稻鸭共生有机栽培模式对黄河三角洲稻米品质的影响

在黄河三角洲地区设计稻鸭共生、人工除草、常规稻作3种栽培模式,研究其对稻米加工品质、外观品质、蒸煮和食味品质、卫生品质的影响.结果表明:与常规稻作相比,稻鸭共生可以增加水稻粒宽,提高糙米率、精米率、整精米率,减少垩白,这主要是由于有效穗数和籽粒重的提高以及弱势粒的降低所致.稻鸭共生和人工除草栽培模式可以增加胶稠度,降低直连淀粉和蛋白质含量,改善稻米食味性,这主要归功于有机肥的施用.由于生产过程不施用化学肥料和农药,稻鸭共生、人工除草模式可以大幅降低甚至检测不到农药残留.稻鸭共生既可改善稻米品质,又能保护环境,为优质水稻生产提供了一条较好的生态技术途径.     

环境因子和生物因子对黄河三角洲滨海湿地土壤呼吸的影响

采用Li-8150多通道土壤呼吸自动测量系统对黄河三角洲滨海湿地土壤呼吸进行全年连续测定,同步测量了温度、土壤含水量、地上生物量以及叶面积指数等环境因子和生物因子.结果表明: 土壤呼吸日动态在全年尺度上多呈单峰型,但在受到土壤封冻和地表积水干扰时,土壤呼吸日动态呈多峰型.土壤呼吸具有明显的季节动态特征,总体呈单峰型,年平均土壤呼吸速率为0.85 μmol CO₂·m^-2·s^-1,生长季平均土壤呼吸速率为1.22 μmol CO₂·m^-2·s^-1.在全年尺度上,土壤温度是滨海湿地土壤呼吸的主要控制因子,可解释全年土壤呼吸87.5%的变化.在生长季尺度上,土壤含水量和叶面积指数对土壤呼吸的协同影响达到85%.     

黄河三角洲植物群落分布格局及其影响因素

利用双向指示种分析和去趋势典范对应分析的方法,对典型河口滨海湿地黄河三角洲植物群落类型和结构进行了分析,并探讨了植物群落分布格局及其影响因素。结果表明：134个样方可划分为7个群系,即刺槐群落（Form. Robinia pseucdoacacia）、荻群落（Form. Miscanthus saccharifleus）、翅碱蓬群落（Form. Suaeda heteroptera）、獐毛群落（Form. Aeluropus sinensis）、芦苇群落（Form. Phragmites communis）、柽柳群落（Form. Tamarix chinensis）和白茅群落（Form. Imperata cylindrica）。群落类型的划分主要反映了微地貌所决定的地下水埋深及土壤盐分含量的变化。在影响植物群落分布格局的因素中,环境因子解释的部分占45.2%,空间因子解释的部分占11.8%,空间因子和环境因子交互作用解释的部分占2.23%,空间因子和环境因子未能解释的部分占40.8%,这部分主要反映了群落自身互作及人类活动对群落的影响。     

黄河三角洲草地退化的研究

黄河三角洲位于东经118°7′—119°10′,北纬36°56′—38°12′;东自山东省小清河口,西至徒骇河口,以利津县宁海为顶点向渤海湾呈扇形分布。自50年代以来,随着国营及地方农场的建立以及人口的不断增长,这一地区的草地资源得到了广泛的开发利用。但是,由于一些单位只顾盲目地开垦草地和过度放牧、割草,30多年来整个黄河三角洲盐碱化、退化草地达6.67×10~4ha多,约占当地草地总面积的40%。本文研究了该地区草地退化的现状并就退化程度与累计开发时间的关系初步进行了数     

