微生境尺度上放牧退化草原群落特征与土壤有机质的空间分异性   总被引：1，自引：1，他引：0  

乌云娜  雒文涛  霍光伟  吕建洲  李海山  胡高娃 《中国沙漠》2012,32(4):972-979

 格局和过程与异质性有关。以呼伦贝尔克氏针茅草原不同放牧强度下的演替群落为对象,开展群落植被空间分布格局及土壤有机质空间异质性研究。结果显示,不同放牧强度样地群落结构和群落种类组成存在明显差异。轻度放牧样地样方内有8种植物,群落优势种为克氏针茅（Stipa krylovii）;中度放牧样地样方内有12种植物,群落优势种为糙隐子草（Cleistogenes squyarrosa）;而重度放牧样地样方内只有7种植物,群落优势种为多根葱（Allium polyrhizum）。随放牧强度的增强,植被地上生物量及其变异系数逐渐降低;土壤有机质含量表现为轻度放牧>中度放牧>重度放牧,而其变异系数表现为中度放牧>轻度放牧>重度放牧。从植被地上生物量和土壤有机质含量变异函数分析来看,随放牧压力的增大,植被地上生物量空间自相关性增强,空间异质性变大;土壤有机质含量空间分布自相关性先增强,然后减弱,空间变异性先变大,然后变小。在10 cm×10 cm的微尺度上,重牧群落植被地上生物量和土壤有机质含量之间表现出明显的相关性（P<0.05）。  相似文献   

Polarimetric scattering model for estimation of above ground biomass of multilayer vegetation using ALOS-PALSAR quad-pol data     

《Physics and Chemistry of the Earth》2015

Forests are important biomes covering a major part of the vegetation on the Earth, and as such account for seventy percent of the carbon present in living beings. The value of a forest’s above ground biomass (AGB) is considered as an important parameter for the estimation of global carbon content. In the present study, the quad-pol ALOS-PALSAR data was used for the estimation of AGB for the Dudhwa National Park, India. For this purpose, polarimetric decomposition components and an Extended Water Cloud Model (EWCM) were used. The PolSAR data orientation angle shifts were compensated for before the polarimetric decomposition. The scattering components obtained from the polarimetric decomposition were used in the Water Cloud Model (WCM). The WCM was extended for higher order interactions like double bounce scattering. The parameters of the EWCM were retrieved using the field measurements and the decomposition components. Finally, the relationship between the estimated AGB and measured AGB was assessed. The coefficient of determination (R²) and root mean square error (RMSE) were 0.4341 and 119 t/ha respectively.  相似文献   

Biotechnology of Metal Removal from Industrial Wastewater: Zinc Case Study          下载免费PDF全文

Inga Zinicovscaia  Gheorghe Duca  Liliana Cepoi  Tatiana Chiriac  Ludmila Rudi  Tatiana Mitina  Marina V. Frontasyeva  Sergey Pavlov  Svetlana F. Gundorina 《洁净——土壤、空气、水》2015,43(1):112-117

  相似文献   

Size scaling patterns of species richness and carbon biomass for marine phytoplankton functional groups          下载免费PDF全文

Lydia Ignatiades 《Marine Ecology》2017,38(5)

Phytoplankton assemblages were clustered into associations according to functional taxonomic (diatoms, dinoflagellates and coccolithophores) and “ataxonomic” unimodal (nanoplankton, microplankton and macroplankton) size‐based criteria. Scaling relations of species richness‐cell size were performed in terms of histogram and log‐transformed data analyses for both taxonomic and ataxonomic groups. Frequency distribution histograms were fitted to a negative power function, which was strongly unimodal and right skewed and invariant across taxonomic and ataxonomic units. Regression analyses of the log‐transformed data were fitted to negative linear curves, which had common patterns and they were independent of taxonomic or ataxonomic affiliation. Species carbon biomass–cell size spectra produced by log transformation of the relevant data yielded positive slopes for both taxonomic and ataxonomic groups. In contrast, comparisons of the relative cell abundance, cell volume and carbon biomass levels showed large differences among these variables across taxonomic and ataxonomic groups. This work demonstrates that phytoplankton taxonomic and ataxonomic functional group relationships should be considered when developing future models of phytoplankton community structure.  相似文献   

