中国生物多样性在线数据处理平台的构建

高质量的生物多样性数据能够为生物多样性的研究与保护提供数据支撑。目前研究人员开发了大量的生物多样性数据处理软件或工具, 包括工作流系统、R语言包、Python语言包和Excel工具等, 但是使用这些软件或工具需要用户安装相应的软件客户端, 并掌握一定的编程语言、软件开发和复杂的Excel公式等知识和技能。为降低用户的学习成本和使用门槛, 本文采用了Browser/Server模式设计技术、Web技术、可视化技术、响应式开发技术、网络爬虫技术、数据处理技术和Solr智能检索技术等, 针对不同维度的生物多样性数据设计和开发了相应的数据处理模块, 构建了中国生物多样性在线数据处理平台(http://dp.iflora.cn/)。该平台能够有效地帮助科研人员对物种名称、地理位置、时间日期和经纬度等数据进行处理, 并提供数据格式转换、数据质量评测和资源统计分析等辅助功能, 帮助科研人员实现零代码和低门槛地处理生物多样性数据, 提供便捷、高效和简单的数据清洗、校正、转换和整合等数据处理渠道, 为生物多样性研究和保护提供信息化技术支持与服务。     

呼伦贝尔草地植物群落与土壤化学计量学特征沿经度梯度变化

植物化学计量学特征在大尺度上主要受纬度和经度两个因素影响。纬度梯度上温度因子变化对植物化学计量特征的影响已有大量研究,但是关于经度梯度上降雨因子变化对植物化学计量特征影响的研究却较少。选取呼伦贝尔草原,研究经度梯度上植物化学计量特征和土壤养分指标的变化规律,从经度梯度和养分供给两方面分析植物群落化学计量特征的变化规律,研究结果如下:1)植物群落叶片C含量变化范围为440.76—452.72 mg/g,N含量变化范围为17.79—30.88 mg/g,P含量变化范围为1.31—1.71 mg/g;群落叶片C含量、C/N随经度升高显著增加;群落叶片N含量随经度升高显著下降;植物群落P含量也呈下降趋势,但是关系不显著;植物群落C、N和P元素总量随着经度升高而显著增加。2)0—10 cm土壤全碳、全氮、全磷、有机碳受降雨量变化和植物群落元素总量影响,随着经度梯度升高而增加;但土壤铵态氮、硝态氮在经度梯度上没有表现出规律性的变化趋势。3)土壤全碳、有机碳、全氮、全磷和速效磷与植物群落叶片C、N和P含量没有显著相关关系,但与植物群落C、N和P元素总量呈显著正相关关系。该区土壤有效磷含量(8.13 mg/kg)高于全球平均值(7.65 mg/kg),但植物群落叶片磷含量平均值(1.5 mg/g)低于全球平均值(1.77 mg/g)。通过研究结果推测:植物通过对气候条件的长期适应,群落水平C、N和P含量沿经度梯度形成一定的分布格局;降雨量影响植物群落元素积累的总量,从而与土壤养分含量呈显著正相关关系;植物叶片P含量低的原因并非是由于土壤中磷的供给不足所致,而是植物对环境长期适应形成的策略。     

气候假说对内蒙古草原群落物种多样性格局的解释

物种丰富度的地理格局是宏观生态学和生物地理学的中心议题之一。本文基于内蒙古草原192个野外样地的调查数据, 结合各样地年平均气温、年降水量等9个气候因子, 探讨内蒙古草原物种丰富度格局及其主导因素, 以确定气候假说在该区的适用性。结果表明: (1)内蒙古草原物种丰富度经度格局显著, 呈现沿经度升高而增加的趋势, 同时由于经纬度的共线性, 也呈现出沿纬度升高而增加的趋势。(2)方差分解显示, 能量单独解释率为2.7%, 水分单独解释率为11.4%, 水分和能量共同解释率为46.3%, 未解释部分为39.6%, 可见能量与水分的共同作用在物种丰富度格局形成中占主导地位, 支持水热动态假说。这说明水热动态假说适用于解释内蒙古草原物种丰富度 格局。     

Stoichiometric characteristics of carbon,nitrogen and phosphorus in Phyllostachys edulis forests of China

Aims Stoichiometric ratios of carbon (C), nitrogen (N) and phosphorus (P) are important characteristics of the ecological processes and functions. Studies on population ecological stoichiometry can refine the content of flora chemometrics, determine the limited nutrient, and provide data for process-based modeling over large scale. Phyllostachys edulis is an important forest type, whose area accounts for 74% of total bamboo forest area in Southern China. However, little is known about the ecological stoichiometric in P. edulis. This study aimed to reveal C:N, C:P and N:P stoichiometry characteristics of the “plant-soil-litter” continuum and to provide a better understanding nutrient cycling and stability mechanisms in P. edulis forest in China. Methods The data were collected from the published literature containing C、N、P content in leaf or surface soil (0-20 cm) or littefall in P. edulis forests. Important findings 1) The leaf C, N, P content were estimated at 478.30 mg·g^-1, 22.20 mg·g^-1, 1.90 mg·g^-1 in P. edulis, and the corresponding C: N, C: P and N: P were 26.80, 299.60 and 14.40, respectively. Soil C, N, and P content in 0-20 cm were 21.53 mg·g^-1, 1.66 mg·g^-1, 0.41 mg·g^-1, with ratios of 14.20 for C:N, 66.74 for C:P and 4.28 for N:P. The C, N and P contents were 438.49 mg·g^-1, 13.39 mg·g^-1, 0.86 mg·g^-1 for litterfall, with the litter C:N, C:P and N:P being 25.53, 665.67, 22.55, respectively. 2) In the plant-soil-litter system in P. edulis forest, leaf had higher C:N, litter had higher C:P and N:P, while soil were the lowest. The N, P resorption rate was 39.68% and 54.74%, indicating that P. edulis forest growth and development was constrained by P or by both of N and P in China. 3) N content and N:P in leaf showed a tendency to increase with latitude, while the C:N of leaf declined with latitude. N:P of leaf increased with longitude, but the P content and the C:N of leaf showed a opposite trend. C: N of soil increased with longitude, whereas the N content of soil declined longitude. The N content of litter declined with longitude. 4) The leaf N content was negatively correlated with mean annual temperature and mean annual precipitation, but being more sensitive to temperature than precipitation. The positive correlations between N content and latitude support “Temperature-Plant Physiological” hypothesis, reflecting an adaptive strategy to environmental conditions.     

