A tree-ring perspective on the extreme wetness of the early 1900’s in the western United States [abstract]

Ring-width indices from 136 sites in the area from northern Montana to southern New Mexico between latitudes 103°W and 111°W were examined to infer periods of anomalous wetness for the years 1700-1964. Sites were grouped into north, central and south regions, and the gross regional tree-ring fluctuations were compared. The results indicate that the period 1905-1917 was unique in the 265-year record for the combined magnitude, duration, and north/south coherence of the growth anomaly of much lesser magnitude occurred in the 1830's-1840's [sic]. Both this and the 1905-1917 anomaly appear from time-series plots to be manifestations of low-frequency growth variations at wave lengths between about 20 and 60 years.

海南岛蕨类植物的分类、区系地理与保育

摘要 "基于形态－地理学方法，通过野外调查，结合大量标本研究，在前人研究的基础上，对海南蕨类植物的分类进行了进一步修订;主要根据蕨类植物的现代地理分布，结合古生物学等有关资料，初步探讨了海南蕨类植物的区系性质与起源;根据IUCN2001年红色名录的等级和标准，对海南濒危蕨类植物的现状进行了初步评估，讨论了海南蕨类植物的受威胁原因，提出了有关保护的对策。主要结果如下： 1. 海南现有蕨类植物56科140属439个种及种下分类群（包括421种、15变种、2亚种和1变型），其中包括1个中国分布新记录和27个海南分布新记录，1新种――海南符藤蕨Teratophyllum hainanense;另有11个名称首次被处理为异名;澄清了海南假瘤蕨Phymatopteris hainanensis和圆顶假瘤蕨P. obtusa的模式问题，为滇桂三相蕨Ataxipteris dianguiensis、海南假瘤蕨P. hainanensis和浅杯鳞盖蕨Microlepia ampla指定了后选模式。 2. 海南蕨类区系具有以下特点：i. 以水龙骨科Polypodiaceae、金星蕨科Thelypteridaceae、铁角蕨科Aspleniaceae、叉蕨科Tectariaceae和观音座莲科Angiopteridaceae为表征科;ii. 明显的热带性质，科的97.5％、属的92.5％、种的83.6％为热带分布成分;iii. 很高的物种多样性与物种密度，但属内种系贫乏;iv. 与中南半岛的联系最为紧密，海南140个蕨类属中有136个与中南半岛共有，两地属的相似性系数达到87.2%;v. 海南蕨类区系就地起源于华夏古陆，起源时间可以追溯至早石炭世以前。 3. 海南439种蕨类（包括421种、15变种、2亚种和1变型）中，183种为常见蕨类，113种属于资料缺乏的种类（DD），47种属于近危（NT），53种属于易危（VU），37种属于濒危（EN），6种属于极危（CR）。海南的受威胁蕨类植物有96种，海南的绝大部分受威胁蕨类植物都生于保护区以内或得到有效保护的林区之内，已初步得到保护。导致海南96种蕨类受威胁的因素，除了植物本身的生物生态学特性和地理分布上的限制外，主要是人类活动的影响，特别是海南森林在上个世纪被大规模砍伐。为了保护这些受威胁植物，应加强保护区和林区的管理，实施就地保护，积极开展迁地保护和人工繁殖。 "

