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1.
Ecosystem distributions are expected to shift as a result of global warming, raising concerns about the long-term utility of reserve systems based on coarse-filter ecosystem representation. We tested the extent to which proportional ecosystem representation targets would be maintained under a changing climate by projecting the distribution of the major ecosystems of Alberta, Canada, into the future using bioclimatic envelope models and then calculating the composition of reserves in successive periods. We used the Marxan conservation planning software to generate the suite of reserve systems for our test, varying the representation target and degree of reserve clumping. Our climate envelope projections for the 2080s indicate that virtually all reserves will, in time, be comprised of different ecosystem types than today. Nevertheless, our proportional targets for ecosystem representation were maintained across all time periods, with only minor exceptions. We hypothesize that this stability in representation arises because ecosystems may be serving as proxies for land facets, the stable abiotic landscape features that delineate major arenas of biological activity. The implication is that accommodating climate change may not require abandoning the conventional ecosystem-based approach to reserve design in favour of a strictly abiotic approach, since the two approaches may be largely synonymous.  相似文献   

2.
科尔沁沙地沙漠化过程中的物种多样性   总被引:59,自引:8,他引:59  
对内蒙古科尔沁地区沙漠化过程中物种多样性的变化特征进行了分析 ,依据植物种在各类型沙漠化土地的出现频率和不同沙漠化阶段各生活型植物种的组成 ,探讨了沙漠化过程中植物种绝灭和定居特点 .物种多样性指数分析表明 ,沙漠化过程是一个物种多样性衰减的过程 ,沙漠化首先导致特有种的绝灭 ,其次为稀有种和普通种 .从植物的生活型来看 ,多年生草本和灌木类植物受沙漠化影响最大 ,而 1年生草本和半灌木类植物可存活于沙漠化过程各个阶段 .在沙漠化过程中植物种的绝灭速率大于定居速率 .  相似文献   

3.
4.
Ⅰ期临床试验主要关心药物的毒性,目的是在给定的剂量水平中寻找最大耐受剂量(MTD).本文提出了基于药物毒性反应等级的up-and-down自适应设计,调查了该设计在各种变化的剂量一毒性关系下的运作特征.结果表明:该设计方法对提高建议MTD的精确度,以及保护病人,防止病人暴露在较高毒性剂量下方面,对Ⅰ期临床试验的设计实现了有意义的改善.  相似文献   

5.
城市绿地乡土树种对大气污染的适应性响应   总被引:1,自引:0,他引:1  
为探究华南乡土树种对东莞市不同绿地类型的适应性,将14种华南乡土树种分别栽植于四种绿地类型:工业绿地、道路绿地、城市公园和植物园,研究乡土树种的生理生态变化。各类型绿地的大气监测结果表明,道路绿地的各项大气污染指标明显高于其他绿地;工业区绿地的总悬浮颗粒物和氮氧化物浓度比植物园高;城市公园的总悬浮颗粒物浓度明显高于植物园。14个树种的生理生态研究结果表明,不同植物在各种绿地环境中适应策略各异,且随着污染强度的增加,多数植物净光合速率(Pn)和气孔导度(Gs)之间的相关系数降低,且Pn与Gs之间的相关系数变化不一致。14种华南乡土树种中,深山含笑、樟树、山杜英、黄栀子、胡氏青冈、九节、格木、黄果厚壳桂和华润楠等9个树种在不同污染环境下均表现出不同程度的敏感性,红鳞蒲桃和越南山龙眼对各种环境污染都不敏感,红叶石楠、假鹰爪和枫香在不同的污染环境中表现各异。  相似文献   

6.
Scenario-Led Habitat Modelling of Land Use Change Impacts on Key Species   总被引:1,自引:0,他引:1  
Accurate predictions of the impacts of future land use change on species of conservation concern can help to inform policy-makers and improve conservation measures. If predictions are spatially explicit, predicted consequences of likely land use changes could be accessible to land managers at a scale relevant to their working landscape. We introduce a method, based on open source software, which integrates habitat suitability modelling with scenario-building, and illustrate its use by investigating the effects of alternative land use change scenarios on landscape suitability for black grouse Tetrao tetrix. Expert opinion was used to construct five near-future (twenty years) scenarios for the 800 km2 study site in upland Scotland. For each scenario, the cover of different land use types was altered by 5–30% from 20 random starting locations and changes in habitat suitability assessed by projecting a MaxEnt suitability model onto each simulated landscape. A scenario converting grazed land to moorland and open forestry was the most beneficial for black grouse, and ‘increased grazing’ (the opposite conversion) the most detrimental. Positioning of new landscape blocks was shown to be important in some situations. Increasing the area of open-canopy forestry caused a proportional decrease in suitability, but suitability gains for the ‘reduced grazing’ scenario were nonlinear. ‘Scenario-led’ landscape simulation models can be applied in assessments of the impacts of land use change both on individual species and also on diversity and community measures, or ecosystem services. A next step would be to include landscape configuration more explicitly in the simulation models, both to make them more realistic, and to examine the effects of habitat placement more thoroughly. In this example, the recommended policy would be incentives on grazing reduction to benefit black grouse.  相似文献   

