封育对云雾山本氏针茅草地群落的影响

以云雾山封育与未封区为对象,采用样线法进行调查,重点分析二者群落特征和地上生物量的变化,以期为退化草地植被恢复提供依据。结果表明:封育后本氏针茅(Stipa bungeana)群落发生较大变化,物种数显著增加、演替差异明显,由未封区的本氏针茅+大针茅(S. gigantea)群落演替为封育后的大针茅+本氏针茅群落;未封区本氏针茅种群的优势地位明显加强,重要值明显大于封育区;封育与未封区群落的相似性系数为0.419;物种丰富度指数和多样性指数(修正的Simpson指数、Shannon-winner指数、Audair和Groff指数)均表现为封育区>未封区,而均匀度指数则相反;封育区地上生物量明显增加,其中禾本科、蔷薇科和杂类草占总生物量的比例均表现为封育>未封区,而菊科则相反。

云雾山本氏针茅群落根系分布特征

为揭示本氏针茅(Stipa bungeana Trin.)群落的生理生态适应机制,采用根系取样器(Φ=9 cm)对宁夏云雾山本氏针茅群落根系分布特征和土壤含水量进行研究。结果表明:本氏针茅群落地下生物量、根长密度、根表面积、比根长均随土壤深度增加而减少,均表现出向表层(0~20 cm)集聚的趋势,且集中分布于0~40 cm土层,最大值均分布在0~20 cm土层,而底层(80~100 cm)最小;所有主要根系分布参数在0~20 cm和20~40 cm土层之间差异显著,以下各层差异不显著;土壤含水量与根生物量和比根长相关性达显著水平(P<0.05),与根表面积、根长密度均呈成正相关;根表面积、根生物量、根长密度和比根长间相关性均达极显著水平(P<0.01)。

黄土高原水土流失区退耕还林(草)的基本思路

朱总理针对 1 998年我国水土流失加剧而致使洪灾造成 2 2 5 1亿元人民币巨大损失的现实 ,于 1 999年 8月提出了“退耕还林 (草 )、封山绿化、个体承包、以粮代赈”的措施 ,为根治黄土高原的水土流失和良化我国的生态环境指明了方向。目前我国黄土高原地区坡耕地水土流失、肥力低下、水源缺乏、灾害频繁。根据黄土高原的生态环境脆弱的具体情况 ,应采取的对策是 :提高思想认识 ;解决好退耕后脱贫 ;推进东西部合作政策 ;保证人均一定的农田 ;实现农林牧业最佳结合 ;提出合理的措施 ;健全保障机制 ;正确处理各种关系

大巴山北坡垂直带土壤特性及系统分类

通过野外考察与室内分析相结合 ,对大巴山北坡不同海拔高度的土壤特性进行研究 ,确定了各剖面的诊断层和诊断特性及其在系统分类中的位置。结果表明大巴山北坡各垂直带土壤在系统分类中可划归 2个土纲的 6个土类 ,系统分类中土壤的分类位置与发生分类位置并不具有简单的一一对应的关系。

秦巴山区中山地小流域土地持续利用模式探讨——以柞水县薛家沟流域为例

在分析薛家沟流域土地利用现状、持续利用条件和限制因素的基础上 ,依据流域立体分异特性 ,提出川平地以粮食种植、坡地以经济果木和防护林为主导的山地林果药菌立体开发的土地利用模式

天山北麓中段土壤侵蚀影响因素及特征分析

通过对天山北麓中段土地类型、河流径流和植被覆盖等土壤侵蚀影响因素的空间分布特征分析认为 :1天山北麓中段主要侵蚀类型为风蚀、水蚀、冻融侵蚀及人为加速侵蚀 ;2侵蚀产沙类型以及产沙强度在空间上具有明显的垂直变化规律 :沙漠以风力侵蚀、高山和亚高山以冻融侵蚀为强烈侵蚀类型 ,普遍存在微度水力侵蚀 ,局部表现为中度甚至强度 ;3水蚀类型有冰川融雪径流侵蚀和降雨径流侵蚀两种方式。天山北麓中段河流产沙时间上主要在每年的 5月初至 8月末 ,且冰川雪水径流产沙要比雨水径流产沙量大 ,空间上则主要位于海拔 80 0～ 1 50 0 m的由第三纪、第四纪地层和黄土堆积所组成的中、低山丘陵地

松果采摘对长白山阔叶红松林生态系统健康的影响

This paper illustrated the relationships between P. koraiensis and animal,and discussed the effect of cones picking on quantity and structure of animal, P. koraiensis regeneration,biomass,services,structure and succession,and nutrient cycle of the ecosystem.It showed that cones picking has damaged the integrity and function of ecosystem health in term of the concepts and characteristics of ecosystem health.The paper was aiming at the strategies to resolve the relationships between cones picking and ecosystem health maintaining in order to give scientific foundations for protection and management of broad-leaved P.koraiensis forest in Changbai Mountain.

