Molecular systematics and phylogeography of the Plethodon elongatus species group: combining phylogenetic and population genetic methods to investigate species history

Plethodon elongatus and P. stormi (Caudata: Plethodontidae) are Pacific Northwest endemic species which occur in northwestern California and southwestern Oregon. Studies on these salamanders have resulted in differing taxonomic conclusions, but the underlying historical hypotheses, at both inter- and intraspecific levels, have never been examined in a molecular framework. Here, representatives of 81 populations from throughout the range of both taxa are sequenced. Portions of three mitochondrial protein-coding genes (cytochrome b, NADH dehydrogenase subunit 4, and ATPase 6) were sequenced. Four haplotype groups with nonoverlapping geographical ranges were recovered in separate and combined analyses of the data. One clade corresponds to the distribution of P. stormi, while the remaining three comprise P. elongatus. Phylogenetic relationships among haplotype groups differ in separate analyses of the genes but converge on a well-supported topology, with P. elongatus and P. stormi as monophyletic sister taxa, in combined Maximum Parsimony and Maximum Likelihood analyses. Population genetic analyses of mismatch distributions and Tajima's D-statistic are consistent with range expansion for the largest clade within P. elongatus, covering the northern two-thirds of the species range. In contrast, the P. stormi haplotype clade and the P. elongatus clade from the southern third of the species range may have been relatively stable. Morphological boundaries between P. elongatus and P. stormi are largely congruent with mitochondrial DNA breaks and continued treatment as sister taxa is supported. Although mitochondrial DNA haplotype groups may reflect historical separation within P. elongatus, genetic barriers are incongruent with intraspecific patterns of morphological variation.     

Palynomorphs from the Cambrian Series 3, Parahio valley (Spiti), Northwest Himalaya

We present low-diversity acritarch assemblages, including Alliumella baltica, Bavlinella faveolata, Brocholaminaria nigrita, Brocholaminaria sp., Eliasum sp., Leiosphaeridia minutissima, Leiosphaeridia spp., Lophosphaeridium sp., Pterospermella solida, Satka colonialica, Siphonophycus sp., and Synsphaeridium sp., as well as filamentous algae and cryptospore-like microfossils recorded from 45 rock samples around the Oryctocephalus indicus Zone (Cambrian Series 3) in the Cambrian Kunzam La (Parahio) Formation at the Kaltarbo locality in the Parahio valley, Northwest Himalaya. One new species Synsphaeridium parahioense was established. The acritarch assemblages at the basal part of the Cambrian Series 3 in the Kunzam La (Parahio) Formation were dependent on the local marine environment. The new discovery of cryptospore-like microfossils from the Cambrian Kunzam La (Parahio) Formation supports the extensive distribution of possible cryptospores in the Cambrian stratigraphic sequences.     

Applied zooarchaeology and Oregon Coast sea otters (Enhydra lutris)

The sea otter (Enhydra lutris) was nearly driven to extinction on the Pacific Coast in the 19th century due to intensive commercial hunting and the maritime fur trade. Despite successful reintroduction efforts elsewhere in North America, the Oregon sea otter population remains locally extirpated and listed as endangered. Prior study addressed precontact sea otter teeth from Oregon and found they were not significantly different in absolute size from modern California sea otter (Enhydra lutris nereis) teeth, and smaller than modern Alaska sea otter (Enhydra lutris lutris) teeth. These geographic groupings were later confirmed by an ancient DNA study. The conclusion that distinct geographic populations exist based on tooth size was founded on small samples. Larger samples of teeth, as well as new data on humeri and femora, indicate dimensions vary significantly along a latitudinal cline from California to Alaska. Morphometric analyses of ancient animal remains can be used to examine spatial relationships of phenotypic features and inform conservation biology decisions.     

The “Arctic Exception” in the Law of the Sea Convention: A Contribution to Safer Navigation in the Northwest Passage?

This article examines the so-called “Arctic exception,” Article 234 of the 1982 UN Convention on the Law of the Sea. Article 234 is intended to give the coastal state of ice-covered sea areas the necessary powers to prevent, reduce, and control vessel source pollution, which poses a particular risk to the highly sensitive Arctic marine environment. The aim of this article is to present a thorough interpretation of Article 234 in order to eventually evaluate the provision's significance for Arctic navigation, specifically in the Canadian Arctic and the Northwest Passage.     

Spain,the European Union,and Canada: A New Phase in the Unstable Balance in the Northwest Atlantic Fisheries

The past stormy fisheries relations between Canada and the European Union, in particular with Spain, has been replaced by uncertainty in the application of the newly amended Northwest Atlantic Fisheries Convention. These issues are addressed in this article that sheds light on the more peaceful fishing relations between the two leading international actors in this area of the oceans.     

