Riparian roots through time, space and disturbance

Riparian zones are landscape features adjacent to streams and are widely recognized as important in reducing erosion and filtering groundwater. Few studies directly investigate rooting dynamics of riparian areas, and little information exists concerning riparian root densities, biomass, depth profiles, changes through time, or vulnerability to disturbance. This study examined spatial and temporal patterns in root systems in streamsides influenced by season, hydrologic regime, vegetative composition, and ice storm disturbance in the eastern Adirondacks, New York. Sequential root cores and in-growth cores were collected from June 2000 through August 2001 in a riparian area with minimal ice storm damage adjacent to a third-order stream. Data were used to assess seasonal trends in root biomass and to provide a reference for spatial comparisons. The biomass and surface area of roots collected in the reference site cores were compared with cores collected at nine additional riparian sites differing in degree of canopy damage from the January 1998 ice storm. Average root biomass at the reference site was 1330 g/m², comparable to or greater than values reported for terrestrial and other riparian systems. Root biomass varied seasonally with a maximum root biomass in August, 2000; this result was not repeated the following year after the water table inundated much of the rooting zone in mid-June. Root biomass was spatially variable on a range of scales. Although the maximum root surface area occurred in the upper 10 cm, root biomass peaked at 20–30 cm belowground, unlike observations from most other root studies where the maximum root biomass has been found in the top 10 cm. Areas severely damaged by the ice storm had significantly less root biomass and surface area than areas with low damage. This study demonstrates that root biomass in riparian areas is highly dynamic over time, space, and across disturbance sites. Our findings suggest that the spatial variability in root densities has direct implications for riparian vulnerability to erosion.     

中国云南省四种蟹蛛(蜘蛛目,蟹蛛科)记述

描述了采自中国云南省高黎贡山的4种蟹蛛:小棒绿蟹蛛Oxytate clavulata Tang,Yinet Peng,sp.nov.和中国3新纪录种:不丹绿蟹蛛Oxytate bhutanica Ono,2001,小斜蟹蛛Loxobates minor Ono,2001和南国花叶蛛Synema nangokuOno,2002,其中小斜蟹蛛的雌性为首次发现。小棒绿蟹蛛,新种Oxytate clavulata Tang,Yinet Peng,sp.nov.(图1~5)正模♂(HNU-YHY2601),云南腾冲县上营乡大蒿坪村,2040m,2006-06-04,尹长民、胡佳芳、杨效华采。词源:本种因触肢器的插入器呈小棒状而命名。新种近似于平行绿蟹蛛O.parallela(Simon,1880),但能与后者区别于:1)触肢后侧突末端弯向内侧而后者弯向腹侧;2)插入器基部有一突起而后者没有。分布:中国云南。不丹绿蟹蛛Oxytate bhutanica Ono,2001(图6~15)Oxytate bhutanica Ono,2001:205,figs.1-5.观察标本:1♀,1♂(HNU-YHY0401),界头乡桥头村,1652m,2006-05-17;6♀♀(HNU-YHY0302),界头乡周家坡,1660m,2006-05-16;1♂(HNU-YHY0803),界头乡张家营村,1665m,2006-05-20;1♀,1♂(CAS-YHY1506),腾岳镇宝丰寺,1790m,2006-05-31;1♀(CAS-YHY1703),曲石乡热海,1470m,2006-06-01;1♀(CAS-YHY3801),荷花镇米兰,1400m,2006-06-07。以上标本均由尹长民、胡佳芳和杨效华采自云南省腾冲县。其余观察标本:1♀(HNU-Tang040501),贡山县独龙江乡迪政当村,1841m,2004-10-27~30,唐果采;1♀(HNU-Tang040605),贡山县独龙江乡龙元村白来组,1676m,2004-10-31~11-03,唐果采;2♀♀(CAS-DHK0501201),泸水县片马乡岗房,1780m,2005-05-16,David KAVANAUGH采。分布:不丹、中国(云南)。小斜蟹蛛Loxobates minor Ono,2001(图16~28)Loxobates minor Ono,2001:207,figs.6-8.观察标本:1♀,2♂♂(HNU-David065002);云南腾冲清水镇热海良盈村,1450m,2006-06-01,David KAVANAUGH,Roberta BRETT和董大志采;6♀♀(YHY1707:3♀♀,HNU;3♀♀,CAS);云南腾冲清水镇热海,1470m,2006-06-01,尹长民、胡佳芳、杨效华采;1♂(CAS-YHY2102),腾冲荷花镇朗蒲村,1150m,2006-06-02,胡鹏采。分布:不丹、中国。南国花叶蛛Synema nangoku Ono,2002(图29~33)Synema nangoku Ono,2002:206,figs.13-18.观察标本:1♀,3若蛛(HNU-YHY3202),中国云南腾冲芒棒乡,1300m,2006-06-05,胡鹏采。分布:日本、中国(云南)。     

