The partitioning of Africa: statistically defined biogeographical regions in sub‐Saharan Africa

Aim To test whether it is possible to establish a common biogeographical regionalization for plants and vertebrates in sub‐Saharan Africa (the Afrotropical Region), using objective multivariate methods. Location Sub‐Saharan Africa (Afrotropical Region). Methods We used 1° grid cell resolution databases for birds, mammals, amphibians and snakes (4142 vertebrate species) and c. 13% of the plants (5881 species) from the Afrotropical Region. These databases were analysed using cluster analysis techniques to define biogeographical regions. A β(sim) dissimilarity matrix was subjected to a hierarchical classification using the unweighted pair‐group method with arithmetic averages (UPGMA). The five group‐specific biogeographical regionalizations were compared against a regionalization developed from a combined database, and a regionalization that is maximally congruent with the five group‐specific datasets was determined using a consensus classification. The regionalizations were interpreted against measures of spatial turnover in richness and composition for the five datasets as well as the combined dataset. Results We demonstrate the existence of seven well‐defined and consistent biogeographical regions in sub‐Saharan Africa. These regionalizations are statistically defined and robust between groups, with minor taxon‐specific biogeographical variation. The proposed biogeographical regions are: Congolian, Zambezian, Southern African, Sudanian, Somalian, Ethiopian and Saharan. East Africa, the West African coast, and the transitions between the Congolian, Sudanian and Zambezian regions are unassigned. The Cape area in South Africa, Afromontane areas and the coastal region of East Africa do not emerge as distinct regions but are characterized by high neighbourhood heterogeneity, rapid turnover of species and high levels of narrow endemism. Main conclusions Species distribution data and modern cluster analysis techniques can be used to define biogeographical regions in Africa that reflect the patterns found in both vertebrates and plants. The consensus of the regionalizations between different taxonomic groups is high. These regions are broadly similar to those proposed using expert opinion approaches. Some previously proposed transitional zones are not recognized in this classification.     

The world's biogeographical regions: cluster analyses based on bat distributions

Aim Both floral kingdoms and faunal regions have so far been intuitively defined. This study was conducted to compare these with an analytical regionalization based on cluster analyses in a fairly homogeneous, globally distributed group of organisms: the bats (order Chiroptera). This comparison was used to discuss the possibilities of employing clustering techniques in global biogeography. Location The study considered bat distributions world‐wide. Methods Analyses were conducted both for presence/absence of genera and species, and for the number of species in each genus. Clusters distinguished at selected dissimilarity values were mapped. Results A set of c. 10 regional clusters recurred in the analyses, broadly corresponding not only to the world's accepted faunal regions and subregions, but also to the floral kingdoms and subkingdoms. Main conclusions This study is an analytical confirmation of the fact that similar global distribution patterns are to be found in different groups of organisms. Cluster analyses can be used to refine global regionalization schemes, and, with the accumulation of such data for different taxa and ecologically defined groups, shared patterns can be used to draft one common global biogeographical regionalization. At the same time, differences between the regionalization schemes derived for different groups can be used to partial out the role of dispersal abilities, body size, evolutionary age, etc., in determining global distribution patterns.     

Do the Oaxacan Highlands represent a natural biotic unit? A cladistic biogeographical test based on vertebrate taxa

Aim  We analysed the distributional patterns of six terrestrial vertebrate taxa from the Oaxacan Highlands (Sierra Mazateca, Nudo de Zempoaltépetl and Sierra de Juárez) through a cladistic biogeographical approach, in order to test their naturalness as a biotic unit.
Location  The Oaxacan Highlands, Mexico.
Methods  The cladistic biogeographical analysis was based on the area cladograms of the Pseudoeurycea bellii species group (Amphibia: Plethodontidae), the genus Chlorospingus (Aves: Thraupidae), the genera Microtus , Reithrodontomys and Habromys , and the Peromyscus aztecus species group (Mammalia: Rodentia). We obtained paralogy-free subtrees, from which the components were coded in a data matrix for parsimony analysis. The data matrix was analysed with N ona through W in C lada .
Results  The parsimony analysis resulted in a single general area cladogram in which areas were fragmented following the sequence Sierra Madre Occidental, Trans-Mexican Volcanic Belt, Chiapas, Sierra Madre Oriental + Sierra Mazateca, Sierra Madre del Sur, Nudo de Zempoaltépetl and Sierra de Juárez.
Main conclusions  The general area cladogram shows that the Oaxacan Highlands do not constitute a natural unit. The Sierra Mazateca is the sister area to the Sierra Madre Oriental, whereas the Nudo de Zempoaltépetl and the Sierra de Juárez are closely related to the Sierra Madre del Sur. The events that might have caused these patterns include cycles of expansion and contraction of mountain pinyon, juniper and oak woodlands during the Pleistocene.     

