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1.
    
Quantify tree functional and phylogenetic richness and divergence at the global scale, and explore the drivers underpinning these biogeographic patterns.  相似文献   

2.
    
Quadricilia rotundata is a heterotrophic flagellate with four flagella. However, because this species has no clear morphological characteristics or molecular data affiliating it with any known group, Q. rotundata has been treated as a protist incertae sedis, for a long time. Here, we established a clonal culture of Q. rotundata and sequenced its 18S rDNA sequence. Molecular phylogenetic analysis successfully placed Q. rotundata in an environmental clade within Cercozoa, which contributes to expand the morphological and species diversity within Cercozoa. We also discuss morphological evolution within Cercozoa based on this finding.  相似文献   

3.
Measures of biodiversity encompass variation along several dimensions such as species richness (SR), phylogenetic diversity (PD) and functional/trait diversity (TD). At the global scale, it is widely recognized that SR and PD are strongly correlated, but the extent to which either tends to capture variation in TD is unclear. Here, we assess relationships among PD, SR and TD for a number of traits both across clades and regional assemblages of mammals. We also contrast results using two different measures of TD, trait variance and a new measure we refer to as trait bin filling (the number of orders of magnitude of variation that contain at least one species). When TD is defined as trait variance, PD is a much stronger correlate of TD than SR across clades, consistent with hypotheses about the conservation value of PD. However, when TD is defined as bin filling, PD and SR show similar correlations with TD across clades and space. We also investigate potential losses of SR, PD and TD if species that are currently threatened were to go extinct, and find that threatened PD is often a similar predictor of threatened TD as SR.  相似文献   

4.
甲真菌病患者分离真菌多样性分析   总被引:2,自引:0,他引:2  
为了探寻甲真菌病患者病甲部位的真菌多样性,以期对临床治疗提供参考,结合菌种培养的形态学研究和rDNA ITS序列分析的方法,对临床拟诊为甲真菌病患者的病甲分离培养菌株进行物种鉴定,并以丰富性指数(Ma)、多样性指数(H′)、均匀度指数(J)等指标分析指甲和趾甲分离真菌的多样性。2010年2月至9月在北京大学第三医院皮肤科的1 568例拟诊甲真菌病患者中,641例培养阳性,包括趾甲561例和指甲80例。检测到的皮肤癣菌占59.13%(其中红色毛癣菌为96.04%),酵母菌17.00%,其他真菌23.87%。分离自趾甲的Candida galli、Lewia infectoria和Paraconiothyrium hawaiiense,以及分离自指甲的Cyberlindnera jadinii确定为中国新记录种。趾甲分离菌的物种多样性指数H′、丰富度指数Ma和均匀度指数J均高于指甲分离菌。研究结果表明,该医院就诊甲真菌病患者可分离培养的真菌以皮肤癣菌的红色毛癣菌为主要物种,且趾甲分离菌的菌种多样性较指甲的更为明显。  相似文献   