960-2011年西北五省潜在蒸散的时空变化

基于Penman-Monteith模型和Hurst指数模型,分析了我国西北五省1960-2011年潜在蒸散(ET₀)的时空演变特征及其未来趋势,并采用敏感性分析方法定量分析了驱动ET₀变化的主导因素.结果表明:研究期间,西北五省ET₀整体呈下降趋势,降速为-0.72 mm·a^-1,但1993年之后,ET₀逐渐增加;ET₀空间分布存在显著差异,西北五省ET₀平均值为1158 mm 675~2282 mm),最大值出现在新疆的七角井（2282 mm）,低值区主要分布在陕南秦巴山地（<800 mm）.除春季外,其余季节ET₀均呈下降趋势,且在未来趋势分析中,西北五省81.4%的区域ET₀由减少转为增加,在全球变暖背景下,该区暖湿化程度将有所减弱,而新疆中部的ET₀将持续减少.西北五省全年及各季节影响ET₀变化的主导因素主要为风速,但风速在不同季节、不同区域的影响范围有所差异,冬季风速影响范围覆盖整个西北五省,夏季则影响整个新疆及甘肃和青海的西北部.     

滇西北地区优先保护的植物群落类型

确定优先保护的地区和群落类型对生物多样性保护尤为重要.为评价滇西北地区优先保护的植物群落类型,针对植物群落在维持栖息地稳定及生物多样性保护方面的功能,依据科学性、层次性及可操作性等原则,构建了由3个层次6个指标构成的评价指标体系.6个与群落相关的指标分别是:物种多样性、珍稀濒危植物物种种数、保护植物级别、群落稀有性、特有植物物种种数和群落特有性.通过对滇西北地区现有资料的收集整理,共选出有样地数据的群落61个,归入13个植被亚型.根据数据的分布特征,利用等级赋值的方法制定了各个指标的评分标准.运用层次分析法与专家咨询法相结合确定权重,采用综合指数法对各群落及植被亚型进行评价,再进行重分类,划分出一级、二级、三级和一般保护类型.利用ArcGIS9.3软件制作不同保护级别的植被亚型的分布图,划分出优先保护的区域.综合评价划分出一级保护群落4类,二级31类,三级23类,一般3类;一级保护植被亚型1类,二级6类,三级6类.这些优先保护类型中,一级保护类型少量,分布在贡山县西南部和泸水县西南部的高黎贡山;二级保护类型较为集中地分布在研究区西北部高海拔地区各大山系及东南部高山地区;三级保护类型主要分布在研究区东南部海拔较低的区域以及独龙江、怒江、澜沧江和金沙江流域的河谷地段.     

The First Record of the Pterosaur Ichnogenus Purbeckopus in the Late Berriasian (Early Cretaceous) of Northwest Germany

A hypichnium of a manus imprint (preserved as plaster cast) indicates for the first time the presence of the large pterosaur ichnotaxon Purbeckopus cf. pentadactylus Delair, 1963 in the late Berriasian of northwest Germany. It is only the second record of Purbeckopus globally and the first pterosaur track from Germany. It provides evidence of a very large pterosaur (wingspan c. 6 m) in this area and from this time period not yet represented by skeletal remains. When compared with the English type material, the specimen exhibits some differences that are related mostly to different properties of the substrate on which both were left. These include, in the German track, an impression of the metacarpo-phalangeal joint of the wing finger, normally not present in pterosaur tracks. Also interesting is the rather blunt termination of the deeply impressed digits I–III, indicating rather short and blunt claws, which seem more suitable for walking than for grasping or climbing. The specimens of Purbeckopus in England and Germany occur in different environments: the English locality was situated close to a brackish lagoon, while the German site belongs to a limnic-deltaic system at the margin of a large, freshwater lake.     

西北干旱区生态脆弱性时空演变分析

西部大开发政策实施以来,随着社会经济的发展和环境政策的调整,西北干旱区生态环境发生深刻变化。基于西北干旱区生态本底特征,选取土壤、地形、气候并结合夜间灯光数据构建西北干旱区生态脆弱性评价体系,运用空间主成分分析法（SPCA）、地理探测器对西北干旱区2000、2007、2012、2018年生态脆弱性时空演变及驱动力进行分析。结果表明：（1）从西北干旱区生态脆弱性时空演变特征来看,研究区生态脆弱性以重度脆弱性为主;从不同土地利用脆弱性来看,微度脆弱区以草地、林地为主,轻度脆弱区以草地为主,中度脆弱区和重度脆弱区以未利用地为主,18年来研究区生态脆弱性整体保持不变;（2）影响西北干旱区生态脆弱性分异的主导因素包括土壤有机质含量、地形位指数、气温、降水、夜间灯光指数,各因素对生态脆弱性的平均决定力分别为0.63、0.36、0.27、0.26和0.22。（3）基于生态脆弱性监测结果和驱动因素分析,将西北干旱区划分为5个生态功能区：生态核心保护区、生态综合监测区、生态优化关注区、生态恢复治理区、生态潜在治理区,并提出相应管理方案。研究可以为干旱区生态环境保护提供借鉴。