The bryophyte species diversity increased with the increase in altitude. In this study, we examined the species composition, classification, and distribution range along elevation gradients of the bryophyte species in Xiaoqinling. The diversity of the bryophyte species along the altitude showed an increasing tendency and differed from the distribution patterns of trees, shrubs, and herbs. Thus, this study provides a reference for research on bryophyte species coexistence and protection of species diversity. Vascular plants and bryophytes coexist in an ecosystem and the relationship between vascular plants and the bryophyte community is complex. However, we did not consider the effect of vascular plants on the bryophyte community and these factors need further analysis. Environmental factors, such as climatic conditions, physical and chemical properties of bark, and light intensity, must also be considered in future studies. 参考文献 相似文献 引证文献

High β‐diversity maintains regional diversity in Brazilian tropical coastal stream fish assemblages

AbstractUnderstanding spatial patterns of species diversity and the variables that structure biological communities is critical to successful ecosystem management. Regional diversity (γ) can be considered a combination of local diversity (α) and among sites variation (β). Using abundance data of fish species in 19 stream stretches, an analysis of diversity partitioning was used to determine the contribution of α‐ and β‐diversity to γ‐diversity. Redundancy analysis was applied to find the contribution of environmental variables and spatial configuration to species composition. Intersite variation contributed significantly to γ‐diversity. Spatial configuration and instream heterogeneity (coarse substrate, channel width, water velocity and shading) and riparian vegetation were related to local fish abundances. Conservation actions should consider that all streams are important, and prioritisation of just a small number of the richest sites is not appropriate.

Spatial patterns of species diversity in the herb layer of early post-fire regeneration in mixed Pinus yunnanensis forests

Spatial patterns of species diversity in the herb layer of early post-fire regeneration in mixed Pinus yunnanensis forests

Scale-dependent spatial patterns of species diversity in the tropical montane rain forest in Jianfengling, Hainan Island, China

Aims Spatial distribution patterns and formation mechanisms of species diversity are fundamental issues in community ecology. The objectives of this study are to assess the species diversity patterns at the different spatial scales in Jianfengling, Hainan Island, China. Methods Based on the dataset from the 60 hm plot in the tropical montane rain forest in Jianfengling, Hainan Island, the spatial distribution patterns of species richness, species abundance, Shannon-Wiener, Simpson and Pielou’s evenness indices were analyzed at six spatial scales, including 5 m × 5 m, 10 m × 10 m, 20 m × 20 m, 40 m × 40 m, 100 m × 100 m, and 200 m × 200 m, respectively. Important findings Results showed that spatial distribution patterns of species richness, species abundance and Shannon-Wiener index were much more obviously changed with the spatial scales than Simpson and Pielou’s evenness indices. Change of variance of the species richness with the increase of spatial scales was unimodal, which had the maximum value at the 20 m × 20 m scale. Variance of the species abundance showed a linear relationship with the increase of spatial scales. The positive relationship between species richness and abundance gradually decreased and even disappeared with the increase of sampling scales, which may be correlated with the increase of habitat heterogeneity. The effects of spatial scales on Shannon-Wiener, Simpson, and Pielou’s evenness indices may be also correlated with the composition of rare species in the plot.

AdsPackage forR: A Fast Unbiased Implementation of theK-function Family for Studying Spatial Point Patterns in Irregular-Shaped Sampling Windows

ads is an R package that performs multi-scale spatial point pattern analyses through methods derived from Ripley's K-function. These methods apply to univariate, multivariate or marked point data mapped in a rectangular, circular or irregular-shaped sampling window. Specific tests of statistical significance based on Monte Carlo simulations are associated to these methods. The main features of ads is to call fast C subroutines for computing Ripley's unbiased local correction of edge effects for various sampling window configurations and for performing Monte Carlo simulations. It thus allows one to analyze large datasets and to compute robust confidence envelopes. This paper is an introduction to ads version 1.5, focusing on its complementarity with the other R packages for spatial point pattern analysis, and on recent original developments towards the introduction of multivariate functions for analyzing spatial pattern of species diversity.

Node‐based analysis of species distributions

Summary The integration of species distributions and evolutionary relationships is one of the most rapidly moving research fields today and has led to considerable advances in our understanding of the processes underlying biogeographical patterns. Here, we develop a set of metrics, the specific overrepresentation score (SOS) and the geographic node divergence (GND) score, which together combine ecological and evolutionary patterns into a single framework and avoids many of the problems that characterize community phylogenetic methods in current use. This approach goes through each node in the phylogeny and compares the distributions of descendant clades to a null model. The method employs a balanced null model, is independent of phylogeny size, and allows an intuitive visualization of the results. We demonstrate how this novel implementation can be used to generate hypotheses for biogeographical patterns with case studies on two groups with well‐described biogeographical histories: a local‐scale community data set of hummingbirds in the North Andes, and a large‐scale data set of the distribution of all species of New World flycatchers. The node‐based analysis of these two groups generates a set of intuitively interpretable patterns that are consistent with current biogeographical knowledge. Importantly, the results are statistically tractable, opening many possibilities for their use in analyses of evolutionary, historical and spatial patterns of species diversity. The method is implemented as an upcoming R package nodiv, which makes it accessible and easy to use.

Effects of negative density dependence and habitat filtering on temporal variation in phylogenetic community structure of seedlings in a mid-subtropical forest

Negative density dependence and habitat filtering are important mechanisms to explain the coexistence of species and the biodiversity patterns of forest communities. Negative density dependence is assumed to enhance phylogenetic α diversity via negative interactions among individuals within a species or among closely related species via competition for similar resources and the sharing of similar pathogens and predators. In contrast, habitat filtering is hypothesized to reduce phylogenetic β diversity within a habitat by selecting for similar resident species that can tolerate the habitat and by eliminating other species. Previous studies focused mainly on testing these two hypotheses by analyzing the spatial patterns of species diversity. Only a handful of studies have examined the temporal variation in phylogenetic community structure. This study attempted to test these two mechanisms by analyzing the temporal variation in community phylogenetic diversity of seedlings (DBH<1 cm) in 342 quadrats (1 m×1 m) in a mid-subtropical forest in Gutianshan National Nature Reserve, Zhejiang Province, China. We found that the phylogenetic α diversity of seedling within habitats increased significantly from the year 2006 to 2007. In contrast, the phylogenetic β diversity of seedlings within habitats declined significantly over time. These results suggested that negative density dependence and habitat filtering jointly determined the phylogenetic diversity patterns of communities in this subtropical forest.