基于遥感及突变理论的生态环境脆弱性时空演变——以黄河三角洲垦利县为例

本文应用熵、突变论等非线性科学理论研究生态环境脆弱性问题,借助遥感手段,设置生态环境样方,对黄河三角洲垦利县典型生态脆弱区的生态环境脆弱性的时空演变进行了系统研究,建立了生态环境脆弱性的分析与判断方法.结果表明：在1987—2005年间,样方生态环境趋于恶化,其生态环境脆弱性在1997年和2004年发生了两次突变,前者主要源于风暴潮和黄河来水量的减少,主要表现为生境的变化和优势种的更替;后者主要源于黄河来水量的减少和蒸降比的升高及水库的大量修建、道路和人口密度的增加,生态环境脆弱性主要表现为植被类型和覆盖率的变化.在空间层面,从与黄河和海洋不同距离的两个方向上,分析了生态环境脆弱性的空间变化,证明了生态环境脆弱性空间上的渐变性.该研究对生态环境脆弱性的定量化研究是一个新的尝试,并提供了一种新的有效方法.     

道路网络对景观生态风险的影响——以云南省红河流域为例

道路网络扩展既影响周围的景观格局,也对生态过程造成直接或间接的影响。以云南省红河流域为研究区域,利用GIS和RS技术,进行格网划分,从空间上分析道路对景观格局和土壤侵蚀的影响,并通过基于景观格局和过程的景观生态风险指数计算,分析道路网络扩展影响下的景观生态风险规律。结果表明:红河流域道路周围景观类型以耕地、林地和草地为主,其中林地和草地的格局风险指数随着距离道路的增加而减少,受道路影响显著;一级路、三级路和四级路缓冲区内土壤侵蚀量随着距离道路的增加而减少,三四级路分布广泛,更容易发生土壤侵蚀;道路密度和基于景观格局和过程的景观生态风险指数在空间分布上具有一定的相关性。     

黄河三角洲土壤动物多样性初步调查研究

1995～1996年对黄河三角洲9个代表性样区,进行了土壤动物定性、定量调查,并对古代、近代、现代黄河三角洲3个代表性样区开展了土壤动物周年调查,研究了土壤动物的种类组成、分布和季节变化,以及土壤动物多样性。调查研究结果：黄河三角洲共鉴定出土壤动物38种,土壤动物种类组成和数量分布因三个三角洲成土年龄不同而存在差异,土壤动物多样性以夏季为丰富。黄河三角洲土壤动物多样性与均匀度表现为正相关关系,与单纯度呈负相关趋势。     

黄河三角洲土壤运行多样性初步调查研究

1995－1996年对黄河三角洲9个代表性样区,进行了土壤运动定性,定量调查,并对古代,近代,现代黄河三角洲3个代表性样区开展了土壤动物周年调查,研究了土壤动物的种类组成,分布和节季变化,以及土壤动物多样性,调查研究结果,黄河三角洲共鉴定出土壤运动38种,土壤运动种类组成和数量分布因三个三角洲成土年龄不同而存在差异,土壤运动多样性以夏季为丰富,黄河三角洲土壤运动多样性]与均匀度表现为正相关关系,与单纯度呈负相关趋势。     

道路对景观的影响及其生态风险评价--以澜沧江流域为例

道路贯穿于各类景观。道路网络的发展也产生了许多生态效应。道路的生态风险分析是基于生态效应,通过格局和过程的研究,综合评估各类潜在生态影响及其累积性后果。从景观生态学理论入手．分析了道路对景观的影响,将道路对景观的影响区分为建设期和运营期2个阶段,并提出了基于格局和过程的生态环境指数,进而得出道路综合生态风险评价的方法。以澜沧江流域上中下游的3个典型区为例,研究道路对景观的影响。结果表明,虽然不同案例区道路影响的景观类型和格局不同,其风险的分布也不同．但综合风险指数和道路密度具有很高的一致性。     