陕西秦岭拟大萼苔科的2个新记录种

报道陕西秦岭的2个苔类新记录种:红色拟大萼苔[Cephaloziella rubella(Nees) Warnst.]和被刺拟大萼苔(Cephaloziella spinicaulis Douin.)。根据标本对2种植物的形态进行了详细的描述,同时对其地理分布进行了简要说明。     

Lineage diversification and historical demography of a sky island salamander,Plethodon ouachitae,from the Interior Highlands

Sky islands provide ideal opportunities for understanding how climatic changes associated with Pleistocene glacial cycles influenced species distributions, genetic diversification, and demography. The salamander Plethodon ouachitae is largely restricted to high‐elevation, mesic forest on six major mountains in the Ouachita Mountains. Because these mountains are separated by more xeric, low‐elevation valleys, the salamanders appear to be isolated on sky islands where gene flow among populations on different mountains may be restricted. We used DNA sequence data along with ecological niche modelling and coalescent simulations to test several hypotheses related to diversifications in sky island habitats. Our results revealed that P. ouachitae is composed of seven well‐supported lineages structured across six major mountains. The species originated during the Late Pliocene, and lineage diversification occurred during the Middle Pleistocene in a stepping stone fashion with a cyclical pattern of dispersal to a new mountain followed by isolation and divergence. Diversification occurred primarily on an east–west axis, which is likely related to the east–west orientation of the Ouachita Mountains and the more favourable cooler and wetter environmental conditions on north slopes compared to south‐facing slopes and valleys. All non‐genealogical coalescent methods failed to detect significant population expansion in any lineages. Bayesian skyline plots showed relatively stable population sizes over time, but indicated a slight to moderate amount of population growth in all lineages starting approximately 10 000–12 000 years ago. Our results provide new insight into sky island diversifications from a previously unstudied region, and further demonstrate that climatic changes during the Pleistocene had profound effects on lineage diversification and demography, especially in species from environmentally sensitive habitats in montane regions.     

基于染色体计数和ITS序列初步探讨横断山区柴胡属植物(伞形科)的系统发育

横断山区是中国柴胡属Bupleurum植物的分布中心。本文对横断山区6个种2变种进行了染色体记数报道,其中4个种2变种是首次报道。对横断山区的10个种4个变种、中国北方（河北和黑龙江）的3个种的nrDNA ITS进行测序,同时从GenBank里面下载同属的来自非洲和地中海西部的16个nrDNA ITS序列数据,结合染色体数目变化结果,初步探讨了横断山区柴胡属植物的系统发育。结果表明横断山区可能是现代柴胡属植物的频度中心和多样分布中心之一。它们的祖先种可能是非洲北部的木本柴胡属植物B.fruticosum,或者是地中海西部的柴胡属植物,推测是通过中东和高加索扩散而形成的,其中与非洲南部特有种B.mundtii的亲缘关系也较近;染色体基数演化趋势是：8是较原始基数,6和7是次生基数,其染色体异基数变异和多倍化可能是物种形成、进化以及向外扩散的主要方式;在ITS系统发育树中,中国柴胡属植物染色体基数为8的种类聚为一支,染色体基数为6和7的种类聚为了一支,不支持舒璞等（1998）关于中国柴胡属的属下分类系统。结合已有的形态学、细胞学、孢粉学证据和ITS系统发育树,建议窄竹叶柴胡B.marginatum var.stenophyllum独立成种。     