5.
鸟类是理想的生物多样性指示类群。中国观鸟记录中心(以下简称“记录中心”)是目前中国最大的鸟类监测公众科学数据平台, 其记录覆盖94%的全国鸟种和94.3%的县级行政区。本研究基于公众科学数据, 参考《区域生物多样性评价标准》(HJ 623-2011)中的受胁物种丰富度指数, 构建了鸟类丰富度指数(RB_A)和珍稀濒危鸟类丰富度指数(RTB_A), 继而提出一种对区域鸟类多样性进行评价的新方法。本研究计算了自2014年起, 各省级、地级、县级行政区(不含市辖区)每年在记录中心的累积记录鸟种数对官方发布鸟种数的覆盖率和省级行政区记录的累积珍稀濒危鸟种数对官方发布数据的覆盖率, 并计算了自2018年起各级行政区每年的RB_ARTB_A, 以了解各地鸟类丰富度指数的逐年变化情况, 并分析记录中心数据集的发展趋势和两个指数的敏感性。分析结果表明, 记录中心数据对全国各级行政区的鸟种覆盖率自2014年起逐年增加, 在2023年分别有94.1%的省级、59.0%的地级和49.0%的县级行政区(不含市辖区)的鸟种覆盖率超过90%; 记录中心的累积珍稀濒危鸟种数据在省级行政区的覆盖率亦呈上升趋势, 但略低于所有鸟种覆盖率。自2020年起, 全国每年观测到的鸟种数量呈逐年增加趋势, 但其中部分省份每年观测到的鸟种总数在2022年出现下降。自2020年起, 各省级行政区的RB_ARTB_A整体呈现上升趋势。RB_A范围为0.50-0.96, RTB_A范围为0.45-0.98, 显示RTB_A更为敏感。本研究结果表明, RB_ARTB_A在本地用户提交记录数量充足的地区有较大的应用价值, 可作为生物多样性评价指标应用。RTB_A对于鸟类多样性的变化更为敏感, 更能体现在地鸟类保护状况。随着记录中心等公众科学平台的发展, 以RB_ARTB_A为代表的基于公众科学的评价指数在物种多样性评估和物种监测方面有巨大的应用潜力。  相似文献   

6.
    
Abstract How to maximize the conservation of biodiversity is critical for conservation planning, particularly given rapid habitat loss and global climatic change. The importance of preserving phylogenetic diversity has gained recognition due to its ability to identify some influences of evolutionary history on contemporary patterns of species assemblages that traditional taxonomic richness measures cannot identify. In this study, we evaluate the relationship between taxonomic richness and phylogenetic diversity of angiosperms at genus and species levels and explore the spatial pattern of the residuals of this relationship. We then incorporate data on historical biogeography to understand the process that shaped contemporary floristic assemblages in a global biodiversity hotspot, Yunnan Province, located in southwestern China. We identified a strong correlation between phylogenetic diversity residuals and the biogeographic affinity of the lineages in the extant Yunnan angiosperm flora. Phylogenetic diversity is well correlated with taxonomic richness at both genus and species levels between floras in Yunnan, where two diversity centers of phylogenetic diversity were identified (the northwestern center and the southern center). The northwestern center, with lower phylogenetic diversity than expected based on taxonomic richness, is rich in temperate‐affinity lineages and signifies an area of rapid speciation. The southern center, with higher phylogenetic diversity than predicted by taxonomic richness, contains a higher proportion of lineages with tropical affinity and seems to have experienced high immigration rates. Our results highlight that maximizing phylogenetic diversity with historical interpretation can provide valuable insights into the floristic assemblage of a region and better‐informed decisions can be made to ensure different stages of a region's evolutionary history are preserved.  相似文献   

7.
    

Aim

Large ‐ scale diversity patterns are generated by different but not mutually exclusive mechanisms. However, understanding of multiple facets of diversity and their determinants in the freshwater realm remains limited. Here, we characterized the geographical gradients, hotspots and spatial congruence of three facets of freshwater molluscan diversity and evaluated the relative importance of three different underlying mechanisms related to the energy, area/environmental heterogeneity and dispersal/historical hypotheses.

Location

China.

Methods

Species richness (SR), functional richness (FR) and taxonomic distinctness (TD, a proxy of phylogenetic diversity) were calculated for 212 drainage basins with a total of 313 molluscan species. Spatial congruence between the diversity facets was evaluated with Pearson correlation coefficient and overlap among hotspots. Multiple linear regression models and variation partitioning were used to assess the relative importance of different mechanisms.

Results

Hotspots of SR and FR were mainly concentrated in the Yangtze River and Huai River basins, while high TD values were patchily distributed across China. We found extremely low spatial congruence between TD and both SR and FR, while there was relatively high concordance between SR and FR. All diversity facets were best explained by the dispersal/historical hypothesis with strong unique effects, followed by the factors related to the energy hypothesis. The area/ environmental heterogeneity hypothesis was only weakly supported.

