天山中部北麓丘陵地带土壤发生特性与系统分类

通过样地调查与土壤理化性质分析相结合对天山中部北麓丘陵地带的土壤特性进行研究,确定各剖面的诊断层和诊断特性及其在系统分类中的位置。结果表明天山中部北麓丘陵地带在系统分类中可划归为3个土纲4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。     

秦岭北麓生态承载力定量评价研究

基于生态承载力理论,计算和分析了秦岭北麓的生态承载力状况,结果表明:秦岭北麓的生态弹性指数大于50,生态系统具有中等的自我维持与自我调节能力;水资源与土地资源均具有较高的承载能力,但土地资源的承载能力更具优势,承载指数大于70,水资源的承载指数则小于70;从资源的承载压力度来看,土地资源的承载压力比较小,水资源的承载压力则非常大,已超负荷。11个区县中,最低的水承载压力度为2.84,最高的已达到33.89的强压水平,水资源已成为社会经济发展的“瓶颈”。     

太行山低山丘陵区7种典型植物水分利用特征

 为准确评价植物对环境的适应性,以太行山低山丘陵区的7种典型植物为对象,通过测定植物蒸腾速率、光合速率以及水分利用效率等指标,研究不同植物的水分利用特征。结果表明:1)在所研究的7种植物中,火炬树、侧柏、刺槐、荆条和酸枣5种植物的蒸腾速率日变化都属于单峰型;栓皮栎和黄连木为双峰型,双峰型主要与植物的"午休"现象有关,是植物对高温、干旱环境胁迫的主动适应;2)植物之间的水分利用效率有较大的差异,刺槐具有最高的水分利用效率;水分利用效率日均值排序为刺槐>酸枣>栓皮栎>黄连木>荆条>火炬树>侧柏,蒸腾耗水量排序为栓皮栎>火炬树>侧柏>黄连木>刺槐>荆条>酸枣;3)根据蒸腾耗水量和水分利用效率,测试植物可以分为3种类型,栓皮栎和酸枣属于高蒸腾耗水量和高水分利用效率类型,侧柏属于低蒸腾耗水量和低水分利用效率类型,刺槐则属于低蒸腾耗水量和高水分利用效率类型,具有最大的水分竞争优势。     

燕山南麓夏季降水对东亚夏季风变化的响应

利用燕山南麓1951-2005年夏季降水资料和NCEP/NCAR高度场、风场资料,采用趋势分析、小波变换、突变检验等方法,对燕山南麓夏季降水规律和东亚夏季风变化进行了分析。结果发现:(1)燕山南麓夏季降水从1980年以来呈减少趋势,在1996年发生了突变,近年减少更加显著。线性减少趋势显著,平均每10 a减少29mm。(2)燕山南麓夏季降水存在10 a的变化周期,东亚夏季风存在11 a的变化周期,二者变化周期基本一致。降水的10 a周期显著,东亚夏季风11 a周期不太显著。(3)强夏季风年,蒙古地区低气压显著降低,蒙古上空低槽活动频繁,极涡明显变弱,燕山南麓夏季降水偏多。弱夏季风年,蒙古地区低气压明显减弱,蒙古上空低槽活动较少,极涡显著加深,燕山南麓夏季降水偏少。(4)燕山南麓夏季降水减少是对东亚夏季风减弱和对应的中高度大气纬环流变化的响应。     

Rediscovery of a diploid cytotype of Dasypyrum breviaristatum in Morocco

The chromosome numbers of a total of 273 Dasypyrumbreviaristatum plants sampled from 20 Moroccan and one Greek naturalpopulations were examined. 270 plants from all of the populations weretetraploids. Among them, 223 were eu-tetraploids with 28 chromosomes and 47 wereaneuploids with 25, 27 and 29 chromosomes. Besides, three plants were found tobe diploids among 16 plants from a population in the Moyen Atlas Mountains ofMorocco. This is the second report of a diploid cytotype ofD. breviaristatum since the firstcommunication in 1957. Morphologically, the diploids were similar to but smallerthan the tetraploids in plant height, spike length, spikelet number and leafepidermis cell size. However, it was not possible to distinguish between the twocytotypes based on those morphological characteristics alone. A distinctdifference was found between the two cytotypes only in the number of trichomeson the leaf surfaces. The karyotype of the diploid cytotype consisted of a pairof SAT-chromosomes, five pairs of metacentric and a pair of submetacentricchromosomes. Based on the similarity in karyotype and in plant morphologybetween the two cytotypes of D.breviaristatum, we suggest that the diploid cytotype is themost probable candidate for the ancestral form of the tetraploid cytotype.     