山东半岛近岸海域蟹类群落结构特征的研究     

杨刚  李凡  吕振波  徐炳庆  袁小楠  王秀霞  陈伟杰 《海洋学报》2017,39(8):48-61

根据2014年8月和10月、2015年2月和5月使用单船底拖网进行的4个航次调查数据,对山东半岛近岸海区的莱州湾及渤海南部、山东半岛北部和山东半岛南部等3个海域蟹类种类组成、时空分布、优势种、群落结构稳定性等群落结构特征进行了研究。结果显示,4次调查共捕获蟹类20种,隶属于10科17属,其中日本蟳（Charybdis japonica）和三疣梭子蟹（Portunus trituberculatus）是主要经济种类,其余均为小型饵料型蟹类;海区内主要的优势种为双斑蟳（Charybdis bimaculata）、日本蟳（Charybdis japonica）和三疣梭子蟹（Portunus trituberculatus）,3个海域优势种季节更替均十分明显;莱州湾及渤海南部和山东半岛南部2个海域生物量季节变化明显,春季较低,在夏季达到峰值,夏季到冬季呈降低趋势,山东半岛北部海域生物量季节变化不明显。3个海域蟹类群落物种多样性指数（H'）、丰富度指数（D）及均匀度指数（J'）均处于较低水平,并有一定的季节变化;水深、水温和盐度是影响蟹类群落结构的重要因子,渤莱沿岸流、黄海暖流和黄海冷水团通过影响海域内水温与盐度影响蟹类群落结构。研究表明山东半岛近岸海区蟹类以小型饵料型蟹类为主,蟹类多样性水平较低,优势种更替明显,群落季节更替指数较高,季节间迁移频繁,蟹类群落不稳定。  相似文献   

辽河口邻近海域小型底栖生物的空间分布及季节变化   总被引：2，自引：1，他引：1  

叶晟  孔飞  李宏俊  刘敏  李洪波  邵魁双  樊景凤  郭皓 《海洋学报》2017,39(10):78-89

本文研究了辽河口邻近海域2013年8月、10月和2014年5月3个航次小型底栖生物的种类及其空间分布,分析了小型底栖生物丰度和生物量的季节变化。结果表明,3个航次（夏季、秋季和春季）小型底栖生物的平均丰度分别为（264±83） ind/（10 cm2）、（216±85） ind/（10 cm2）和（227±67） ind/（10 cm2）,平均生物量分别为（272±125）μg/（10 cm2）、（207±89）μg/（10 cm2）和（244±103）μg/（10 cm2）。与其他研究海域相比,辽河口小型底栖的丰度和生物量处于较低水平。共鉴定出了14个小型生物类群,按照丰度排序,线虫是最优势的类群,夏季、秋季和春季3个航次占总丰度的比例分别为94.0%、92.5%和90.8%;其他优势类群为多毛类、桡足类和双壳类。小型底栖生物量的优势类群则为多毛类（41.1%~44.0%）,高于线虫（33.8%~36.5%）,其次是双壳类（2.6%~6.7%）。水平分布的研究表明,调查海域近岸入海口小型底栖生物的丰度和生物量普遍低于近海海域,但是秋季时近岸分布与近海差距不大。垂直分布的研究表明,95.9%的小型底栖生物分布于0~5 cm的表层沉积物中。小型底栖生物的丰度和生物量在夏季时都达到高峰值。与环境因子的相关分析表明,小型底栖生物的数量分布与盐度和水深呈极显著正相关（P<0.01）,与叶绿素a呈显著正相关（P<0.05）。  相似文献   

Contrasting hydrography and phytoplankton distribution in the upper layers of cyclonic eddies in the Mozambique Basin and Mozambique Channel     

T Lamont  RG Barlow 《African Journal of Marine Science》2017,39(3):293-306

Hydrographic data collected in cyclonic eddies in the Mozambique Channel and Basin revealed notable differences in temperature and salinity at a depth of 100 m, the upper mixed layer, the nitracline depths, and vertical distribution of chlorophyll-a (Chl-a). Differences in temperature and salinity did not show any consistent patterns. In contrast, the differences in the upper mixed layer, nitracline depths and the vertical Chl-a profile appeared to be driven by combined effects of eddy dynamics (i.e. shoaling of isopleths) and the seasonal variation in light availability and mixing conditions in the upper layers. Cyclonic eddies studied during austral spring and summer in the Mozambique Channel exhibited shallower upper mixed layers and nitracline depths, and deeper euphotic zones. Distinct subsurface Chl-a maxima (SCM) were associated with the stratified conditions in the upper layers of these eddies. In contrast, a cyclonic eddy studied during mid-austral winter in the Mozambique Basin had a shallower euphotic zone, deeper upper mixed layer and uniform Chl-a profiles. Another eddy sampled in the Mozambique Basin toward the end of winter showed a less pronounced SCM and roughly equal euphotic zone and upper mixed layer depths, suggestive of a transition from a well-mixed upper layer during winter to stratified conditions in summer.  相似文献   