Main conclusions

We found a potentially strong influence of dispersal limitation and evolutionary history on the geographical diversity gradients of Chinese molluscs. This finding contrasts with the general finding that energy‐related factors are the strongest correlates of diversity patterns at large spatial scales. Moreover, our results do not support the idea that using any one diversity component as a surrogate of the others in developing conservation strategies. Instead, an integrative approach embracing multiple facets of diversity should be adopted in the conservation of freshwater biodiversity.
  相似文献   

8.
    
Mitochondrial genomes can be assembled readily from shotgun‐sequenced DNA mixtures of mass‐trapped arthropods (“mitochondrial metagenomics”), speeding up the taxonomic characterization. Bulk sequencing was conducted on some 800 individuals of Diptera obtained by canopy fogging of a single tree in Borneo dominated by small (<1.5 mm) individuals. Specimens were split into five body size classes for DNA extraction, to equalize read numbers across specimens and to study how body size, a key ecological trait, interacts with species and phylogenetic diversity. Genome assembly produced 304 orthologous mitochondrial contigs presumed to each represent a different species. The small‐bodied fraction was the by far most species‐rich (187 contigs). Identification of contigs was through phylogenetic analysis together with 56 reference mitogenomes, which placed most of the Bornean community into seven clades of small‐bodied species, indicating phylogenetic conservation of body size. Mapping of shotgun reads against the mitogenomes showed wide ranges of read abundances within each size class. Ranked read abundance plots were largely log‐linear, indicating a uniformly filled abundance spectrum, especially for small‐bodied species. Small‐bodied species differed greatly from other size classes in neutral metacommunity parameters, exhibiting greater levels of immigration, besides greater total community size. We suggest that the established uses of mitochondrial metagenomics for analysis of species and phylogenetic diversity can be extended to parameterize recent theories of community ecology and biodiversity, and by focusing on the number mitochondria, rather than individuals, a new theoretical framework for analysis of mitochondrial abundance spectra can be developed that incorporates metabolic activity approximated by the count of mitochondria.  相似文献   

9.
  总被引:1,自引:0,他引:1  
  相似文献   

10.
    
Mountains have been recognized as biodiversity hotspots and possess strong elevational gradients. Whether these gradients exhibit similar characteristics in the multidimensional diversity patterns across different mountain ranges is a subject of inquiry. Exploring the elevational patterns of the diversity and phylogenetic information of plant species in the different subtropical mountains is necessary. Here, we compiled the elevational patterns of plant diversity occurring in the eight subtropical mountains of China and focused on the assessment of the patterns and determinants of the multi-dimensional diversity and phylogenetic structure in different mountains. We also detected the elevational patterns and their relationship between different groups. The results indicate two main patterns of multi-dimensional diversity: monotonic decrease and hump-shaped, along with the area effect on the species diversity. There is a strong positive link between the non-native and native species of species richness, and significant differences in phylogenetic structure's elevational distribution. We did not find the same rule in the mountains that the plant species in the lowlands indicate phylogenetic overdispersion, and the species in the higher elevation regions indicate phylogenetic clustering. We found that the plants' diversity peak is related to the mountains size, and this result showed that we should pay more attention to the conservation of plant communities in the higher elevation regions for the higher mountains. This study suggested that we should take different protective measures for the subtropical mountains: the lowland regions should be paid more attention in Mt. Lushan (LS), Mt. Guanshan (GS), Mt. Huanggang (HG), and Mt. Fanjing (FJ), and the middle-altitude regions should be of concern for other mountains. This study helps to better understand the elevational gradients of species diversity on different scales and provides supporting scientific basis for biodiversity conservation in the subtropical mountain regions.  相似文献   

11.
12.
    