黄河改道以来黄河三角洲演变过程及其驱动机制

基于1976—2009年的23期遥感影像,并结合1976—2008年利津站水沙数据以及黄河流域年均降水量数据,定量分析黄河入海水沙特征以及黄河三角洲演变过程及其驱动机制.结果表明:1976—2008年间,黄河入海年径流量和年输沙量呈现出年际变化大和丰枯水(沙)年交替的特征,但总体均呈下降趋势;清水沟流路河口三角洲岸线和面积变化总体呈淤积增长趋势,三角洲的发育过程大致分1976—1985年、1986—1995年和1996—2009年3个阶段,3个阶段的增长速率逐阶段递减;黄河三角洲岸线和面积与利津站累积输沙量之间均呈显著的指数函数关系;黄河流域降水量的年际波动与利津站入海输沙量年际波动基本同步,并具有相关性,说明黄河流域降水量的年际波动是引起入海径流量和输沙量波动的重要原因.     

Dioxin-like Polychlorinated Biphenyls Contamination and Distribution in Soils from the Modern Yellow River Delta,China

The concentrations of 12 dioxin-like Polychlorinated Biphenyls (dl-PCBs) were determined from 37 soil samples collected from the modern Yellow River Delta (China) in March 2006. The PCB concentrations were determined by dual capillary GC-ECD. The total dl-PCBs concentrations were in the range of 108.7 to 2153 ng/kg with an average of 800.5 ng/kg. The toxic equivalency (TEQ) in this area varies from 2.3 × 10^{? 5} to 9.5 × 10^{? 5} ng-TEQ/kg, so the delta is slightly polluted by PCBs. PCB118, the main congener, accounted for 46.7% of the total dl-PCB. More than 60% dl-PCBs were penta-PCBs. The spatial distribution of the dl-PCBs is discussed in detail. The distribution of the PCBs suggests that water runoff is the main source of the total contaminant burden in the delta, and that atmospheric precipitation plays an important role.     

Response of reed community to the environment gradient-water depth in the Yellow River Delta, China

We investigated and monitored a reed community in the fields. Data on the bio-ecological characteristics and β-diversity of reed communities in different environmental gradients (mainly based on water depth) of the Yellow River Delta were collected through multianalysis, extremum analysis and β-diversity index analysis. In accordance with the square sum of deviations (Ward) cluster analysis, 10 sampling plots were divided into six types with the dominant plants in different plots varying according to the change in environmental gradients. The dominant plants in these plots varied from aquatic plants to xerophytes and salt tolerant plants as water depth decreased. The average height and diameter of the reeds at breast level were significantly correlated with the average water depth. The fitness curves of average density and coverage with average water depth were nonlinear. When the average water depth was 0.3 m, the average density and coverage of reeds reached the apex value, while the height and diameter of the reeds at breast level increased with the water depth. There were obvious changes to the environmental gradient in the Yellow River Delta. The transitional communities were also found to exist in the Yellow River Delta by β-diversity analysis. Vicarious species appeared with the change in water depth. The occurrence of substitute species is determined by the function of common species between adjacent belts. The different functions of common species led to differences in community structure and function and differences in dominant plants. The result reflects the variations of species present in different habitats and directly reflects environmental heterogeneity. The values of β-diversity indices of adjacent plots were higher than those of nonadjacent plots. There are transition zones between the xerophytes and aquatic plants in the Yellow River Delta. In an aquatic environment, the similarity of reed community is higher than that of xeromorphic plants. The β-diversity index can reflect plant succession trends caused by the change in environmental gradients in the Yellow River Delta. The β-diversity index reveals plant responses to changes in environmental gradient and is helpful in observing changes in patterns of species diversity in relation to environmental gradient change and evolving trends in the future, which in turn plays a prominent role when environmental water requirements of wetland are discussed. __________ Translated from Acta Ecologica Sinica, 2006, 26(5): 1533–1541 [译自: 生态学报]     

Heavy metals in wetland soils along a wetland-forming chronosequence in the Yellow River Delta of China: Levels,sources and toxic risks