祁连山干旱山地草地生物量对水分条件的响应     

王顺利  王荣新  敬文茂  赵维俊  牛赟  马剑  朱红 《干旱区地理》2017,40(4):772-779

以祁连山排露沟流域干旱山地为研究对象,对海拔2 700~3 000 m典型草地群落的草本种类、高度和生物量等进行调查,并同步测定样地内的土壤水分,分析草地生物量随海拔高度的季节性变化特征以及草本生物量和土壤水分的关系。结果表明：（1）草地地上生物量平均值为135.36 g·m^-2,并随海拔升高呈先增加后降低的"单峰"变化模式,在海拔2 900 m时最高,为176.79±28.37 g·m^-2。地下生物量平均值为946.13 g·m^-2,并随海拔升高生物量呈递增趋势,在海拔3 000 m时最高,为1 301.19 ±68.24 g·m^-2。（2）草地地上、地下生物量在不同海拔高度间差异性显著（P<0.05）;该流域干旱山地草地根冠比在4.14~11.95之间变化。（3）在生长季5~9月份,干旱山地草地土壤含水量在9.23%~31.31%之间波动,平均值为14.94%。（4）草本地上、地下生物量与土壤平均含水量均呈显著正相关（P<0.05）,相关性系数分别为0.7784和0.7843。在不同海拔草地群落中,不同土层含水量对草地生物量的贡献不尽相同,但60 cm以上根系主要分布层内的水分对草地生物量具有重要的意义。  相似文献   

Organic carbon and microbial biomass in a raised beach deposit under terrestrial vegetation in the High Arctic, Ny-Ålesund, Svalbard     

Takayuki Nakatsubo  Shinpei Yoshitake  Masaki Uchida  Masao Uchida  Yasuyuki Shibata  & Hiroshi Koizumi 《Polar research》2008,27(1):23-27

  相似文献   

腾格里沙漠东南缘4种灌木的生物量预测模型     

杨昊天  李新荣  王增如  贾荣亮  刘立超  高艳红  李刚 《中国沙漠》2013,33(6):1699-1704

灌木生物量模型是预测灌木生物量最有效的方法。选择腾格里沙漠南缘荒漠生态系统中常见的4种灌木（驼绒藜(Ceratoides latens)、盐爪爪(Kalidium foliatum)、珍珠猪毛菜(Salsola passerina)、红砂(Reaumuria soongarica)）为研究对象,以株高（H）和冠幅（C）的复合因子灌木体积（V）为自变量,通过回归分析,分别构建了4种灌木和混合物种的叶、新生枝、老龄枝、地上部分、地下部分和整株生物量的预测模型。通过决定系数（R2）、估计值的标准误（SEE）和回归检验显著水平（p＜0.05）筛选出了最优的生物量估测模型。结果显示:4种灌木的生物量模型主要以幂函数W=aVb为最优模型,少数以三次函数W=a+bV+cV2+dV3为最优模型。灌木生物量与V之间呈极显著的相关关系（p＜0.001）,决定系数较高,分别为:叶片（0.775＜R2＜0.866）,新生枝（0.694＜R2＜0.840）,老龄枝（0.819＜R2＜0.916）,地上部（0.832＜R2＜0.917）,地下部分（0.74＜R2＜0.808）,全株（0.811＜R2＜0.912）,说明预测模型可以应用于此4种灌木的生物量估算。不同物种之间及不同器官之间的生物量模型存在差异,在实际使用中,要根据物种来选择相应的模型。生物量模型的建立有助于全面估算荒漠生态系统的生物量,并进一步评估生态系统不同碳库的碳存储量与碳循环。为有效提高荒漠草地碳储量、合理实施生态系统管理和人为干预提供科学依据。  相似文献