A new species of Brachychalcinus is described from the Rio Trombetas basin, Brazil. It differs from congeners by possessing a conspicuous rounded second humeral spot. Additionally, our new species differs from Brachychalcinus nummus, B. orbicularis and B. reisi by having a higher number of branched dorsal-fin rays, and from Brachychalcinus parnaibae by having a lower head depth.  相似文献   

13.
    
Geospatial patterns in the distribution of regional biodiversity reflect the composite processes that underpin evolution: speciation, dispersal and extinction. The spatial distribution and phylogeny of a globally widespread and species rich bird family (Rallidae) were used to help assess the role of large‐scale biogeographical processes in diversity and diversification. Here, we examine how different geostatistical diversity metrics enhance our understanding of species distribution by linking occurrence records of rail species to corresponding species level phylogeny. Tropical regions and temperate zones contained a large proportion of rail species richness and phylogenetic diversity whilst small islands in Australian, Oceanian and Oriental regions held the highest weighted and phylogenetic endemism. Our results suggest that habitat connectivity and dispersal were important ecological features in rail evolution and distribution. Spatial isolation was a significant driver of diversification where islands in Oceania were centres of neo‐endemism with recent multiple and independent speciation events and could be considered as nurseries of biodiversity. Palaeo‐endemism was mostly associated with older stable regions, so despite extensive long distance range shifting these areas retain their own ancient and distinct character. Madagascar was the major area of palaeo‐endemism associated with the oldest rail lineages and could be considered a museum of rail diversity. This implies a mixture of processes determine the current distribution and diversity of rail clades with some areas dominated by recent ‘in situ’ speciation while others harbour old diversity with ecological traits that have stood the test of time.  相似文献   

14.
生物多样性与生态系统功能:进展与争论   总被引:50,自引:4,他引:50  
生物多样性与生态系统功能的关系已成为当前人类社会面临的一个重大科学问题,生物多样性的空前丧失,促使人们开展了大量研究工作来描述物种多样性-生态系统功能关系,并试图揭示多样性与系统功能关系的内在机制,本文将多样性对生态系统功能作用机制的有关假说分为统计学与生物学两大类:前者是从统计学角度来解释观察到的多样性-系统功能模式,包括抽样效应,统计均衡效应等;而后者是基于多样性的生物学效应给出的,包括生态位互补,种间正相互作用,保险效应等,本文较为详细地介绍了该领域内有代表性的实验工作,包括“生态箱”实验,Cedar Creek草地多样性实验,微宇宙实验,欧洲草地实验,以及在这些实验结果解释上的激烈争论。  相似文献   

15.
Ancestor–descendant relationships (ADRs), involving descent with modification, are the fundamental concept in evolution, but are usually difficult to recognize. We examined the cladistic relationship between the only reported fossil pygmy right whale, †Miocaperea pulchra, and its sole living relative, the enigmatic pygmy right whale Caperea marginata, the latter represented by both adult and juvenile specimens. †Miocaperea is phylogenetically bracketed between juvenile and adult Caperea marginata in morphologically based analyses, thus suggesting a possible ADR—the first so far identified within baleen whales (Cetacea: Mysticeti). The †Miocaperea–Caperea lineage may show long-term morphological stasis and, in turn, punctuated equilibrium.  相似文献   

16.
    

Aim

We used an eco-phylogenetic approach to investigate the diversity and assembly patterns of tropical dry forests (TDFs) in Central India. We aimed at informing conservation and restoration practices in these anthropogenically disturbed forests by identifying potential habitats of conservation significance and elements of regional biodiversity most vulnerable to human impact and climate change.

Location

Tropical dry forests of Madhya Pradesh, Central India.

Methods

We analysed the species richness, stem density, basal area and phylogenetic structure (standardized effect size of MNTD, MPD, PD and community evolutionary distinctiveness cED) of 117 tree species assemblages distributed across a ~230 to ~940 m elevational gradient. We examined how these community measures and taxonomic (Sørensen) and phylogenetic (UniFrac) beta diversity varied with elevation, precipitation, temperature and climatic stress.