五味子科的系统学研究

本文通过对五味子科及其近缘类群植物的形态性状、叶表皮解剖特征、木材解剖特征、细胞学以及分支系统学研究，发现了一些重要的新性状，提出了新的五味子属的次级划分，阐明了南五味子属与五味子属的属间系统学关系，以及它们与近缘类群间的系统学关系，最后对这两属进行了分类学修订。主要内容包括： 1.形态性状分析 　　我们在查阅大量国内外馆藏标本和野外居群观察的基础上，对五味子科植物及部分近缘类群的形态性状和变异式样进行了详细地比较分析，重新评价了各性状的分类学价值，认为习性、茎有无棱翅、叶有无毛被、花雄蕊群特征及果实和种子形态等性状具有系统学意义，而叶片形状和大小、毛被多少、花被片颜色等特征在种内变化较大，不宜作为种的划分依据，至少不能作为主要的或唯一的依据。 2.叶表皮形态解剖学 　　在光学显微镜和扫描电镜下，分别观察了南五味子属全属11种共92个样品、五味子属全属10种共136个样品和八角属2种共15个样品的叶表皮形态特征。结果发现南五味子属和五味子属植物的叶表皮性状，包括表皮细胞形状、气孔类型、保卫细胞形状及叶表皮细胞表面的角质纹饰、表皮毛的有无等在种内稳定且在种间有明显差异，对研究属内和属间关系有重要系统学意义。 　　在南五味子属中，发现了一个新的分类学性状：叶表皮表面具脊状网纹，该性状支持将南五味子属分为离蕊南五味子亚属Subg. Cosbaea和南五味子亚属Subg. Kadsura，且根据叶表皮形态特征和性状分析，支持将南五味子亚属分为南五味子组Sect. Kadsura和肉蕊组Sect. Sarcocarpon，同时支持R. M. K. Saunders和林祁对某些种的归并处理。 　　在五味子属中发现一新的分类学性状：气孔器外拱盖，表明该属常绿类群的气孔具有双层外拱盖，而落叶类群的气孔具有单层外拱盖。这一性状支持前人将五味子属根据习性和雄蕊群特征划分为两个亚属的观点，这一观点同样得到了包括形态学和分子系统学证据的支持。此外，还发现在全为常绿习性的南五味子属中，气孔都具双层外拱盖，一方面说明五味子属的常绿类群与南五味子属有一定的相似性，亲缘关系密切，这同样得到分子证据的支持;另一方面表明五味子科植物生长习性与气孔器特征有一定相关性。 　　通过比较南五味子属与五味子属以及近缘的八角属叶表皮形态特征，认为这三个属的叶表皮形态特征非常相似，只是南五味子属在叶表皮形态特征上比五味子属和八角属具有更多的复杂或次生性状状态，此外，研究结果不支持将五味子科从八角目中分出而成立五味子目的观点。 3.比较木材解剖学 　　在光学显微镜下观察了南五味子属7种21个样品和五味子属8种16个样品的木材解剖特征，结果表明次生木质部的导管分子类型、导管-射线间纹孔的排列方式、射线类型、射线细胞形状等性状特征在科的水平上很稳定，这些共同特征都支持五味子科是比较自然的类群。在五味子科中发现木材导管单生、具梯状穿孔板、导管壁具梯形排列的纹孔以及木射线异型等原始性状，支持五味子科在被子植物中的原始地位。此外，该科木材还具有单穿孔板导管、导管次生壁具螺纹加厚、具分隔纤维等较为特化的性状状态，这种性状进化水平的异等级现象，使五味子科表现出不同进化水平性状的镶嵌组合。根据木材解剖性状对五味子科进行UPGMA聚类分析，结果显示南五味子属和五味子属在木材解剖特征方面有一定的交叉和重叠，这与分子系统学的结论一致，表明这两个属关系密切，可能起源于共同的祖先。通过比较五味子科与八角科的木材解剖特征，进一步证明两个科的亲缘关系很近，同样不支持将五味子科从八角目中独立出来成立五味子目的观点。 4. 细胞分类学 　　对五味子属铁箍散Schisandra propinqua（Wall.）Baill进行了细胞学研究，首次报道该种植物的染色体核型。核型分析的结果表明染色体数目为2n = 28,核型公式为2n = 2x = 20m+8sm, 染色体相对长度组成2n = 2L+14M2+8M1+4S，核型不对称系数0.59，核型为2B型，未发现次缢痕和随体。通过与该属其它种类的核型进行比较，发现具常绿习性的铁箍散其核型不对称性系数比该属落叶种类高，表明该种在五味子属中处于较进化的地位，这与我们根据该属其它性状得出的结论一致。 5. 分支系统学研究 　　对五味子属33个形态学性状进行了分支系统学研究，得到5棵同等最简约树，树长为53步，一致性指数（CI）= 0.7740, 保留性指数（RI）= 0.7740。在最简约树(MP)的严格一致树中，内类群形成两大支，一支包括所有落叶习性的类群，另一支包括具有常绿习性的类群，两支的支持率都非常高, 在一定程度上能反映五味子属内各种间的系统学关系。根据五味子属分支系统学分析的结果，对该属属下分类系统进行了调整。 　　在补充了包括叶表皮形态解剖学和木材解剖学等新性状的基础上，对五味子科42个形态学性状进行了分支系统学分析，分别计算得到了MP树和邻接树（N-J）。简约分析得到三棵同等最简约树，树长106步，一致性指数（CI）= 0.4910，保留性指数（RI）= 0.7450。严格一致树显示：五味子科分为五个并列的分支，其中南五味子属被分为三支，五味子属被分为两支，虽然这些分支的支持率都不是很高，但是一些种类间的亲缘关系还是得到很好的体现。用距离法建立的N-J树中，将该科分为两大支，五味子属所有落叶种类聚为一支，南五味子属和五味子属具常绿习性的类群聚为一支，这与分子系统学分析的结果一致，但是由于在N-J树上，五味子属两个常绿种与南五味子属构成的分支支持率较低，所以两属之间的关系还尚待讨论。 6. 分类学修订 　　在应用上述性状分析结果及查阅国内外大量标本的基础上，重新修订了南五味子属和五味子属的概念，包括新性状的补充，对两属植物进行了分类学修订。确定了南五味子属目前包括2亚属2组11种;五味子属目前包括2亚属4组10种,指定了Embelia valbrayi H. Léveillé的后选模式，提出一个新等级组。描述了每个种的性状特征、变异情况、地理分布、相关的分类学处理及其与近缘种的关系，并列出所研究的标本，最后讨论了南五味子属和五味子属的系统关系。 　　