土壤水分状况对长白山阔叶红松林主要树种叶片生理生态特性的影响

Potted seadlings of Pinus koraiensis , Fraxinus mandshurica,Juglans mandshurica,Tilia amurensis, and Quercus mongolica ,which are five dominant species in the Korean pine broadleaf forest at Changbai mountain,were grown in different soil moistures.We designed three soil moisture scenarios:85%～100%(high water,CK),65%～85% (medium water,MW) and 45%～65% (low water,LW) of field water holding capacity.The results show that characteristics of typical drought resistance on the leaves are significantly developed.The net photosynthetic rate and water use efficiency of F. mandshurica were higher compared with CK at MW.The net photosynthetic rate and water use efficiency of other 4 tree species at CK were lower than those at MW and LW.The transpiration rate of 5 tree species responses differently to various soil water status.

Impacts of the Wenchuan Earthquake on the Giant Panda Nature Reserves in China

Ministry of Science and Technology of China [2008BAK47B02, 2008BAC44B04, 2008BAK50B06, 2008BAC43B01, 2006BAC08B06]

中国云南轿子雪山自然保护区昆虫资源与生物多样性调查及齿颚卷象科Byctiscini族分类研究（鞘翅目，齿颚卷象科

本论文由两个单元组成，第一部分主要对中国云南轿子雪山自然保护区的昆虫资源分布、物种组成及生物多样性变化做了系统的研究探讨。第二部分是对中国齿颚卷叶象甲科(Rhynchitidae)的绿卷象族的分类系统及生物学进行了初步探讨。轿子雪山是距离昆明最近的自然保护区，并是少数著名的低纬度高海拔雪山之一。轿子雪山自然保护区的生态平衡影响着整个昆明地区的生态环境。但是对于此保护区的生物资源及多样性方面研究至今仍缺乏。作者于2006年8月至2007年8月对云南轿子雪山自然保护区昆虫资源进行了进一步摸底调查，并以地表甲虫为主要研究对象对其物种组成及生物多样性季节变化进行了连续跟踪调查。调查结果如下：1，共获得昆虫标本3725头，分别隶属于14目76科385种。经物种鉴定及对记录资料的进一步整理，得到轿子雪山自然保护区昆虫名录12目72科327种。2，通过对4种典型微环境样地(草地、灌丛、林地以及农田生态系统）的三次跟踪连续调查，共获得标本2451头，分别隶属于24科。其中步甲科(Carabidae)为优势类群，占总数的62.10%；隐翅虫科(Staphylinidae)其次，占12.77% 。可能由于海拔、气温等因素影响，该地区昆虫活动高峰期较短。3，通过对4种典型微生态环境中地表甲虫的生物多样性的比较，表明不同生境内甲虫的多样性指数存在动态变化，在不同生境片区内甲虫存在迁移活动，甲虫多在灌丛中越冬，并随季节及食物源迁移。卷叶象甲绿卷象族(Byctiscini)隶属于鞘翅目(Coleoptera)齿颚卷象科(Rhynchitidae)。以其独特的繁育后代方式——筑造多叶摇篮而闻名。其主要危害杨、苹果、梨、桦、盐肤木等许多重要经济树木。本文根据对文献资料的归纳整理和对现有昆虫标本的检视，对中国齿鄂卷象科(Rhynchitidae)的绿卷象族昆虫进行了较详细的分类系统学研究。共记述了绿卷象族卷叶象甲5属(Byctiscus、Aspidobyctiscus、Byctiscidius、Listrobyctiscus、Baikovius)43种，其中包括1中国新纪录种(Byctiscu regularis)。作者对本族昆虫的生物学及地理分布做了概括性描述，结果显示此族昆虫以东洋区为多数(48.84%)，古北区其次(34.88%)，东洋-古北共有种则占9.30%。此外，根据文献记述及标本检视，纠正一处物种记录错误，并针对部分物种编写了检索表。

Palaeoenvironmental changes from pollen record in deep sea core PC-1 from northern Okinawa Trough, East China Sea during the past 24 ka

