首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
烟台潮间带底栖无脊椎动物群落和多样性研究   总被引:9,自引:1,他引:8  
丛建国 《生态学报》1998,18(1):56-62
每年1次连续7a夏季对烟台海滨沓间带的沙滩、泥沙滩、泥沙砾石滩及海港码头(岩石、泥沙底质)5种生境的无脊椎动物群落进行定时、定点取样调查。经鉴定共有无脊椎动物128种。经Berger-Parker优势度指数测定,主要优势种为东方小藤壶Chthamalus challengeri、短滨螺Littoriina brevicula、异白樱蛤Macoma incongrus、托氏昌螺Umbonium th  相似文献   

2.
内蒙古锡林河流域羊草草原生态系统碳素循环研究   总被引:23,自引:0,他引:23  
采用野外调查和模型预测方法相结合,对内蒙古锡林河流域一个永久试验样地内的羊草(Leymuschinensis(Trin.)Tzvel.)草原群落的碳素贮量、主要流量和周转速度等进行了初步估计,研究了长期过度放牧对整个流域羊草草原土壤有机碳贮量的影响。结果表明:1)羊草群落净初级生产固碳量的多年实测平均值为(231.25±74.41)gC·m-2·a-1,向土壤中的碳素输入量为220.75gC·m-2·a-1,土壤呼吸量的模型预测值为(181.03±46.32)gC·m-2·a-1;2)该群落碳素输入略大于输出,其理论积累率为19.88gC·m-2·a-1,实测积累率为39.72gC·m-2·a-1;3)近40年来,过度放牧致使锡林河流域羊草草原表层(0~20cm)土壤的有机碳贮量下降了约12.4%。  相似文献   

3.
哀牢山木果石栎群落优势种的生态位宽度与重叠   总被引:24,自引:0,他引:24  
通过多种方法比较研究了哀牢山木果石栎(Lithocarpus xylocarpus)群落8个优势种的生态位宽度和重叠,结果表明,该群落是以木果石栎、腾冲栲(Castanopsis wattii)、滇木荷(Schima noronhae)和景东石栎(Lithocarpus chintungensis)为优势种的共优群落,它们的生态位宽度值分别为0.8732,0.7856,0.6742和0.5798。  相似文献   

4.
湖南新邵巨口铺中泥盆世棋梓桥期台缘礁可分为5个群落(自下而上):Stromatopora-Clathrocoilona群落;(2)Argutastrea-Stromatopora群落;(3)Crinoids-Clathrocoilona群落;(4)Clathrocoilona-Planocoenites群落;(5)Amphipora-Actinostroma群落。对每个群落的居群数(S),相对丰度(P),分异度(H),优势度(C)和均衡度(E)以及生物生活方式、进食类型等进行了计算和描述。根据各居群在礁体形成过程中所起的作用,划分为5个群团:建造者、粘结者、保护者、居住者和破坏者。礁体发育经历4个阶段,每个阶段都有一定的造礁方式──格架式、捆结式、盖覆式和障积式。文中共鉴定80种、54属,分属于11个大类。  相似文献   

5.
紫金山含明党参早春草本层的群落学分析   总被引:7,自引:0,他引:7  
在1 ̄7月对紫金山紫薇-山胡椒群落(Form.Lagerstroemis indica-Lindera glauca)的早春草本层进行了定位连续的群落学调查统计。结果表明,生于落叶林下的含明党参(Changium smyrnioides smyrnioids Wolff.)早春草本层植物通常2月萌芽,在早春落叶乔木尚未展叶林内透光好的条件下旺盛生长,在6月初落叶乔木展叶郁闭度增高后完成生活史。早春  相似文献   

6.
冯伟民  蓝 《古生物学报》2000,39(2):285-294
中沙、西沙群岛海底21个表层沉积样中发现微型腹足类176种,微型双壳类48种,形成3组合类型:水深0-60m为Tricolia(Hiloa)variabilis-Cadella semitorta组合,水深60-120m为Cerithiopsis-Ringicula-Varicorbula组合,水深大于800m为Anatomia-Gastrochaena组合。腹足类、双壳类沉积组合包括原地理藏和异  相似文献   