7.
低丘人工林林下植被物种多样性初步研究   总被引:24,自引:0,他引:24  
选取江西省泰和县狗丝茅岭低丘荒山人工造林l0a的人工生态系统中8种人工林主要类型和1个对照区,通过比较这些类型林下植被的物种多样性(物种丰富度和Shannon-Wiener指数)和相关的环境因子,揭示林下植被物种多样性的差异及其与环境因子之间的关系。结果显示:人工林类型(造林树种)、林分组成(纯林或混交林)和林分密度对物种多样性的影响较为明显,其中林分密度的影响最为显著:各人工林类型林下植被的Shannon—Wiener指数与物种丰富度具有大体相似的规律,即在相近造林密度下,不同造林树种其林下植被物种多样性以针叶纯林稍占优势,针阔混交林次之,而阔叶纯林相对较低:针叶林林下植被物种多样性虽然最高,但针叶林土壤的持水力相对较差,有机质含量也较低,而阔叶纯林相对较好,针阔混交林则最佳。  相似文献   

8.
MapDraw,在Excel中绘制遗传连锁图的宏   总被引:113,自引:7,他引:106  
刘仁虎  孟金陵 《遗传》2003,25(3):317-321
MAPMAKER是现今广泛使用的遗传连锁数据分析软件,然而其广泛使用的DOS版本却不具有连锁图绘制功能,给连锁作图工作带来了相当大的麻烦。为了解决这一问题,我们以大家广泛使用的数据处理软件Microsoft Excel为平台,编写了一个Excel宏——MapDraw来在轻松的操作中实现遗传连锁图的绘制。 Abstract:MAPMAKER is one of the most widely used computer software package for constructing genetic linkage maps.However,the PC version,MAPMAKER 3.0 for PC,could not draw the genetic linkage maps that its Macintosh version,MAPMAKER 3.0 for Macintosh,was able to do.Especially in recent years,Macintosh computer is much less popular than PC.Most of the geneticists use PC to analyze their genetic linkage data.So a new computer software to draw the same genetic linkage maps on PC as the MAPMAKER for Macintosh to do on Macintosh has been crying for.Microsoft Excel,one component of Microsoft Office package,is one of the most popular software in laboratory data processing.Microsoft Visual Basic for Applications (VBA) is one of the most powerful functions of Microsoft Excel.Using this program language,we can take creative control of Excel,including genetic linkage map construction,automatic data processing and more.In this paper,a Microsoft Excel macro called MapDraw is constructed to draw genetic linkage maps on PC computer based on given genetic linkage data.Use this software,you can freely construct beautiful genetic linkage map in Excel and freely edit and copy it to Word or other application.This software is just an Excel format file.You can freely copy it from ftp://211.69.140.177 or ftp://brassica.hzau.edu.cn and the source code can be found in Excel′s Visual Basic Editor.  相似文献   

9.
High-density Integrated Linkage Map Based on SSR Markers in Soybean   总被引:2,自引:0,他引:2  
A well-saturated molecular linkage map is a prerequisite for modern plant breeding. Several genetic maps have been developed for soybean with various types of molecular markers. Simple sequence repeats (SSRs) are single-locus markers with high allelic variation and are widely applicable to different genotypes. We have now mapped 1810 SSR or sequence-tagged site markers in one or more of three recombinant inbred populations of soybean (the US cultivar ‘Jack’ × the Japanese cultivar ‘Fukuyutaka’, the Chinese cultivar ‘Peking’ × the Japanese cultivar ‘Akita’, and the Japanese cultivar ‘Misuzudaizu’ × the Chinese breeding line ‘Moshidou Gong 503’) and have aligned these markers with the 20 consensus linkage groups (LGs). The total length of the integrated linkage map was 2442.9 cM, and the average number of molecular markers was 90.5 (range of 70–114) for the 20 LGs. We examined allelic diversity for 1238 of the SSR markers among 23 soybean cultivars or lines and a wild accession. The number of alleles per locus ranged from 2 to 7, with an average of 2.8. Our high-density linkage map should facilitate ongoing and future genomic research such as analysis of quantitative trait loci and positional cloning in addition to marker-assisted selection in soybean breeding.Key words: EST-derived SSR marker, integrated linkage map, microsatellite marker, polymorphism information content  相似文献   