A pollen record of core PC-1 from the northern Okinawa Trough, East China Sea (ECS), provides information on vegetation and climate changes since 24 cal. kaBP. A total of 103 samples were palynologically analyzed at 8 cm intervals with a time resolution of 230 a. Four pollen zones are recognized: zone I (812-715 cm, 24.2-21.1 cal. kaBP), zone II (715-451 cm, 21.1-15.2 cal. kaBP), zone III (451-251 cm, 15.2-10.8 cal. kaBP), zone IV (251-0 cm, 10.8-0.3 cal. kaBP), corresponding to Late MIS 3, Last Glacial Maximum (LGM), deglaciation and Holocene, respectively. The LGM is characterized by the dominance of herbs, mainly Artemisia, and high pollen influx, implying an open vegetation on the exposed continental shelf and a cool and dry climate. The deglaciation is a climate warming stage with Pinus percentage increased and Artemisia percentage decreased and a rapid sea-level rise. The Holocene is characterized by predominance of tree pollen with rapid increase in Castanea-Castanopsis indicating the development of mixed evergreen and deciduous broad-leaved forest and a warm, humid climate. Low pollen influx during the Holocene probably implies submergence of the continental shelf and retreat of the pollen source area. The vegetation indicated by pollen assemblage found in this upper zone is consistent with the present vegetation found in Kyushu, Japan. Originating from the humid mountain area of North Luzon of the Philippines, Tasmania and New Zealand, Phyllocladus with sporadic occurrence throughout PC-1 core probably suggests the influence of Palaeo-Kuroshio Current or intense summer monsoon. The observed changes in Pinus and Herbs percentage indicate fluctuations of the sea level, and high Pinus percentage corresponds to high sea level. Spectrum analysis of the pollen percentage record reveals many millennial-scale periodicities, such as periodicities of 6.8, 3.85 2.2, 1.6 ka.

Fine-grained Pleistocene deepwater turbidite channel system on the slope of Qiongdongnan Basin, northern South China Sea

Recently, as oil exploitation has become focused on deepwater slope areas. more multi-channel high resolution 2D and 3D seismic data were acquired in the deepwater part of the Qiongdongnan Basin, northern South China Sea. Based on 3D seismic data and coherence time slice, RMS and 3D visualization, a series of deepwater channels were recognized on the slope that probably developed in the late Quaternary period. These channels trend SW-NE to W-E and show bifurcations, levees, meander loops and avulsions. High Amplitude Reflections (HARs), typical for channel-levee complexes, are of only minor importance and were observed in one of the channel systems. Most of the detected channels are characterized by low-amplitude reflections, and so are different from the typical coarse-grained turbidite channels that had been discovered worldwide. The absence of well data in the study area made it difficult to determine the age and lithology of these channels. Using a neighboring drill hole and published data about such depositional systems worldwide, the lithology of these channels is likely to be dominated by mudstones with interbedded thin sandstones. These channels are formed by turbidity currents originated from the little scale mountain river of mid-Vietnam in SW direction and were probably accompanied by a relative sea level drop in the last glacial age. These channels discovered on the northern South China Sea slope are likely to be fine-grained, mud-dominant and low N:G deposits in a deepwater paleogeographic setting. (C) 2009 Elsevier Ltd. All rights reserved.

No C_4 Plants Found at the Haibei Alpine Meadow Ecosystem Research Station in Qinghai, China: Evidence from Stable Carbon Isotope Studies

Using the measurement of stable carbon isotopes in leaves as a tool to investigate photosyn-thetic pathway of 102 plant species grown at an alpine meadow ecosystem, at the foot of the Qilian Mountain, Qinghai, China. The results indicate that the δ~(3)C values of plants have a narrow range from -28.24‰ to -24.84‰, which means that none of the species examined belongs to C_4 and crassulaceous acid metabolism (CAM) photosynthetic pathway and all of these species perform photosynthesis through the C_3 pathway. This is likely due to a long-term adaptation to environments at the alpine meadow ecosystem.

Potential refugium on the Qinghai-Tibet Plateau revealed by the chloroplast DNA phylogeography of the alpine species Metagentiana striata (Gentianaceae)

Metagentiana striata is an alpine annual herbaceous plant endemic to the east of the Qinghai-Tibet (Q-T) Plateau and adjacent areas. The phylogeography of M. striata was studied by sequencing the chloroplast DNA (cpDNA) trnS-trnG intergenic spacer. Ten haplotypes were identified from an investigation of 232 individuals of M. striata from 14 populations covering the entire geographical range of this species. The level of differentiation amongst populations was very high (G(ST) = 0.746; N-ST = 0.774) and a significant phylogeographical structure was observed (P < 0.05). An analysis of molecular variance found a high variation amongst populations (76%), with F-ST = 0.762 (highly significant, P < 0.001), indicating that little gene flow occurred amongst the different regions; this was explained by the isolation of populations by high mountains along the Q-T Plateau and adjacent areas (N-m = 0.156). Only one ancestral haplotype (A) was common and widespread throughout the distributional range of M. striata. The populations of the Hengduan Mountains region of the south-eastern Q-T Plateau showed high diversity and uniqueness of haplotypes. It is suggested that this region was the potential refugium of M. striata during the Quaternary glaciation, and that interglacial and postglacial range expansion occurred from this refugium. This scenario was in good agreement with the results of nested clade analysis, which inferred that the current spatial distribution of cpDNA haplotypes and populations resulted from range expansion, together with past allopatric fragmentation events. (c) 2008 The Linnean Society of London.