Results

Species richness, phylogenetic diversity, stem density and basal area were positively correlated with elevation, with high-elevation plots exhibiting cooler temperatures, higher precipitation and lower stress. High-elevation assemblages also trended towards greater phylogenetic dispersion, which diminished at lower elevations and in drier, more stressful plots. Phylogenetic turnover was observed across the elevation gradient, and species evolutionary distinctiveness increased at lower elevations and under harsher abiotic conditions.

Main Conclusions

Harsher abiotic conditions at low elevations may act as a selective filter on plant lineages, leading to phylogenetically clustered low-diversity assemblages. These assemblages contained more evolutionarily distinct species that may contribute disproportionately to biodiversity. Conversely, milder abiotic conditions at high elevations may serve as refuges for drought-sensitive species, resulting in more diverse assemblages. Conservation practices that prioritize both high- and low-elevation habitats could promote the persistence of evolutionarily distinct species and areas of high biodiversity within the Central Indian landscape. Establishing connectivity between these habitats may provide a range of climatic conditions for species to retreat to or persist within as climates change.  相似文献   

17.
    
Neritids are ancient gastropod species which can live in marine, brackish water, and freshwater environments. In this study, we sequenced and annotated the mitochondrial genomes of five brackish water neritids (i.e., Clithon corona, Clithon lentiginosum, Clithon squarrosum, Neritina iris, and Septaria lineata). The mitogenomes ranged from 15,618 to 15,975 bp, and all contain 13 protein‐coding genes (PCGs), 22 tRNA genes, and two rRNA genes, with a closed ring structure. We calculated the Ka/Ks values of all 13 PCGs of Neritidae species, all ratios are less than 1, under purification selection. Phylogenetic analysis of the 13 PCGs showed that Neritimorpha is a sister group with Vetigastropoda and Caenogastopoda, genus Clithon is a sister group with Neritina and Septaria. Estimation of divergence time for all species of Neritidae showed that the main differentiation of Neritidae occurred in Cenozoic period (65 Mya), C. corona and C. lentiginosum were differentiated in the Cenozoic Neogene, the other three species diverged in the Cenozoic Paleogene. These results will help to better understand the evolutionary position of Neritidae and provide reference for further phylogenetic research on Neritidae species.  相似文献   

18.
边缘效应与生物多样性   总被引:31,自引:0,他引:31  
自从边缘效应提出以来,许多生态学家对它与生物多样性之间的关系进行了研究。大量的事实显示出边缘效应会表现出正效应或负效应,其结果并不完全一致。边缘效应的利用、管理和生物多样性保护是一项有意义而紧迫的工作。  相似文献   

19.
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.  相似文献   

20.
侧耳属主要种类ITS序列分析   总被引:5,自引:2,他引:5  
黄晨阳  陈强  高山  高巍  张金霞 《菌物学报》2010,29(3):365-372
对侧耳属16个种的38个菌株进行了ITS序列测定,统计分析种内和种间序列趋异度。结果表明,16个种的ITS序列种内趋异度很小,为0-0.007,其中Pleurotus djamor不同地理来源的3个菌株的趋异度为0.007。在16个种的种间ITS序列趋异度中,P.rattenburyi和P.djamor之间趋异度最大,为0.282;P.ostreatus和P.cornucopiae之间的趋异度最小,为0.003。利用ITS序列能够对侧耳属的大多种类进行有效鉴定。ITS序列差异2%-3%作为伞菌中种的鉴定临界值在侧耳属中并不合适。而对于P.ostreatus和P.cornucopiae的准确鉴定,仍需开发新的分类鉴定标记。以香菇为外群,用贝叶斯法构建的侧耳属系统发育树表明,系统发育树的部分节点十分可靠,后验概率值为0.96-1.0。  相似文献   

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