Phylogenetic and biogeographical inferences for Pancratium (Amaryllidaceae), with an emphasis on the Mediterranean species based on plastid sequence data

The phylogenetics and biogeography of Pancratium (Amaryllidaceae) were investigated, with a focus on the Mediterranean and adjacent areas, with the aim of contributing new information towards a better understanding of the evolutionary history of the genus and the taxonomic placement of P. linosae and P. hirtum. To address these questions, we sequenced four plastid DNA markers: the ndhF and rbcL genes, the trnL^(UAA)–trnF^(GAA) intergenic spacer and the trnL^(UAA) intron, analysing them using parsimony, likelihood and Bayesian approaches. The results show that the relationships among the majority of the species are resolved; however, the relationships of one of the major clades of the genus are unresolved compared with the others. The phylogenetic and the dispersal–vicariance analyses show that Pancratium appears as a well‐structured group with interesting patterns of speciation. Notably, P. arabicum and P. linosae fall within the P. maritimum complex. In addition, P. hirtum is identical, in terms of plastid DNA sequences, to the P. trianthum accessions. The results provide new insights and help to formulate new working hypotheses for evolutionary biology of the genus. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170 , 12–28.     

不同地域野生欧李及其近缘植物亲缘关系的RAPD分析

利用RAPD分子标记技术对21个不同地域欧李及其近缘种属植物(桃、杏、李、樱桃)进行了遗传亲缘关系及分类研究。结果表明,用于不同地域野生欧李分析的25条引物中,共扩增出441个清晰可用的DNA片段,其中多态性位点366个,多态性比为82.99%。在遗传相似系数为0.71时,可将中国野生欧李资源划分为3个大的区域,分别为东北分布群、华北华东分布群与中西部分布群。用于欧李及其近缘种属植物分析的20条引物中,共扩出多态性带683条,多态性比率为98.99%。聚类分析表明,在遗传相似系数为0.61时,欧李与其近缘种属植物分为3大类;欧李与麦李的亲缘关系最近,与桃亲缘关系最远。     

Insights into the evolutionary history of Cervus (Cervidae,tribe Cervini) based on Bayesian analysis of mitochondrial marker sequences,with first indications for a new species

Molecular phylogeny and evolutionary history of Cervus, the most successful and widespread cervid genus, have been extensively addressed in Europe, fairly in eastern Asia, but scarcely in central Asia, where some populations have never been phylogenetically investigated with DNA‐based methods. Here, we applied a coalescent Bayesian approach to most Cervus taxa using complete mitochondrial cytochrome b gene and control region to provide a temporal framework for species differentiation and dispersal, with special emphasis on the central Asian populations from the Tarim Basin (C. elaphus bactrianus, C. elaphus yarkandensis) and Indian Kashmir (C. elaphus hanglu) aiming at assessing their phylogenetic and phylogeographic patterns. Red deer (C. elaphus), wapiti (C. canadensis) and sika deer (C. nippon) are confirmed as highly differentiated taxa, with genetic distances, divergence times and phylogenetic positions compatible with the rank of species. Similarly, the red deer of the Tarim group, hitherto considered as subspecies of C. elaphus, showed a comparable pattern of genetic distinction in the phylogeny and, according to our results, are thus worthy of being raised to the species level. The systematic position of the endangered red deer from Indian Kashmir is assessed here for the first time, and implications for its conservation are also outlined. Based on phylogeny and divergence time estimates, we propose a novel evolutionary pattern for the genus Cervus during the Mio/Pliocene, in the light of palaeo‐climatological information.     