Visible and Near-Infrared Reflectance Spectroscopy for Assessment of Soil Properties in the Caucasus Mountains,Azerbaijan

ABSTRACT

This study aimed to predict soil properties using visible–near infrared (VIS-NIR) spectroscopy combined with partial least square regression (PLSR) modeling. Special emphasis was given to evaluating effect of pre-processing methods on prediction accuracy and important wavelengths. A total of 114 samples were collected and involved in chemical and spectral analyzes. PLSR model of each soil property was calibrated for all pre-processing methods using all samples, and leave-one-out cross-validation was used to make comparisons between them. Then, PLSR model of each best pre-processing method was calibrated using a 75% of all samples and correspondingly validated with the remaining a 25%. Model accuracy was evaluated based on coef?cient of determination (R²), root mean-squared errors (RMSE), and residual prediction deviations (RPD). The high correlation coefficients were found between the tested soil properties and reflectance spectra. The pre-processing methods considerably improved prediction accuracy and filtering methods outperformed linearization methods, and the latter outperformed normalization methods. The performance of cross-validation, calibration and independent validation was similar. An excellent prediction (RPD>2.5) model was obtained for soil organic carbon (SOC) and calcium-carbonate (CaCO₃), good quantitative (2.0< RPD<2.5) prediction for sand, silt, and clay, fair prediction (1.4< RPD<1.8) for pH, and poor prediction (1.0< RPD<1.4) for hygroscopic water content (WC). Important wavelengths varied depending on soil property, but some wavelengths were common. This study can be a precursor to building a pioneering soil spectral database, calibrating satellite data, and hyperspectral image mapping of soils as well as digital soil mapping, environmental, and erosion modeling in the Caucasus Mountains.     

东祁连山高寒草地植物群落二维极点排序

利用极点排序对东祁连山高寒草地植物群落进行了分析,并通过Simpson生态优势度指标对植物群落优势度进行了测定。结果表明,(1)在不同的海拔区域内,影响植物群落分布的主要环境因子不同。根据影响植物群落分布的环境因子的变化情况,可将研究地区划分为3个地段,即较低海拔地段(2710~2930m),水分条件对植物群落的分布影响较为明显;中海拔地段(2930~2960m),植物群落的分布主要受水,热组合状况的影响;而在较高海拔地段(2960~3080m),温度条件成为限制植物群落分布的主要因素。(2)群落生态优势度与群落内植物种群数呈负相关,海拔梯度通过影响群落内的种群组成而影响群落生态优势度。不同种群生态优势度的差异则反映了群落对放牧干扰的生态响应,随退化程度的加大,种群组成由抗性弱的物种向抗性强的物种逐渐过渡。     

土壤物理性质对秦岭松栎林建群种形态及物种多样性的影响

为了揭示土壤物理性质对秦岭油松-锐齿槲栎混交林建群种形态及物种多样性的影响,在秦岭中段松栎林集中分布的区域设置15个调查样地,运用相关分析和典范对应分析(CCA)探讨了林地土壤物理特性(容重、孔隙度、持水量)与建群种形态特征、群落物种分布及α-多样性指数的关系。结果显示：①非毛管孔隙度与油松和锐齿槲栎株数呈显著负相关、与锐齿槲栎高度及其冠幅面积呈显著正相关,总孔隙度与油松株数呈显著负相关。②容重与Patrick丰富度指数、Simpson多样性指数及Shannon-Wiener多样性指数均呈显著正相关,毛管持水量与Pielou均匀度指数呈显著负相关。③CCA排序表明,容重、最大持水量和毛管持水量是决定该群落物种分布的主导性因子,大多数草本趋向分布于容重较大且持水量较低的区域。④群落不同层次的多样性指数沿着容重变化在CCA排序图中形成界限明显的4个分布区,容重上升促进草本层多样性,毛管持水量上升促进乔木层多样性,群落整体的物种多样性在中等环境梯度下最高。研究表明：土壤物理性质对秦岭松栎林建群树种形态及其群落多样性产生了显著影响,保持中等水平的容重及土壤持水量并适当提高灌木层丰富度和乔木层均匀度,有助于维持该群落较高的物种多样性水平。     