Gulf of Mexico tidal creeks serve as sentinel habitats for assessing the impact of coastal development on ecosystem health

A study was conducted, in association with the Alabama and Mississippi National Estuarine Research Reserves (NERRs) in the Gulf of Mexico (GoM) as well as the Georgia, South Carolina, and North Carolina NERRs in the Southeast (SE), to evaluate the impacts of coastal development on tidal creek sentinel habitats, including potential impacts to human health and well-being. Uplands associated with Southeast and Gulf of Mexico tidal creeks, and the salt marshes they drain, are popular locations for building homes, resorts, and recreational facilities because of the high quality of life and mild climate associated with these environments. Tidal creeks form part of the estuarine ecosystem characterized by high biological productivity, great ecological value, complex environmental gradients, and numerous interconnected processes. This research combined a watershed-level study integrating ecological, public health and human dimension attributes with watershed-level land cover data. The approach used for this research was based upon a comparative watershed and ecosystem approach that sampled tidal creek networks draining developed watersheds (e.g., suburban, urban, and industrial) as well as undeveloped sites (Holland et al. 2004, Sanger et al. 2008). The primary objective of this work was to define the relationships between coastal development with its concomitant land cover changes, and non-point source pollution loading and the ecological and human health and wellbeing status of tidal creek ecosystems. Nineteen tidal creek systems, located along the Southeastern United States coast from southern North Carolina to southern Georgia, and five Gulf of Mexico systems from Alabama and Mississippi were sampled during summer (June-August) 2005, 2006 (SE) and 2008 (GoM). Within each system, creeks were divided into two primary segments based upon tidal zoning: intertidal (i.e., shallow, narrow headwater sections) and subtidal (i.e., deeper and wider sections), and watersheds were delineated for each segment. In total, we report findings on 29 intertidal and 24 subtidal creeks. Indicators sampled throughout each creek included water quality (e.g., dissolved oxygen, salinity, nutrients, chlorophyll-a levels), sediment quality (e.g., characteristics, contaminant levels including emerging contaminants), pathogen and viral indicators (e.g., fecal coliform, enterococci, F+ coliphages, F- coliphages), and abundance and tissue contamination of biological resources (e.g., macrobenthic and nektonic communities, shellfish tissue contaminants). Tidal creeks have been identified as a sentinel habitat to assess the impacts of coastal development on estuarine areas in the southeastern US. A conceptual model for tidal creeks in the southeastern US identifies that human alterations (stressors) of upland in a watershed such as increased impervious cover will lead to changes in the physical and chemical environment such as microbial and nutrient pollution (exposures), of a receiving water body which then lead to changes in the living resources (responses). The overall objective of this study is to evaluate the applicability of the current tidal creek classification framework and conceptual model linking tidal creek ecological condition to potential impacts of development and urban growth on ecosystem value and function in the Gulf of Mexico US in collaboration with Gulf of Mexico NERR sites. The conceptual model was validated for the Gulf of Mexico US tidal creeks. The tidal creek classification system developed for the southeastern US could be applied to the Gulf of Mexico tidal creeks; however, some differences were found that warrant further examination. In particular, pollutants appeared to translate further downstream in the Gulf of Mexico US compared to the southeastern US. These differences are likely the result of the morphological and oceanographic differences between the two regions. Tidal creeks appear to serve as sentinel habitats to provide an early warning of the ensuing harm to the larger ecosystem in both the Southeastern and Gulf of Mexico US tidal creeks.