Isolation and introgression in the Intermountain West: contrasting gene genealogies reveal the complex biogeographic history of the American pika (Ochotona princeps)

Aim We studied the history of colonization, diversification and introgression among major phylogroups in the American pika, Ochotona princeps (Lagomorpha), using comparative and statistical phylogeographic methods. Our goal was to understand how Pleistocene climatic fluctuations have shaped the distribution of diversity at mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) loci in this alpine specialist. Location North America’s Intermountain West. Methods We accumulated mtDNA sequence data (c. 560–1700 bp) from 232 pikas representing 64 localities, and sequenced two nuclear introns (mast cell growth factor, c. 550 bp, n = 148; protein kinase C iota, c. 660 bp, n = 139) from a subset of individuals. To determine the distribution of major mtDNA lineages, we conducted a phylogenetic analysis on the mtDNA sequence data, and we calculated divergence times among the lineages using a Bayesian Markov chain Monte Carlo approach. Relationships among nuclear alleles were explored with minimum spanning networks. Finally, we conducted coalescent simulations of alternative models of population history to test for congruence between nDNA and mtDNA responses to Pleistocene glacial cycles. Results We found that: (1) all individuals could be assigned to one of five allopatric mtDNA lineages; (2) lineages are associated with separate mountain provinces; (3) lineages originated from at least two rounds of differentiation; (4) nDNA and mtDNA markers exhibited overall phylogeographic congruence; and (5) introgression among phylogroups has occurred at nuclear loci since their initial isolation. Main conclusions Pika populations associated with different mountain systems have followed separate but not completely independent evolutionary trajectories through multiple glacial cycles. Range expansion associated with climate cooling (i.e. glaciations) promoted genetic admixture among populations within mountain ranges. It also permitted periodic contact and introgression between phylogroups associated with different mountain systems, the record of which is retained at nDNA but not mtDNA loci. Evidence for different histories at nuclear and mtDNA loci (i.e. periodic introgression versus deep isolation, respectively) emphasizes the importance of multilocus perspectives for reconstructing complete population histories.     

红豆杉高产细胞系快速建立和更新的新方法

目的：通过优化培养基和培养条件,建立太行红豆杉速生细胞系,为红豆杉细胞工厂化生产提供原种细胞系和繁殖技术。方法：以太行红豆杉为材料,筛选B5、WPS、MS等3种培养基和6-卞基嘌呤（6-BA）、萘乙酸（NAA）、2,4-二氯苯氧乙酸（2,4-D）等3种激素组合,采用液体、半固体、纸桥共3种培养方法继代培养并筛选高产细胞系。结果：B5＋NAA（1.0mg/L）＋6-BA（0.5mg/L）＋2,4-D（1.0mg/L）为最适愈伤组织诱导培养基,诱导率达100%;B5＋NAA（1.0～1.5mg/L）＋2,4-D（1.5～2.0mg/L）＋6-BA（0.5mg/L）为最佳继代培养基,生长量最高可达0.30g/（g·d）（鲜重）。结论：初步建立了红豆杉细胞系快速建立和繁殖新方法,用半固体培养产生初代细胞系、液体培养将细胞系同步化、纸桥培养快速繁殖细胞系,并通过检测紫杉醇含量不断更新细胞系。该细胞系体系建立方法简单,纯化速度快,易更新,产物细胞系可作为工厂化生产的原种细胞系。     

新疆阿尔泰山南麓平茶渍属地衣3个中国新记录种

平茶渍属(Aspicilia)是地衣型真菌的重要类群之一。该类真菌在干旱、半干旱地区尤为丰富,因此在地处半干旱区的新疆,其分布也极其多样。该研究对采自新疆阿尔泰山南麓可可托海风景区的平茶渍属地衣标本,从形态解剖、化学显色反应及薄层层析法和生境等多个角度进行了综合分析,发现中国新记录种3个,分别为博伊金平茶渍(Aspicilia boykinii)、烟色平茶渍(A.fumosa)和斯氏平茶渍(A.sipeana)。提供了这3个新记录种的外部宏观形态和内部解剖结构彩色图。     

Natural‐Channel‐Design Restorations That Changed Geomorphology Have Little Effect on Macroinvertebrate Communities in Headwater Streams

Stream restorations that increase geomorphic stability can improve habitat quality, which should benefit selected species and local aquatic ecosystems. This assumption is often used to define primary restoration goals; yet, biological responses to restoration are rarely monitored or evaluated methodically. Macroinvertebrate communities were inventoried at 6 study reaches within 5 Catskill Mountain streams between 2002 and 2006 to characterize their responses to natural‐channel‐design (NCD) restoration. Although bank stability increased significantly at most restored reaches, analyses of variation showed that NCD restorations had no significant effect on 15 of 16 macroinvertebrate community metrics. Multidimensional scaling ordination indicated that communities from all reach types within a stream were much more similar to each other within any given year than they were in the same reaches across years or within any type of reach across streams. These findings indicate that source populations and watershed‐scale factors were more important to macroinvertebrate community characteristics than were changes in channel geomorphology associated with NCD restoration. Furthermore, the response of macroinvertebrates to restoration cannot always be used to infer the response of other stream biota to restoration. Thus, a broad perspective is needed to characterize and evaluate the full range of effects that restoration can have on stream ecosystems.     