Variations of male cuticular hydrocarbons with geoclimatic variables: an adaptative mechanism in Drosophila melanogaster?

7-tricosene (7T) and 7-pentacosene (7P) are the major components of cuticular hydrocarbons in Drosophila simulans and D. melanogaster males. A chemical study of 16 isofemale lines of D. melanogaster sampled at the first and eighth generations in laboratory conditions showed the stability of chromatographical profiles. Then a large scale study of male 7T/7P polymorphism was performed with 85 populations of D. melanogaster and 29 of D. simulans collected all over the world. There were significant correlations of the values of the balanced ratio (7T − 7P)/(7T + 7P) with geo-climatic parameters, such as latitude, longitude, mean temperature, temperature range and vapour pressure. Parallel variations were also reported for the homologous linear alkanes (23 and 25 Carbon atoms) but not for the longer branched alkanes (27 and 29 Carbon atoms). No correlation was significant for the D. simulans populations studied. In this species a similar polymorphism of 7T/7P was found but restricted to a few populations from West Equatorial Africa. This revised version was published online in July 2006 with corrections to the Cover Date.     

Large‐scale longitudinal gradients of genetic diversity: a meta‐analysis across six phyla in the Mediterranean basin

Biodiversity is the diversity of life at all scales, from genes to ecosystems. Predicting its patterns of variation across the globe is a fundamental issue in ecology and evolution. Diversity within species, that is, genetic diversity, is of prime importance for understanding past and present evolutionary patterns, and highlighting areas where conservation might be a priority. Using published data on the genetic diversity of species whose populations occur in the Mediterranean basin, we calculated a coefficient of correlation between within‐population genetic diversity indices and longitude. Using a meta‐analysis framework, we estimated the role of biological, ecological, biogeographic, and marker type factors on the strength and magnitude of this correlation in six phylla. Overall, genetic diversity increases from west to east in the Mediterranean basin. This correlation is significant for both animals and plants, but is not uniformly expressed for all groups. It is stronger in the southern than in the northern Mediterranean, in true Mediterranean plants than in plants found at higher elevations, in trees than in other plants, and in bi‐parentally and paternally than in maternally inherited DNA makers. Overall, this correlation between genetic diversity and longitude, and its patterns across biological and ecological traits, suggests the role of two non‐mutually exclusive major processes that shaped the genetic diversity in the Mediterranean during and after the cold periods of the Pleistocene: east‐west recolonization during the Holocene and population size contraction under local Last Glacial Maximum climate in resident western and low elevation Mediterranean populations.     

Geographical gradients in seed mass in relation to climate

Aim To determine whether latitudinal and longitudinal gradients in seed mass are related to variation in climatic features including temperature, solar radiation and rainfall. Location Australia. Methods Seed mass was estimated from over 1600 provenances covering the latitudinal and longitudinal extents of 34 perennial Glycine taxa in Australia. Climatic data were obtained from ANUCLIM 5.1 for collection locations based on long‐term meteorological records across Australia. These climatic data were subject to principal components analysis to extract three components as climatic indices. Generalized linear models were used in three separate sets of analyses to evaluate whether seed mass–latitude and seed mass–longitude relationships persisted after taking climatic variation into account. First, relationships were examined across species in analyses that did not explicitly consider phylogenetic relationships. Secondly, phylogenetic regressions were performed to examine patterns of correlated evolutionary change throughout the Glycine phylogeny. Within‐species analysis was also performed to examine consistency across different taxonomic levels. Results Geographical variation in seed mass among species was related primarily to temperature and solar radiation, while rainfall was much less influential upon seed mass. Partialing out the influence of temperature and solar radiation in models resulted in the disappearance of significant seed mass–latitude and seed mass–longitude relationships. Patterns within species were generally consistent with patterns among species. However, in several species, factors additional to these climatic variables may contribute to the origin and maintenance of geographical gradients in seed mass, as significant seed mass–latitude and seed mass–longitude relationships remained after controlling for the influence of climatic variables. Main conclusions Our empirical results support the hypotheses that (1) seed mass is larger at low latitudes and in the interior of the Australian continent due to increased metabolic costs at high temperatures, and that (2) higher levels of solar radiation result in an increase in the availability of photosynthate, which in turn leads to an increase in biomass for the production of large seeds. In effect, our findings show that greater energy is available precisely where needed, that is, where high temperatures require large seed mass on the basis of metabolic requirements.