7.
1995—1999年黄河三角洲东部自然保护区湿地景观格局变化   总被引:1,自引:0,他引:1  
刘艳芬  张杰  马毅  单凯  靳晓华  王进河 《生态学杂志》2010,21(11):2904-2911
基于1995和1999年的Landsat TM遥感影像,结合地理信息系统技术,分析黄河改道清8汊(1996年)前后的1995—1999年黄河三角洲东部自然保护区(位于黄河现行流路入海口处)湿地景观格局的变化特征,以及影响湿地景观格局变化的驱动因素.结果表明:1995—1999年,保护区湿地仍以天然湿地为主,人工湿地比重极小,期间非湿地面积大幅增加,而天然湿地和人工湿地面积则呈下降趋势,其中,裸露淤泥质滩涂和沼泽湿地面积明显萎缩;尽管保护区湿地景观类型、形状、结构的变化程度不均一,且各景观类型在空间分布上的团聚程度变化不均衡,但总的看来,保护区景观整体结构趋于复杂化,破碎化程度有所加深,内部各景观类型从大块连续的镶嵌分布向小块离散分布转变;影响保护区湿地景观格局变化的主要因素有3个:黄河改道、黄河断流和人类活动.  相似文献   

8.
1995—1999年黄河三角洲东部自然保护区湿地景观格局变化   总被引:3,自引:1,他引:2  
基于1995和1999年的LandsatTM遥感影像,结合地理信息系统技术,分析黄河改道清8汊(1996年)前后的1995—1999年黄河三角洲东部自然保护区(位于黄河现行流路入海口处)湿地景观格局的变化特征,以及影响湿地景观格局变化的驱动因素.结果表明:1995—1999年,保护区湿地仍以天然湿地为主,人工湿地比重极小,期间非湿地面积大幅增加,而天然湿地和人工湿地面积则呈下降趋势,其中,裸露淤泥质滩涂和沼泽湿地面积明显萎缩;尽管保护区湿地景观类型、形状、结构的变化程度不均一,且各景观类型在空间分布上的团聚程度变化不均衡,但总的看来,保护区景观整体结构趋于复杂化,破碎化程度有所加深,内部各景观类型从大块连续的镶嵌分布向小块离散分布转变;影响保护区湿地景观格局变化的主要因素有3个:黄河改道、黄河断流和人类活动.  相似文献   

9.
浙江天台山甜槠群落物种多样性   总被引:6,自引:0,他引:6  
金则新 《生态学杂志》2002,21(3):1-4,14
甜槠 (Castanopsiseyrei)林为中亚热带典型的地带性植被 ,是浙江省最常见的常绿阔叶林类型。在浙江省天台山石梁景区内分布着一片以甜槠为单优势的群落 ,作者曾对该群落的特征作了初步的研究[6] 。本文主要对甜槠群落的区系组成、物种多样性、种多度分布、科 属 种组成多样性等进行了测定和分析 ,为甜槠群落的多样性保护与持续利用提供科学依据。1 研究地自然概况与研究方法1.1 自然概况天台山位于浙江省东部 ,有关其自然概况已作多次报道[6] ,这里不再重复。1.2 样地的设置在甜槠群落中 ,根据不同海拔高度和坡向设置1…  相似文献   

10.
记述了湘西北地区志留、泥盆系的遗迹化石14属,28种、亚种(包括15新种,2新亚种)。这些遗迹化石主要集中于Traueumichis-Arthrophycus群落(代表前滨下部或近滨上部),Thalassinoides-Lockeia群落(代表近滨上部或前滨下部环境)和Cruziana-Dimorphichnus群落(代表近滨环境),并对上述3个遗迹群落的古生态作了分析。  相似文献   

11.
12.
13.
14.
15.
Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.  相似文献   

16.
Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.  相似文献   

17.
Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.  相似文献   

18.
正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases  相似文献   

19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号