The biological importance of the Eastern Arc Mountains of Tanzania and Kenya

The Eastern Arc Mountains are renown in Africa for high concentrations of endemic species of animals and plants. Thirteen separate mountain blocks comprise the Eastern Arc, supporting around 3300 km² of sub-montane, montane and upper montane forest, less than 30% of the estimated original forested area. At least 96 vertebrate species are endemic, split as follows: 10 mammal, 19 bird, 29 reptile and 38 amphibian species. This includes four endemic or nearly endemic species of primate - the Sanje Mangabey, the Iringa Red Colobus, the Mountain Galago and the new Kipunji monkey that forms its own monotypic genus. A further 71 vertebrate species are near-endemic. At least 800 vascular plant species are endemic, almost 10% of these being trees. These endemics include the majority of the species of African violet - Saintpaulia, a well-known flowering plant in Western households. An additional 32 species of bryophytes are also endemic. Many hundreds of invertebrates are also likely to be endemic, with data for butterflies, millipedes and dragonflies indicating potential trends in importance. Seventy-one of the endemic or near-endemic vertebrates are threatened by extinction (8 critical, 27 endangered, 36 vulnerable), with an additional seven wide ranging threatened species. Hundreds of plant species are also threatened. Most Eastern Arc endemics are closed-forest specialists and comprise taxa with an ancient history and those of more recent origin, including some possessing ancient affinities with taxa from West Africa, Madagascar, and even South America and Southeast Asia. Mountain block prioritisation for biodiversity conservation shows that Udzungwas, East Usambaras and Ulugurus are the most important blocks, with other important blocks being the Ngurus and West Usambaras. Rankings are correlated closely with the area of remaining forest. Most of the remaining forest is found within nearly 150 Government Forest Reserves, with 106 of these managed nationally for water catchment, biodiversity and soil conservation and where forest exploitation is not allowed. Outside these areas most forest has been cleared, except in small village burial/sacred sites, a few Village Forest Reserves, and inaccessible areas. In most Eastern Arc Mountains the local populations have not encroached beyond the reserve boundaries to develop farms, but forest resources within the boundaries are used for fuel and building materials and some forests are heavily degraded. Fire is also a problem as it enters and destroys forests during the dry seasons. The future of the biodiversity on the Eastern Arc Mountains is closely tied to management policies and capacity of the Tanzania Forestry and Beekeeping Division, Tanzania National Parks Authority, and Kenya Forest Department. Supporting these agencies in their mandated job is an essential conservation investment over the longer term.     

秦岭地区藤本植物资源多样性研究

【目的】更好地开发利用野生藤本植物资源,丰富城市绿化美化的植物类群。【方法】采用样地与样线相结合的调查方法,对秦岭地区藤本植物的种类组成、地理分布区类型、攀援方式等进行了研究。【结果】(1)秦岭地区藤本植物种类丰富,共计36科98属285种,分别占本区种子植物科、属、种的18.18%,9.73%和8.27%,其中木质藤本164种,草质藤本121种;单子叶植物17种,双子叶植物268种。(2)秦岭地区藤本植物属有13个分布区类型,而热带性地理成分居首位,占53.84%。(3)秦岭地区藤本植物攀援方式有4大类,以缠绕类为最多,占50.53%;其次为卷须类和钩刺类,分别占31.23%和13.33%,吸附类藤本种类最少,只有4.91%。【结论】秦岭地区藤本植物资源丰富,开发利用潜力巨大,加强对野生藤本植物的引种驯化,可以丰富城市园林植物的多样性。