10.
Indwelling and temporary medical delivery devices (i.e. catheters) are increasingly used in hospital settings, providing clinicians with useful tools to administer nutrients, draw blood samples and deliver drugs. However, they can often put patients at risk for local or systemic infections, including bloodstream infections and endocarditis. Microorganisms readily adhere to the surfaces and colonize them by forming a slimy layer of biofilm. Bacteria growing in biofilms exhibit an increased antibiotic resistance in comparison with planktonic cells. Consequently the antibiotic treatment of these medical device-associated infections frequently fails. Detechment resulting in the formation of microemboli is a further biofilm related complication. Since infections often involve increased morbidity and morality, prolonged hospitalization and additional medical costs, various strategies to prevent biofilm formation on implanted medical devices have been developed over the last two decades. In this paper we review and discuss the most significant experimental approaches to inhibit bacterial adhesion and growth on these devices.  相似文献   

11.
云南省4种陆生贝类的营养成分分析   总被引:4,自引:0,他引:4  
报道了云南省4种陆生贝类即褐云玛瑙螺(Achatina fulica)、金平坚螺(Camaena jinpingensis)、勐仑隐带螺(Cryptozona menglunensis)、勐仑环口螺(Cyclophorus menglunensis)的营养成分,并与猪肉、牛肉、鸡肉的营养成分进行比较。结果表明,这4种陆生贝类的蛋白质含量高,脂肪和糖类含量低,含有丰富的维生素和钙、磷、铁等无机元素,可作为优质保健食品进一步开发利用。  相似文献   

12.
应用RAMP分子标记探讨拟鹅观草属的种间关系   总被引:5,自引:0,他引:5  
采用RAMP (random amplified microsatellite polymorphism) 标记技术, 分析了拟鹅观草属9种1亚种和鹅观草属6 种植物之间的遗传变异和亲缘关系。33 个引物组合产生的310 条DNA扩增片段中, 286条(92 25%) 具有多态性, 每个引物组合产生5~13条多态性带, 平均为8 67条。利用310个RAMP标记, 在NTSYS pc软件中, 计算Jaccard遗传相似系数, 建立UPGMA聚类图。结果表明: (1) 物种间遗传差异明显, 具有丰富的遗传多样性; (2) 阿拉善鹅观草和大丛鹅观草与拟鹅观草属的物种聚类在一起, 表明它们与拟鹅观草属的亲缘关系较近, 而与本试验所分析的另外4个鹅观草属物种的亲缘关系较远; (3) RAMP分子标记可以将拟鹅观草属的物种分开, 而且形态相似、地理分布相同或相近的物种聚类在一起;(4) RAMP结果与形态学和细胞学的分析结果一致, 表明RAMP标记是评价拟鹅观草属种间关系十分有效的方法。  相似文献   

13.
Linkage-disequilibrium mapping (LDM) recently has been hailed as a powerful statistical method for fine-scale mapping of disease genes. After reviewing its historical background and methodological development, we present a general, mathematical, and conceptually coherent framework for LDM that incorporates multilocus and multiallelic markers and mutational processes at the marker and disease loci. With this framework, we address several issues relevant to fine-scale mapping and propose some efficient computational methods for LDM. We implement various LDM methods that incorporate population growth, recurrent mutation, and marker mutations, on the basis of a general framework. We demonstrate these methods by applying them to published data on cystic fibrosis, Huntington disease, Friedreich ataxia, and progressive myoclonus epilepsy. Since the genes responsible for these diseases all have been cloned, we can evaluate the performance of our methods and can compare ours with that of other methods. Using the proposed methods, we successfully and accurately predicted the locations of genes responsible for these diseases, on the basis of published data only.  相似文献   