Surface soil (0–20 cm) samples were collected from four chronological sequences of wetlands (i.e., >50-yr-old wetlands, 40-yr-old wetlands, 30-yr-old wetlands and 10-yr-old wetlands) in the Yellow River Delta of China in May and June of 2007. Total contents of Al, As, Cd, Cr, Cu, Ni, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry (ICP-AAS) to investigate the levels, sources and toxic risks of heavy metals in these wetlands. Our results showed an increasing trend for Pb, Cu and Zn along the wetland-forming chronosequence although their pollution levels were low. Both As and Cd exhibited significant enrichment due to their high enrichment factor (EF) values (EF > 5), especially in older wetlands (i.e., >50-yr-old and 40-yr-old wetlands), whereas other heavy metals were minimally or moderately enriched in this region. The results of principal component analysis showed that 83.09% of total variance based on eigenvalues (eigenvalue > 1) could be explained by three principal components (PCs) in four wetlands. The source of Al, Cu, Pb and Zn was different from Cd, Cr and Ni. According to the sediment quality guidelines (SQGs) of China, soil samples in the younger wetlands, especially the 10-yr-old wetlands, were moderately polluted by As, Cd and Ni. According to the SQGs of US EPA, all soil samples were heavily polluted by As and moderately polluted by Ni and soil samples in the older wetlands were moderately polluted by Cr. However, with the exception of As and Ni, the contents of other heavy metals in the four wetlands did not exceed the probable effect level (PEL) values. As, Cd and Ni were identified as heavy metals of primary concerns in four wetlands, Cr were of moderate concern in older wetlands, and Pb, Cu and Zn should be paid more attention in younger wetland (i.e., 10-yr-old and 30-yr-old wetlands). A new and sensitive toxic risk index (TRI) is developed for the accurate assessment of toxic risk for heavy metals in wetland soils compared with the sum of the toxic units (∑TUs), and As, Cr, Ni and Cd showed higher contributions to TRI.     

黄河三角洲湿地草本植被的双变量主坐标排序

利用双向指示种（TWINSPAN）分类技术将黄河三角洲湿地草本植被划分为7个群落类型,然后应用双变量主坐标分析（double principal coordinate analysis, DPCoA）法对其进行排序,结果表明：在物种组成上,芦苇＋盐地碱蓬群落为芦苇群落和盐地碱蓬＋芦苇群落、盐地碱蓬群落、盐地碱蓬＋补血草＋碱蓬群落、补血草群落的过渡类型,而芦苇＋穗状狐尾藻群落与其他群落类型差异较大;黄河三角洲湿地草本植被的分布主要与土壤因子中的土壤盐分、土壤pH等紧密相关,而与土壤全磷、全氮、有机质等养分无显著相关关系。将DPCoA和其他一些常用的植被排序方法进行了比较,相对于主分量分析（PCA）和除趋势对应分析（DCA）而言,DPCoA信息保留量更高,能够将物种组成和类别上较为接近的植物群落聚集在一起,而将差异较大的植物群落在排序图中分散开来,在揭示群落间相互关系以及植被与环境之间关系上可能更为有效。     

黄河三角洲湿地生态系统的形成及其保护

通过对黄河三角洲新生湿地的野外调查,利用TM陆地卫星影像图的判读,结合黄河尾闾变动的历史资料分析,结果表明,黄河三角洲新生湿地是多泥沙的黄河淤积和海岸蚀退所形成.受区域气候、地貌、地质沉积、土壤、植被的相互作用和互相影响,形成4.5×10⁵hm²的湿地,其中有6.84×10⁴hm²的人工湿地.湿地生态类型随着黄河尾闾摆动和海退陆进程度而变化,自海洋向陆地依次为潮下带水生生态系统潮间带湿地生态系统潮上带盐生生态系统芦苇獐茅湿地生态系统草甸湿地生态系统陆上农田生态系统.该系统资源丰富,共有野生动物1524种,鸟类300种,鱼类1040种.石油开发和近年来黄河断流对湿地产生一定影响,应在开发利用中加强管理和保护.     