A conceptual framework for ecosystem management based on tradeoff analysis

Three dimensions (natural, social and economic factors) in tradeoff analysis have not been focused in ecology. It is necessary to consider the multi-dimensions through a tradeoff analysis of disturbances to find their positive and negative effects (referred to as two-sidedness). We proposed an 11-step approach to integrate the concepts, methods and examples to understand ecological two-sidedness. We recommend that: (1) ecological complexity and large-scale systematic perspectives need to be integrated; (2) disparate disciplines should be integrated to classify the two-sidedness indicators; (3) models should be adopted to define the characteristic metrics of disturbed ecosystems; (4) researchers need to reconsider evaluation standards and for each indicator with marginal changes; and (5) initial decision-making should refer to the two-sidedness value and that final decision-making should be subject to debate. This approach has great significance for ecosystem management because decision-makers can obtain the superiority and inferiority of disturbance strategies and select optimal strategy.     

基于随机森林模型的国家重点保护陆生脊椎动物物种优先保护区的识别

准确可靠地识别国家重点保护陆生脊椎动物物种的优先保护区,是生物多样性保护的热点问题之一。采用随机森林(random forests)模型,基于12个环境变量,对中国263种国家重点保护陆生脊椎动物建模,并预测各个物种在背景点的适生概率,迭加计算得到国家重点保护陆生脊椎动物物种的生境适宜性指数。此外,基于对生境适宜性指数的空间自相关分析,识别和确定国家重点保护陆生脊椎动物物种优先保护区,并对优先保护区目前的被保护情况进行分析。结果表明,国家重点保护陆生脊椎动物物种的优先保护区的面积为103.16万km~2,约占我国国土面积的10.90%。优先保护区主要分布在我国的西部地区,包括西南地区的秦岭-大巴山山区、云南省与印度及缅甸的交界地区、武陵山山区、喜马拉雅山-横断山脉山区、阿尔泰山脉山区、天山山脉山区、昆仑山山脉山区;东北的大、小兴安岭、东北-华南沿海地区及长江中下游地区有少量分布。优先保护区中被保护的面积为50.40万km~2,占优先保护区总面积的48.86%,保护率偏低,未被充分保护。利用系统聚类分析,将未被保护的优先保护区划分成3种优先保护顺序,以期为相关部门的决策提供科学依据,更好地保护生物多样性。     

南水北调中线水源区弃耕地草本植被演替初步研究

以南水北调中线水源区不同年限的退耕弃荒地为研究对象,分析了其草本植被恢复阶段的群落学特征,用聚类分析和极点排序的方法对各群落类型进行了划分,探讨了其自然演替规律,并对弃耕地植被恢复的一般机理进行了初步探讨。结果表明,草本植被恢复演替过程可明显分为以下几个阶段：荠菜(Capsella bursa—pastoris) 铁苋菜(Acalypha australis) 小白酒草(Conyza canadensis)群落(退耕1年);小白酒草(Conyza canadensis) 灰绿藜(Chenopodium glaucum)群落(退耕2年);艾蒿(Artemisia argyi) 小白酒草(Conyza canadensis) 猪毛蒿(Artemisia scoparia)群落(退耕3～6年);白茅(Imperata cylindrica) 牛尾蒿(Arternisia subdigitata) 野艾蒿(Artemisia lavandulaefolia) 狗尾草(Setaria viridis)群落(退耕7～12年^ )。退耕3年时群落已经趋于稳定,草本植被基本上得到恢复。     

A method for screening copper-tolerant rice (Oryza sativa L.) cultivars based on hydroponic experiments and cluster analysis

A method for screening copper (Cu)-tolerant rice cultivars was studied by combining hydroponic experiments and cluster analysis, and the classification of cultivars in Cu stress tolerance was done. In the first hydroponic experiment, seedlings of Jiahe991 and Xiushui114 were planted in nutrient solution with different Cu²⁺ concentrations from 10 to 1800 μg/L. Results indicated that the toxic threshold of Cu concentration in solution ranged from 900 to 1200 μg/L, since SPAD (Soil and Plant Analyzer Development, SPAD-502, a portable chlorophyll meter, Minolta Camera Co. Ltd., Japan) values of leaves and seedlings biomass of the treatments with ≥900 and/or 1200 µg/L were significantly lower than the control. The second experiment was conducted with 16 local rice cultivars under three Cu treatments (10, 1000, and 1500 μg/L). The 16 cultivars were well classified into tolerant, normal, and sensitive groups as a result of cluster analysis based on the relative SPAD (Soil and Plant Analyzer Development, SPAD-502, a portable chlorophyll meter, Minolta Camera Co. Ltd., Japan) value, shoot and root dry weights, root length and root dehydrogenase activity, and oxidizing capacity and shoot Cu concentration. Xiushui123, Xiushui134, Jiahe991, and Xianghu301 belonged to the tolerant group; Xiushui137 belonged to the sensitive group. The cluster analysis based on hydroponic experiments is an effective method for identifying rice cultivars that are tolerant to Cu stress. In addition, four cultivars (Xiushui123, Xiushui134, Jiahe991, and Xianghu301) are recommended in local practice.     

