呼伦贝尔沙质草原风蚀坑积沙区的植被分带性

呼伦贝尔沙质草原现代风蚀坑主要包括平缓草地的简单风蚀坑、复合风蚀坑和固定沙丘的简单风蚀坑3种类型。坑后积沙区植被出现明显的分带性,且随风蚀坑及其下风侧积沙体的形态、尺度而发生变化。在平缓草地简单风蚀坑下风侧积沙体平面形态呈顺风向的舌状,由坑口至原生草地,随积沙厚度顺风向减小,依次出现沙蓬、冰草和百里香3个植被带;平缓草地复合风蚀坑后缘形成具有滑落面的大型流动沙丘,在沙丘背风侧顺风向依次出现舌状裸沙带、舌状拂子茅带及两侧的冰草带;固定沙丘风蚀坑坑后积沙呈裸沙形式穿越沙丘原有的山刺玫和小叶锦鸡儿两个灌木带,并在裸沙带外围形成舌状拂子茅带。风蚀坑下风侧积沙区植被的分带性反映了草地植被对风沙活动的响应,即随着坑后积沙体的扩大,草地植被由原生向沙生逆向演替。

西北地区地下水对植被生存演替的作用

在介绍西北地区的气候及水资源的基本特征的基础上 ,分析了植被的分带、生存适应性及演替与地下水的关系 ,并阐述了地下水开采对植被的影响。结果表明 ,植被的分布、生存和演替主要受控于水盐条件。人为活动下 ,这种条件的改变势必影响着植被的生存。最后 ,就如何处理合理用水和植被生存的关系 ,提出了一些建议 ,这对于西北大开发的生态建设有一定的借鉴意义。

黄河源区弯曲河道草甸型植被分布特征

为了认识黄河源区弯曲河流滨河植被的带状分布特征及其演变规律,2015-2016年在黄河源区兰木错曲的河湾凸岸沿中轴线方向展开植被样方调查、植物种鉴定和土体级配特征分析等工作。研究结果表明,兰木错曲河湾凸岸浅水区至河漫滩上,滨河植被普遍具有4个明显的带状或弧状带分布,依次呈现从水生草本植物、湿中生草本植物、中生草本植物至矮生灌木的植被过渡。植被覆盖度由10%增大至100%,地表土壤机械组成由粉土质砾逐渐过渡为粉土质砂、粉土,级配由不均匀过渡至均匀。由灰色关联结果可知,植被覆盖度与土体粘粒含量、粉粒含量和根密度的关联性较强,关联度分别达到0.907、0.900、0.815。

长白山森林植被的生态气候学指标

在全球变化和植被与气候关系的研究中侧重与大尺度、宏观的抽象研究,对小尺度、微观的具体地段植被与气候关系的研究即局地生态气候的研究尚待深入。本文在建立生态气候学指标的基础上,应用桑斯威特(C W Thornthwaite)的方法对长白山森林植被的空间分布进行了定量分析。计算了长白山不同坡向不同高度的温度效率指数。根据30个主要树种的温度效率指数,确定了长白山不同坡向的各植被垂直带的温度效率指数及分布高度。并利用AreGIS8 1软件做长白山1∶1000000的DEM图,得到长白山不同坡向各垂直带植被与温度效率指数的关系图。

南坨植被

坨梁位于太行山中北段,平山县北部,与阜平、五台县交界处,主峰南坨山海拔2281米。这里山高谷深,植被茂密,自然生态保持原始特色,从山谷到山顶植被垂直分带明显。海拔1370米—1500米的沟谷生长有杨、柳、枫、椿等乔木;海拔1500米—1750米是由栎、槭、山杨等组成的落叶阔叶林带;海拔1 750米—1890米是由红桦、白桦、和松组成的混交林带;海拔1890米—2000米为落叶松组成的针叶林带;海拔2000米以上为山地草甸植被。这里植被覆盖率在90％以上,是消暑避夏、科学考察的理想地区。

Vegetation-Climate Relationship and Its Application in the Division of Vegetation Zone in China

