Molecular phylogeny of Solms-laubachia (Brassicaceae) s.l., based on multiple nuclear and plastid DNA sequences, and its biogeographic implications

The Hengduan Mountains region of south-west China is a noted biodiversity,hotspot, but the geographic origins and historical assembly of its rich endemic flora, including the sky-island species of Solms-laubachia Muschl. (Brassicaceae), have been little studied. Previous molecular studies on the phylogeny of Solms-laubachia showed it to be paraphyletic, leading to considerable expansion not only of its taxonomic limits, but also its geographic range, with the inclusion of taxa from outside the Hengduan region. However, these studies provided little resolution of interspecific relationships, preventing inferences about historical biogeography within the clade. In the present study, new sequence data from two nuclear genes (LEAFY and G3pdh) and two chloroplast intergenic spacers (petN-psbM and psbM-trnD) were combined with existing markers to increase phylogenetic signals. Phaeonychium villosum (Maxim.) Al-Shehbaz was found to be nested within Solms-laubachia s.l. In general, phylogenetic relationships appear to be a good predictor of geography, with the Hengduan Mountain endemics embedded in a paraphyletic grade of species from the western Himalayas and central Asia, but they also imply morphological homoplasy. Incongruence was detected between the nuclear and chloroplast gene trees, perhaps resulting from incomplete lineage sorting of ancestral polymorphisms. The crown age of Solms-laubachia s.l. was estimated to be approximately 1.42-3.68 mya, using Bayesian relaxed molecular clock analysis. Historical biogeographic analysis using a parametric dispersal-extinction-cladogenesis model inferred central Asia and the western Himalayas as most probable ancestral range of Solms-laubachia s.l., and estimated higher rates of eastward expansion than westward during the diversification of descendant lineages. In summary, our results suggest that Solms-laubachia s.l. originated during the Pliocene in central Asia, and subsequently migrated eastward into the Hengduan Mountains, colonizing sky-island, alpine scree-slope habitats that may have provided novel ecological opportunity and accelerated speciation, ultimately establishing this region as the present center of diversity of the genus.     

大兴安岭呼中林区火烧迹地粗木质残体特征

对大兴安岭呼中林区不同年份火烧迹地的粗木质残体特征进行了研究.结果表明：呼中林区火烧迹地粗木质残体贮量在24.87～180.98 m³·hm^-2,其中倒木和枯立木分别为6.03～93.91 m³·hm^-2和15.29～138.37 m³·hm^-2,且不同年份火烧迹地之间差异显著;倒木、枯立木所占比例分别为24.26％～86.00％和14.01％～75.4％,且不同年份火烧迹地之间差异显著;倒木和枯立木的优势径级分别为2.50～20 cm和1.50～15 m, 优势长度分别为2.50～15 cm和5～20 m;随着火烧迹地的恢复,粗木质残体贮量的动态变化不明显.粗木质残体特征与火前林分条件和火烧强度密切相关.     

Seasonal changes in the ranging area of Brown-eared pheasant and its affecting factors in Huanglong Mountains, Shaanxi Province

A study on the seasonal changes in the ranging area of Brown-eared pheasant and its affecting factors was conducted in the Huanglongshan Nature Reserve, Huanglong County, Shaanxi Province, China, from March 2006 to January 2007. Forty used sites and forty random plots were selected along 8–9 transects crossing the study area. Fifteen factors related to the changes of altitude were measured in each site. The results showed that the altitude of home range of Brown-eared pheasant varied with seasons: the highest home range was found in summer, and the lowest one was found in winter, while the home range in autumn was higher than that in spring. According to the frequency of occurrences of Brown-eared pheasant in different seasons, we found that its home range occurred mainly at an altitude below 1400 m in spring, above 1500 m in summer, between 1200 m and 1500 m in autumn and below 1300 m in winter. The possible reason that Brown-eared pheasants preferred to live at lower altitude in spring was to have access to water sources and the abundance of food, correlated to the slope locations, number of trees and number of shrubs; in summer, they tended to appear at highest altitude, and the average height of shrubs, average height of grasses, sheltering class and distance to edge of woods, and human disturbance were affecting factors; in autumn, they appeared at higher altitude which was correlated with the covers of trees, shrubs and grasses, and ultimately related to the abundance of food; in winter, they lived at lowest altitude, which was correlated to the distance from the edge of woods, cover of trees and sheltering class, and ultimately related to the abundance of food and shelter.     