水土流失治理新范式:基于流域过程模拟和情景分析的方法

随着土壤侵蚀问题的日益突出,水土流失治理逐渐成为实现区域可持续发展的当务之急.通过在试验小流域实施治理措施并评价其效益是水土流失治理的传统范式,但这种范式存在试验周期长、可重复性差、资金和人工技术投入大、推广性差等局限性,已不能适应当前水土流失治理的需要.近年来兴起的基于流域过程模拟的情景分析方法在定量模拟流域过程对地理变量响应的基础上,通过评价不同治理措施的环境、生态和经济效益,探索能够协调经济发展与环境保护关系的水土流失治理措施.该方法能够在无需大范围工程实施和实地观测的情况下对各种治理措施的效益进行评价,花费少,灵活性强,在水土流失治理措施的决策制定中具有较大优势.本文详细阐述以情景分析方式作为水土流失治理新范式的基本思路,通过实例分析,演示新范式在治理流域水土流失中的应用,并展望新范式在流域治理中的未来发展趋势.     

A fluorescent magnetic nanosensor for imidacloprid based on the incorporation of polymer dots and Fe3O4 nanoparticles into the covalent organic framework

A magnetic nanoprobe was designed for imidacloprid by encapsulating nonconjugated polymer dots (NCPDs) and Fe₃O₄ nanoparticles in the covalent organic framework (COF). The fluorescence intensity of the COF-based nanocomposite is markedly suppressed by imidacloprid. As the absorption spectrum of imidacloprid was close to the band-gap of the NCPDs, and due to the presence of a nitro group (as an electron acceptor), the electrons can be easily transferred from the conduction band of NCPDs to the LUMO of imidacloprid, so fluorescence quenching was more likely to have been caused by the electron transfer process. The COF-based nanosensor was used for the determination of imidacloprid in the linear range 1.3–130 nM with a detection limit of 1.2 nM. The high sensitivity of the nanoprobe for imidacloprid is due to the combination of COF benefits (accumulation of the imidacloprid into the COF cavities) and the high adsorption ability of the Fe₃O₄ nanoparticles, which leads to further enrichment of imidacloprid. The magnetic nature of the nanocomposite enables the preconcentration and easy separation of the analyte, and so reduces matrix interference and lowers the detection limits. The practicality of this nanoprobe was confirmed by quantification of imidacloprid in the wastewater and fruit juice samples.     

A rapid method for constructing precaution maps based on a simple virtual ecology model: a case study on the range expansion of the invasive aquatic species Limnoperna fortunei

Before invasion, or in its early stages, information on the invader in target areas is generally extremely limited. In such situations, managers must select focal areas in which to concentrate control and mitigation efforts. Here, we discuss a rapid method for selecting areas in which to control invasive aquatic species based on limited information. We used a simple cellular automata model that does not require species-specific information, but simulates the process of invasive species expansion and includes observed expansion progress to detect keystone areas. As a case study, we simulated the expansion of an invasive aquatic mussel, Limnoperna fortunei, in Ibaraki Prefecture, Japan, and detected the areas in which control efforts should be concentrated. To some extent, our model was able to predict the expansion of L. fortunei from the initial detected invasion to the current distribution. We predicted areas with a high potential of spreading and areas that would suffer from high propagule pressure. Results revealed a mismatch between areas with high spread potential and those with high propagule pressure. Managers should concentrate their invasion prevention efforts in the former because these are likely to have a greater long-term influence. Additionally, we predicted future expansion from the current distribution and showed that current scattered populations could merge naturally. Our approach is useful for establishing a management plan before or in the early stages of invasion.