Spatial variation of species diversity across scales in an old-growth temperate forest of China

Species richness and abundance are the two most important diversity variables. Species abundance is additive when aggregated across spatial scale, whereas species richness is non-additive. This study analyzes the effect of spatial scale and site on species abundance and richness in a 25-ha temperate forest plot in the Changbai Mountains, northeastern China. The result shows that species abundance and richness are not only dependent on spatial scales, but also dependent on site. Species abundance responds linearly to changes of spatial scale with no intersection in different sites of the study area. However, although species richness also increases with the increase of spatial scale, there are some intersections for the different sites, suggesting that a species-rich site does not always have a high value if the spatial scale is changed. In all, with respect to additive variables, it is relatively easy to extrapolate them from one spatial scale to another spatial scale, as they and the spatial scale usually form a linear relationship. In contrast, non-additive variables are difficult to extrapolate across spatial scales, because they often respond nonlinearly to spatial scale changes. In order to extrapolate these non-additive variables across spatial scales, it is necessary to estimate the relationships between them and spatial scales. As a result, extrapolation of information among spatial scales may be possible, but very difficult, especially for non-additive variables. Because the 25-ha Changbai plot is very small compared to the extent of the world temperate forests, and the vegetation is a relatively uniform type, more such studies in other ecosystems are needed before theories and generalization about scaling effects can be formulated.     

Representatives of the family Bochianitidae (Ammonoidea) from the Lower Cretaceous of the Crimean Mountains

The heteromorph ammonites of the family Bochianitidae from the Lower Cretaceous of the Crimean Mountains are revised. The validity of the genus Janenschites, separated from the genus Bochianites is confirmed. The species Bochianites neocomiensis (d’Orbigny), B. goubechensis Mandov, B. levis sp. nov. and B. crymensis sp. nov. are described from the Berriasian and the species Janenschites oosteri (Sarasin et Schöndelmayer) and J. incisus sp. nov. are described from the Lower Barremian. The family Bochianitidae first appeared at the beginning of the Berriasian in the southern regions (Africa and the Crimea), and spread to the northern regions of western Europe in the Valanginian-Hauterivian.     

长白山区鸢尾属植物资源及其开发利用

对长白山鸢尾属植物的种类、分布、储量、生境、鉴别及开发利用等方面做了评细地调查研究,为开发长白山区鸢尾属植物资源提供了科学依据。     

罗马尼亚特提斯区的早白垩世粗枝藻化石(英文)

本文对藻类 Seloporella属的系统分类进行了评论。根据 Barattolo等人 ,1992年对该属的评论 ,结合对产自罗马尼亚阿朴塞尼山区 ( Apuseni Mountains) ,早白垩世的 Triploporella neocomiensis Radoicˇ ic′及与己发表的资料进行了对比研究 ,提出了 Seliporella neocomiensis的新组合 ,同时与该化石组合形态非常相似的“Diplopora”john-soni Praturlon,1964进行了对比     

七子花苗期光合日进程及光响应

对七子花苗期光合日进程及光响应进行了研究,结果表明:(1)净光合速率的日进程曲线呈双峰型,胞间CO2浓度的日进程基本与净光合速率相反,中午胞间CO2浓度增高表明净光合速率午间降低主要受非气孔限制因素的影响。暗呼吸速率日进程呈单峰曲线,中午最高。光能利用效率以上午7∶00为最高,中午最低,以后又逐渐上升。(2)净光合速率最适温度为25～30℃,高光合有效辐射和高温下光抑制加剧。(3)29℃下饱和光强为890μmolm 2s 1,表观量子效率为0.0325,光补偿点为44μmolm 2s 1;随着光合有效辐射的增强,气孔阻力减小,但光合有效辐射过高,气孔阻力却有所上升。(4)在29℃的饱和光强下,羧化效率为0.0351,CO2补偿点为173μmolmol 1,低于或高于饱和光强,羧化效率下降,CO2补偿点升高。