Potential pharmaceutical resources of the Qinling Mountain in central China:medicinal fungi

The present investigation on fungal diversity shows that there were rich fungal resources of up to 196 species,belonging to 41 families and 90 genera,in the Qinling Mountainous Range of central China.The dominant families were Polyporaceae,Russulaceae,Tricholomatacea and Lycoperdaceae,which comprised 107 species,54.59% of the total species.The dominant genera were Russula, Lactarius, Trametes, Phellinus, Coprinus,Lycoperdon,Suillu,and Calvatia,which consisted of 59 species,30.09% of the total species.According to the geographical characteristics,the genera were grouped into:cosmopolitan element (74.98%),pantropical element (3.57%),tropical element (1.02%) and north temperate element (21.43%),with the cosmopolitan element constituting the majority.Among these,the cosmopolitan and North Temperate Zone were characteristic of this region.Based on relevant literature review,the primary pharmaceutical action of the medicinal fungi in Qinling Mountain can be classified as follows:anti-cancer,anti-bacteria,anti-inflammation,relief of muscle rigidity and activation of collaterals,hemostasis,immunological regulation,as well as nourishing the stomach and tonification which means enhancing the body system.     

不同坡向高寒退化草地狼毒株高和枝条数的权衡关系

权衡关系是生活史对策理论的基础, 株高和枝条数的权衡关系对理解植物在不同生境下的表型可塑性有重要意义。该研究选择祁连山北坡高寒退化草地, 利用ArcGIS建立研究区域的数字高程模型(DEM), 并提取样地坡向数据, 采用广义相加模型(GAM)与偏相关分析相结合的方法, 分析了不同坡向影响下狼毒(Stellera chamaejasme)种群株高和枝条数的关系。结果表明: 随着坡向由北坡转向东坡、南坡、西坡, 草地群落地上生物量和盖度呈“减小—增大—减小”的变化趋势, 群落高度则先增大后减小; 坡向是影响狼毒株高和枝条数空间分异的主要地形因子; 随着坡向由北、东转向西、南, 狼毒种群株高呈下降趋势, 而枝条数呈上升趋势, 二者表现出此消彼长的权衡关系, 狼毒植株比叶面积先增大后减小。不同坡向狼毒株高和枝条数的权衡关系, 反映了异质生境中资源多重竞争下狼毒生物量分配机制和提高种群适应性的种群更新策略。     

The upper Shemshak Formation (Toarcian–Aalenian) of the Eastern Alborz (Iran): Biota and palaeoenvironments during a transgressive–regressive cycle

The siliciclastic, up to 4,000 m thick Upper Triassic–Bajocian Shemshak Formation is widespread across the Iran Plate, especially in the Alborz Mountains of northern Iran. In contrast to its lower, generally non-marine part, the upper part is marine. Based on the Tazareh section of the eastern Alborz, an integrated analysis of this marine interval is presented. The 1,700 m thick marine sedimentary succession records a gradual deepening from inner to mid and outer shelf environments from the Middle Toarcian to early Late Aalenian. During the Late Aalenian–Early Bajocian, the trend was reversed and infilling of the basin by a large delta system occurred. This general facies development reflects a nearly symmetrical transgressive–regressive (T–R) megacycle, terminated by the inter-regional mid-Cimmerian tectonic event. A renewed transgression in the early Late Bajocian initiated a subsequent sedimentary megacycle. The bioturbated mid and outer shelf sediments contain a low to moderately diverse benthic fauna dominated by deep burrowing bivalves, often preserved in the growth position. A hierarchy of four orders of sedimentary cycles can be recognized (parasequences, parasequence sets, unconformity-bounded third-order depositional sequences, and the 13 ma long second-order T–R megacycle). A regional correlation with the Jajarm area (200 km to the east) shows a very similar temporal facies pattern of the upper Shemshak Formation. The eastern Alborz T–R cycle is completely out-of-phase with other (eustatic) sea-level curves, suggesting regional tectonic control. Rough estimates of subsidence rates give an average value of 126 m/ma. However, much higher values for the Aalenian (230 m/ma), particularly the Late Aalenian (700 m/ma), indicate a distinct increase in subsidence rate towards the Early Bajocian mid-Cimmerian tectonic event. These high subsidence rates suggest that the sediments of the Shemshak Formation of the eastern Alborz formed in a (young) rift basin.     

Associations among spring-dependent aquatic assemblages and environmental and land use gradients in a Mojave Desert mountain range