14.
“拟自然”水景设计从解读自然水景生成规律出发,充分结合地形条件,通过计算机技术辅助模拟自然形态与生态过程,生成拟自然的水景观系统。本文运用Grasshopper软件,紧扣水景构成关键要素,构建“形态—坝高—水量”动态关联,并根据参数化设计逻辑进行算法编写,建立参数化设计模型,实现水量、水体形态、工程量的多要素统筹设计与动态调控,优化设计方案。  相似文献   

15.
Diversity Arrays Technology (DArT) provides a robust, high throughput, cost-effective method to query thousands of sequence polymorphisms in a single assay. Despite the extensive use of this genotyping platform for numerous plant species, little is known regarding the sequence attributes and genome-wide distribution of DArT markers. We investigated the genomic properties of the 7,680 DArT marker probes of a Eucalyptus array, by sequencing them, constructing a high density linkage map and carrying out detailed physical mapping analyses to the Eucalyptus grandis reference genome. A consensus linkage map with 2,274 DArT markers anchored to 210 microsatellites and a framework map, with improved support for ordering, displayed extensive collinearity with the genome sequence. Only 1.4 Mbp of the 75 Mbp of still unplaced scaffold sequence was captured by 45 linkage mapped but physically unaligned markers to the 11 main Eucalyptus pseudochromosomes, providing compelling evidence for the quality and completeness of the current Eucalyptus genome assembly. A highly significant correspondence was found between the locations of DArT markers and predicted gene models, while most of the 89 DArT probes unaligned to the genome correspond to sequences likely absent in E. grandis, consistent with the pan-genomic feature of this multi-Eucalyptus species DArT array. These comprehensive linkage-to-physical mapping analyses provide novel data regarding the genomic attributes of DArT markers in plant genomes in general and for Eucalyptus in particular. DArT markers preferentially target the gene space and display a largely homogeneous distribution across the genome, thereby providing superb coverage for mapping and genome-wide applications in breeding and diversity studies. Data reported on these ubiquitous properties of DArT markers will be particularly valuable to researchers working on less-studied crop species who already count on DArT genotyping arrays but for which no reference genome is yet available to allow such detailed characterization.  相似文献   

16.
用AFLP的方法分析中国白桦×欧洲白桦的78个F1个体,并按照拟测交作图策略,建立了中国白桦和欧洲白桦遗传连锁图谱。从群体的45对引物组合中分离出343个分离位点,χ^2检验表明,其中有311个符合1:1拟测交分离位点。在这些位点中168个来自中国白桦,143个来自欧洲白桦。软件分析表日月,中国白桦的168个位点构成9个连锁群,11个三联体和14个连锁对,55个为非连锁位点,连锁标记覆盖的总距离为1909.2cM,平均图距为16.9cM;来自欧洲白桦的143个位点构成12个连锁群,4个三联体和9个连锁对,21个为非连锁位点,连锁标记覆盖的总距离为1857.3cM,平均图距为15.2cM。  相似文献   

17.
Recent studies have countered the paradigm of seamount isolation, confounding conservation efforts at a critical time. Efforts to study deep-sea corals, one of the dominant taxa on seamounts, to understand seamount connectivity, are hampered by a lack of taxonomic keys. A prerequisite for connectivity is species overlap. Attempts to better understand species overlap using DNA barcoding methods suggest coral species are widely distributed on seamounts and nearby features. However, no baseline has been established for variation in these genetic markers relative to morphological species designations for deep-sea octocoral families. Here we assess levels of genetic variation in potential octocoral mitochondrial barcode markers relative to thoroughly examined morphological species in the genus Narella. The combination of six markers used here, approximately 3350 bp of the mitochondrial genome, resolved 83% of the morphological species. Our results show that two of the markers, ND2 and NCR1, are not sufficient to resolve genera within Primnoidae, let alone species. Re-evaluation of previous studies of seamount octocorals based on these results suggest that those studies were looking at distributions at a level higher than species, possibly even genus or subfamily. Results for Narella show that using more markers provides haplotypes with relatively narrow depth ranges on the seamounts studied. Given the lack of 100% resolution of species with such a large portion of the mitochondrial genome, we argue that previous genetic studies have not resolved the degree of species overlap on seamounts and that we may not have the power to even test the hypothesis of seamount isolation using mitochondrial markers, let alone refute it. Thus a precautionary approach is advocated in seamount conservation and management, and the potential for depth structuring should be considered.  相似文献   