黄河三角洲湿地生态系统的形成及其保护

通过对黄河三角洲新生湿地的野外调查,利用TM陆地卫星影像图的判读,结合黄河尾闾变动的历史资料分析,结果表明,黄河三角洲新生湿地是多泥沙的黄河淤积和海岸蚀退所形成.受区域气候、地貌、地质沉积、土壤、植被的相互作用和互相影响,形成4.5×105hm2的湿地,其中有6.84×104hm2的人工湿地.湿地生态类型随着黄河尾闾摆动和海退陆进程度而变化,自海洋向陆地依次为潮下带水生生态系统潮间带湿地生态系统潮上带盐生生态系统芦苇獐茅湿地生态系统草甸湿地生态系统陆上农田生态系统.该系统资源丰富,共有野生动物1524种,鸟类300种,鱼类1040种.石油开发和近年来黄河断流对湿地产生一定影响,应在开发利用中加强管理和保护     

Patterns of alien plant diversity in the urban landscapes of global biodiversity hotspots: a case study from the Himalayas

In an age of Anthropocene, the urban landscapes are recognised as the ‘hotspots’ of human-mediated alien species introductions. As the cities provide an ideal natural experimental system to investigate the patterns of alien plant diversity in urban landscapes, the present study aimed to unravel the taxonomic, biogeographic and ecological patterns of alien flora of Srinagar—one of the largest urban centres in the Himalayan biodiversity hotspot. The alien flora of Srinagar comprises 325 species, constituting ca.35% of total flora of the city. Out of the 325 alien species documented, 157 species (43%) were recorded to be under cultivation, while 168 species (57%) were growing in the wild (i.e., outside cultivation); those growing in the wild, in turn, comprised 110 cultivation escapes and 58 accidentally introduced plant species. Biogeographically, two-third of the alien plant diversity reported from Srinagar is native to Asia-Temperate. This indicates that climatic similarity between Asia-Temperate and Kashmir Himalayas facilitate in flourishing similar floristic diversity. The study highlights a relatively higher proportion of herbaceous growth form in the aliens growing in the wild (80%) than those under cultivation (43%). Similarly, 82% of the alien species under cultivation had a perennial life span, but those growing in the wild were dominated by annuals (44%). Currently, 45 species are growing as casuals and 124 species are naturalised (including 105 naturalised non-invasive and 19 naturalised invasive). Along the continuum of casual-naturalised-invasive categories, the contribution of cultivation escapes and accidently introduced aliens contrastingly shows decreasing and increasing trends respectively. Interestingly, the results revealed that the human practice of stopping cultivation of alien escapes increased rapidly as we move along the continuum. Thus, the present study has investigated the patterns of alien plant diversity in the urban landscape of Srinagar, and the results obtained offer scientific insights toward better scientific understanding and management of plant invasions in this Himalayan city, with wider policy implications for neighbouring urbanised landscapes in the Himalayas and other mountainous regions across the world.     

Estimating biodiversity: a case study on true bugs in argentinian wetlands

The species richness and relative abundance of faunas in defined areas are the raw materials in biodiversity science. The research methodology to acquire these data is inventory, and inventory quality depends on a number of parameters, for example collecting methods, season, and collector experience. To assess the ability of rapid inventory techniques to estimate local richness seven collectors sampled the fauna of true bugs in the Iberá watershed (Corrientes, Argentina) with seven methods during early spring, summer, and late summer (December, May, September) of 1 year. Twenty-three families, 225 spp. and 4,678 adults were found. We also applied various statistical techniques to correct the observed data for undersampling bias, which suggested the lower bound of annual heteropteran species richness at Pellegrini was about 250–300 species. Among heteropteran families, the particular inventory methodology was especially efficient in sampling Miridae. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.