In many arid landscapes, springs provide the only reliable source of water. Accordingly, both native species and human land uses, including diversion of water, livestock grazing, and recreation, tend to concentrate around springs and spring‐fed riparian areas. We examined whether species richness and composition of aquatic macroinvertebrates at 45 springs in the Spring Mountains, an isolated mountain range in the eastern Mojave Desert (Nevada, USA), could be predicted using readily measured environmental gradients and estimates of disturbance intensity. The Spring Mountains is a focus of regional conservation planning, and managers are charged with prioritizing its springs for conservation and rehabilitation. Our results suggested that species richness of aquatic macroinvertebrates in the Spring Mountains system may be greatest at intermediate levels of natural and human disturbance. Discharge and springbrook length appeared to be only weakly correlated with species richness, whereas neither elevation, nor water temperature, nor electrical conductance was significantly associated with species richness. Nestedness analyses demonstrated that species present in relatively depauperate locations tended to be subsets of the species present in locations that were richer in species, but that pattern did not appear to be driven by either disturbance intensity or by the environmental variables we measured. Disturbance intensity was not associated with the extent to which species presences and absences were predictable. Although our results should not be interpreted to mean that major environmental gradients and disturbance intensity have no effect on distributional patterns of aquatic invertebrates in the Spring Mountains, the ability of these variables to serve as predictors of species richness and composition may be relatively low. Springs and other wetlands in arid landscapes are characterized by isolation and unpredictable disturbances, and faunal responses to environmental gradients may tend to be individualistic and taxon‐specific.     

Plant Functional Group Classification of Herbaceous Species in Quercus wutaishanica Communities in the Taiyue Mountains,Shanxi Province of China

Quercus wutaishanica is warm temperate deciduous broad leaved forest region one of the typical vegetation types. Qwutaishanica vegetation types as a representative of Shanxi, is the main part of shanxi forest. Past research focuses on the subject of Qwutaishanica results, the study of the herb layer seldom reported. The understory layer dominant species of Qwutaishanica community on Qiliyu of Taiyue Moutains, whose abundances clearly vary along environmental(altitudinal) gradients.Herbaceous plants highly responsive to changes in environmental conditions that reflect the dynamic relations between vegetation and environment. In this paper, using the method of sample, investigated the community of Qwutaishanica on Qiliyu of Taiyue Moutains, Shanxi. We used the results of this investigation to calculate species importance values and frequency, which were used to identify 27 dominant species in herbages. χ2 tests, together with association coefficient and percentage cooccurrence, were used to measure interspecific associations of the dominant species of herbaceous. Plant functional types (PFTS) were defined according to interspecific associations and cluster analysis of the dominant species. In studies of forest understory plant assemblages, designating PFTs according to dominant herbaceous species is feasible. Dominant herbaceous species formed seven PFTs: each with its unique spatial distribution and morphological characteristics, are identifiedⅠ.amphigenous Ⅱ.pelouse edge Ⅲ.wet sparse Ⅳ.gap drought resistant Ⅴ.hill edge Ⅵ.alpine Ⅶ.dank. Plant functional types(PFTs) of herbaceous plants varies with altitude gradients, which reflect the relationship between Qwutaishanica and environment well.     

新疆天山一号冰川地区十种藓类植物叶尖的微形态观察

在光学显微镜和扫描电镜下,对新疆天山一号冰川地区生长的10种藓类植物的叶尖（毛尖）的形态、齿（刺毛）、疣、角质层纹饰等微结构进行观察,其中电镜观察结果均为首次报道。结果表明：10种藓类植物叶尖的顶尖细胞和边缘细胞大部分都是透明的,并且细胞壁厚,细胞腔大;而叶尖边缘内卷、粗糙,细胞壁厚,干时细胞壁上下或侧面凹陷,其上有较多的小孔,这些都是明显耐旱特征,有利于水分的吸收及抵御长期寒冷、反射太阳辐射对其伤害,叶尖的类型对苔藓植物科、属级的分类意义不大,但其微形态如叶尖细胞及边缘细胞的形状、数目、细胞壁的凹陷程度以及其上角质层纹饰、乳突的微形态在同属的不同种之间存在明显差异,对于属下种间的鉴定具有一定的分类学价值。     

Population structure and spatial pattern of predominant tree species in a pine–oak mosaic mixed forest in the Qinling Mountains,China

This study investigated a typical pine-oak mosaic mixed forest in the Qinling Mountains, China. In the sample plot, the population structure and spatial distribution of the stems were analyzed for the predominant species, to identify the mechanisms of species coexistence and successional trends of the forest. The population structures of all species were bimodally distributed, with young trees (DBH <1 cm) more abundant than older trees. The population structures of Quercus aliena var. acuteserrata was bimodal and rather continuous. However, Pinus tabuliformis and Pinus armandii were discontinuously bimodal, with distinct size deficiencies. Q. aliena var. acuteserrata trees were clumped throughout the plot, although those of P. tabuliformis and P. armandii were clumped at small scales. Notable negative spatial associations between Q. aliena var. acuteserrata and P. tabuliformis were found at almost scales. P. armandii and Q. aliena var. acuteserrata were negatively spatially associated at small scales but positively associated at large scales. Our findings suggest that interspecific competition gradually develops among the predominant tree species. The dynamics of the pine-oak mosaic mixed forest formed a mosaic distribution of uniformly mixed types, with the slow infiltration of Q. aliena var. acuteserrata populations that would eventually establish a pure stand.