18.
姜花属SRAP分子标记连锁图谱构建   总被引:8,自引:1,他引:7  
采用拟测交作图策略,利用白姜花×圆瓣姜花的F1群体87个单株,分别构建了父母本的基于SRAP标记的连锁图谱。通过筛选,414对引物中,92对引物可以检测到拟测交位点。在检测到的398个拟测交位点中,237个来自于父本圆瓣姜花,161个来自于母本。经过卡方(x^2)测验及连锁分析,父本中,203个标记进入23个连锁群,覆盖了1386.8cm;母本中,139个标记进入18个连锁群,覆盖了917.1cm。  相似文献   

19.
为探究植物对热带珊瑚岛高温、强光照、干旱、盐碱等极端环境的适应策略,分别以生长于海南文昌苗圃和移栽至热带珊瑚岛的29种植物为研究对象,对其叶片性状进行测定和比较分析。结果表明,与海南文昌的同种植物相比,热带珊瑚岛的草本植物除干物质含量增加外其他性状均无显著改变;而木本植物的比叶面积显著下降,叶片厚度和叶片干物质含量显著增加,海绵组织更厚且栅栏组织排列更紧密,但气孔长度、气孔密度及气孔面积指数无显著差异。岛上木本植株采取慢速投资-收益的资源获取策略,将更多的资源投入到叶片构建中从而增强逆境下的适应性,并且通过非气孔调节的方式提高光合与储水的潜力以抵御胁迫。栽植于热带珊瑚岛的29种植物能够采用更保守的资源利用策略,较好地适应干旱、强光照等胁迫环境,可用于热带珊瑚岛植被构建。  相似文献   

20.
以沙质草地优势物种猪毛蒿、胡枝子和糙隐子草为研究对象,利用开顶式生长室(OTC)模拟增温,研究降水减少20%、40%和60%与增温的交互作用对3种典型植物叶片光合气体交换特征及叶绿素荧光特征的影响,以揭示沙质草地3种优势植物对气候变化的响应规律。结果显示:(1)与自然温度相比,OTC模拟增温增加了猪毛蒿C_(i),显著降低了胡枝子G_(s)、P_(n)和T_(r)、糙隐子草G_(s)和P_(n)、猪毛蒿WUE和L_(s),也显著降低了猪毛蒿和胡枝子F_(v)/F_(m)和F_(v)/F_(o)。(2)无论增温与否,随着降水减少幅度的增加,猪毛蒿G_(s)和P_(n)呈下降趋势,且中度以上的干旱胁迫下(降水减少>40%)胡枝子和糙隐子草P_(n)显著低于对照。(3)在自然温度条件下,轻度干旱胁迫时(降水减少20%)猪毛蒿T_(r)显著低于对照,重度干旱胁迫时(降水减少60%)其WUE、F_(v)/F_(m)和F_(v)/F_(o)显著低于对照;重度干旱胁迫时,胡枝子C_(i)显著高于对照,差异幅度达10.7%,L_(s)显著低于对照,轻度干旱胁迫时(降水减少20%)其F_(v)/F_(m)和F_(v)/F_(o)显著高于中度以上的干旱胁迫;中度以上的干旱胁迫下糙隐子草T_(r)和G_(s)显著低于对照,重度干旱胁迫时,其C_(i)、F_(v)/F_(m)和F_(v)/F_(o)显著低于对照,WUE和L_(s)显著高于对照。(4)增温与降水减少交互作用下,所有处理猪毛蒿C_(i)均高于对照,差异幅度分别达4.5%,6.0%和8.4%;胡枝子T_(r)均显著低于对照,差异幅度达57.8%;重度干旱胁迫时猪毛蒿L_(s)和WUE显著低于对照,糙隐子草F_(v)/F_(m)和F_(v)/F_(o)随降水减少而降低,中度以上的干旱胁迫时其值显著低于对照。(5)相关性分析表明,3个优势物种的P_(n)与F_(v)/F_(m)和F_(v)/F_(o)均呈显著正相关关系,其中猪毛蒿和糙隐子草的P_(n)—F_(v)/F_(m)和P_(n)—F_(v)/F_(o)斜率明显高于胡枝子。研究表明,气候变暖会在一定程度上加剧降水减少对沙质草地3种群落优势物种光合作用的抑制。  相似文献   

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