长白山不同演替阶段森林植物功能性状及其与地形因子间的关系

植物功能性状是近年来生态学研究的热点。不同种群功能性状的差异决定竞争优势,导致群落结构和性质发生改变,进而演替。以长白山森林演替过程中4个阶段的典型群落为研究对象,分析了长白山地区森林不同层次优势种的茎叶功能性状之间的关系、功能性状与地形因子的关系,并对不同演替阶段群落功能性状进行了比较。结果发现,比叶面积(SLA)与叶氮浓度(LNC)和茎磷浓度(SPC)正相关,与叶干物质质量(LDMC)负相关;叶厚度(LT)与LDMC负相关;LNC与LPC、SNC和LDMC呈正相关;茎氮浓度(SNC)与茎磷浓度(SPC)正相关;茎组织密度(STD)与LNC、SNC正相关。通过灰色关联度分析发现,海拔对SLA、LNC、LPC、STD、SPC影响最大;坡向对于LT、LDMC影响最大;坡位对SNC影响最大。各演替群落间的乔木层功能性状均有显著差异,灌木层的功能性状无显著差异,而草本层除了LDMC、LPC、SNC有显著差异外,其它指标均无显著差异;SLA、STD、LNC随演替的进行呈现明显增加趋势,LDMC、LPC随演替呈减少的趋势。LDMC和SLA是能体现群落演替差异的主要功能性状。     

北京山地植物多样性优先保护地区评价

为促进北京市植物多样性的保护及自然保护区的合理建设与布局,以2001～2006年间在北京市13个自然保护区、森林公园或者风景名胜区内实地调查的1168个样地数据为基础,根据在北京市分布的25种珍稀濒危植物种,以及丰富度高的群落类型、面积较大的天然森林群落类型和具有重要生态功能的森林群落的评定结果,采用等级赋值的方法,利用地理信息系统软件从植物物种和植物群落方面综合评定了北京市山地植物多样性的优先保护地区.评定出综合优先保护地区总面积为184474.64hm2,约占市国土面积的11.25%,其中一级优先保护地区总面积24850.50hm2,二级优先保护地区总面积78606 60hm2,三级优先保护地区总面积81017.54hm2.优先保护地区主要分布于怀柔区、延庆县、房山区和密云县等远郊区县,结合北京市自然保护区分布现状,提出了北京市自然保护区建设优化方案.     

秦岭川金丝猴的一次家庭雄性替代

家庭雄性替代已在亚洲叶猴的许多种类中有所报道。 2 0 0 3年 ,我们在一种亚洲叶猴———秦岭的川金丝猴 (Rhinopithecusroxellana)的一个单雄家庭中观察到一次完整的家庭雄性替代过程。此次替代发生于 4月 2 8日 - 5月 2日的五天时间内。在家庭雄性发生替代后的第六个月 ,该家庭中的婴猴消失。本文是首次对野生川金丝猴家庭雄性替代进行详细的报道。通过本次观察证明野生川金丝猴的确存在家庭雄性替代的现象。且像亚洲叶猴的许多种类一样 ,野生川金丝猴的家庭雄性替代同样发生于产仔季节和交配季节之间。但我们仍无法确定在本次雄性替代中婴猴最终的消失是否是雄性杀婴的结果     

天山南麓山前平原植物群落物种多样性及空间分异研究

荒漠灌丛是天山南麓山前平原主要植被类型.本研究定量分析了山前平原植物群落物种多样性及生境尺度异质性的影响.结果表明:(1)天山南麓山前平原的植物群落多样性指数Simpson、均匀度指数McIntosh及丰富度指数Margalef都较低,在地貌带的过渡上,植物分布呈现均匀化.(2)海拔和地下水埋深是影响天山南麓山前平原植物群落物种多样性的重要环境指标.海拔梯度与物种多样性指数Simpson、Margalef及McIntosh均呈显著的线性正相关关系,物种多样性均随海拔高度的增加而增加;地下水埋深与物种多样性指数呈极显著的线性负相关关系,物种多样性随地下水埋深的增加而减小.(3)土壤含盐量与物种多样性指标无显著关系,但土壤含盐量与地下水埋深相关性显著,这是天山南麓山前平原土壤盐分空间异质性的一个重要特点.土壤盐分含量变化影响着植物群落物种组成,随土壤盐分含量增加,群落中盐生植物种类逐渐占据优势.(4)海拔的变化是决定天山南麓山前平原灌丛群落生境差异的主导因子.海拔差异表征了山前平原地貌、水文地质条件及土壤的变化,而随海拔变化的水热、水盐等干扰体系的差异则进一步导致了异质性的生境,进而影响不同植被类型中群落组成结构和多样性的差异.     

长白山溪流河岸带森林木本植物多样性沿海拔梯度分布规律

采用样带网格调查方法和α、β多样性指数分析方法,研究了长白山河岸带原始林和次生林群落木本植物多样性沿海拔梯度分布规律及其对采伐干扰的响应.结果表明：不同海拔区域河岸带原始林群落均由11～13个树种组成,其在群落中的地位随海拔升高而发生变化,阔叶树种优势地位逐步被针叶树种所取代,采伐干扰不仅改变了群落树种丰富度及其在群落中的地位,而且使针叶树种取代阔叶树种的趋势有所增强;河岸带原始林群落物种多样性沿海拔梯度呈现出中、低海拔区域相对较高且比较恒定(2.454～2.544),高海拔区域(2.250)下降的分布规律,采伐干扰改变了其沿海拔梯度分布格局(波动型),加大了不同海拔区域群落间的波动性(2.174～2.692);河岸带原始林群落树种沿海拔梯度的变动速率相对较低(1.5～3.5),且群落相似性较高(0.85～0.94),采伐干扰使次生林群落树种沿海拔梯度的变动幅度增大(0.5～6.0),群落相似性下降(0.68～0.91),但次生林群落沿海拔梯度分布仍具有较高连续性.