Distribution of vegetation is closely coupled with climate; the climate controls distribution of vegetation and the vegetation type reflects regional climates. To reveal vegetation_climate relationships is the foundation for understanding the vegetation distribution and theoretically serving vegetation regionalization. Vegetation regionalization is a theoretical integration of vegetation studies and provides a base for physiogeographical regionalization as well as agriculture and forestry regionalization. Based on a brief historical overview on studies of vegetation_climate relationships and vegetation regionalization conducted in China, we review the principles, bases and major schemes of previous vegetation regionalization and discuss on several contentious boundaries of vegetation zones in the present paper. We proposed that, under the circumstances that the primary vegetation has been destroyed in most parts of China, the division of vegetation zones/regions should be based on the distribution of primary and its secondary vegetation types and climatic indices that delimit distribution of the vegetation types. This not only reveals the closed relationship between vegetation and climate, but also is feasible practically. Although there still are divergence of views on the name and their boundaries of the several vegetation zones, it is commonly accepted that there are eight major vegetation regions in China, i.e. cold temperate needleleaf forest region, temperate needleleaf and broadleaf mixed forest region, warm temperate deciduous broadleaf forest region, subtropical evergreen broadleaf forest region, tropical monsoon forest and rain forest region, temperate steppe region, temperate desert region, and Qinghai_Xizang (Tibetan) Plateau high_cold vegetation region. Analyzing characteristics of vegetation and climate of major vegetation boundaries, we suggested that: 1) Qinling Mountain_Huaihe River line is an important arid/humid climatic, but not a thermal climatic boundary, and thus can not also be regarded as the northern limit of the subtropical vegetation zone; 2) the northern limit of subtropical vegetation zone in China is along the northern coast of the Yangtze River, from Hangzhou Bay, via Taihu Lake, Xuancheng and Tongling in Anhui Province, through by southern slope of the Dabie Mountains, to Wuhan and its west, coinciding with a warmth index ( WI ) value of 130-140 ℃·month; 3) the tropical region is limited in a very small area in southeastern Hainan Island and southern edge of Taiwan Island; and 4) considering a significant difference in climates between the southern and northern parts of the warm temperate zone, we suggested that the warm temperate zone in China is divided into two vegetation regions, deciduous broadleaf woodland region and deciduous and evergreen broadleaf mixed forest region, the Qinling Mountain_Huaihe River line being as their boundary. We also claimed that the zonal vegetation in North China is deciduous broadleaf woodland. Finally, we emphasized the importance of dynamic vegetation regionalization linked to climate changes.

Assessment of the Diversity, Distribution and Uses of Wild Edible Mushrooms in Ekiti State, Nigeria

Lack of information about the available species of mushroom, the distribution along different ecological zones and purposes for which they have been used has hampered their domestication for sustainable production. This study assessed the diversity, distribution and uses of wild edible mushrooms in Ekiti State. The study area was stratified based on vegetation distribution into two zones （rainforest and derived savanna zones）. Pre-tested semi-structured questionnaires were administered to 80 randomly selected respondents for data collection. Descriptive statistical technique of frequency counts and percentages were used to summarize the data. Information from the study revealed that 52.5% and 67.5% of the respondents are above 50 years in the rain forest and the derived savannah vegetation, respectively. About 57.5% and 47.5% of the respondents had at least secondary education in the rainforest and derived savannah vegetation, respectively, while majority of the respondents with over 20 years of collection experience carried out their hunting in free areas outside forest reserve in both ecological zones. Twenty different species of mushroom are collected at different period of the year for consumption. The study recommended that government should checkmate further destruction of the remaining natural forest to ensure continued availability of these mushrooms.

辽西义县组砖城子层孢粉组合时代及古气候记录

在辽西义县鹰窝山地区义县组砖城子层采样,通过对孢粉化石的处理、鉴定和分析,确认该孢粉化石组合为Cicatricosisporites-Protoconiferus组合(无突肋纹孢-原始松柏粉组合),组合当中以裸子植物花粉,尤其是松柏类双气囊花粉占绝对优势,蕨类植物孢子较少,有少量疑似被子植物花粉.孢粉组合时代为早白垩世凡兰吟晚期或欧特里夫期-巴列姆期.应用孢粉植被的概念,依据孢粉谱和孢粉类群的古生态特征,首次对辽西地区义县组砖城子层的植被类型、气候带类型、干湿度类型分别进行了定量划分,并得出演化趋势,结果显示,在辽西义县组砖城子层沉积时期,总体气候温暖湿润,植被类型多样,有针叶林、落叶阔叶林、常绿阔叶林、草丛、灌木等;局部气温变化趋势是从温暖向更温暖、气候从半湿润向湿润方向演化,植被类型始终以针叶林为主,落叶阔叶林、常绿阔叶林、草丛、灌木和一些旱生植物的共存说明可能有垂直分带现象,且气候变化有季节性.值得注意的是,从植被类型的垂直分带现象和气候温暖湿润来综合推断,辽西义县组沉积时期地貌反差可能很大.