艾比湖湿地自然保护区植物群落数量分类研究

为了研究新疆艾比湖湿地自然保护区内植物群落的分类和排序,给湖区湿地生态恢复和植物多样性保护提供具有实践价值的参考依据,应用双岐指示种分类法(TWINSPAN)和DCA排序方法分析了新疆艾比湖湿地自然保护区25种主要植物在47个调查样地内的存在-缺失数据。结果表明：TWINSPAN将艾比湖湿地25种主要植物种划分为8个群丛,各群丛内的植物种之间具有相似的生境;DCA排序第1轴反映了土壤含水量梯度,第2轴反映了海拔梯度;TWINSPAN和DCA 2种方法对样地和植物种的分类、排序结果一致,能够有效处理艾比湖湿地植物种分布的稀疏性。     

Environmental characteristics and distribution of macrobenthos in a mudflat of the west coast of Korea (Yellow Sea)

The spatio-temporal changes of environmental factors and the distribution patterns of macrobenthos were investigated on an intertidal mudflat near Panweol on the west coast of Korea. Temperatures of the surface sediments and salinities of the intertitial water were highest in summer and lowest in winter, while water content of the sediment was lowest in summer and highest in winter. Hourly variations of sediment temperature, water content and interstitial salinity during the daytime depended largely upon both the timing of ebb tide and daylight intensity.Temperature, water content and interstitial salinity showed a marked variation with sediment depth. Temperatures decreased sharply from the surface to 10 or 15 cm depth, and below this depth they were nearly constant, except in summer. Water content and interstitial salinity underwent a rapid decline in this upper layer and began to rise from this depth. From the high tide mark toward the main tidal channel, water content increased but salinity decreased. The sand fraction increased with the decrease of clay content toward the main tidal channel. This tidal flat could be divided into two zones: the “upper intertidal zone” and the “lower intertidal zone”, based on the spatial differences of the water content, interstitial salinity and grain-size composition in the surface sediment.There were three distinct zones of macrobenthos. The upper intertidal zone was dominated by burrowing deposit feeders, such as Ilyoplax dentimerosa, Helice tridens sheni, Cleistostoma dilatatum and Perinereis vancaurica tetradentata. The middle intertidal zone was characterized by other burrowing deposit feeders, such as Ilyoplax pingi, Macrophthalmus japonicus and Periserrula leucophryna. And the lower intertidal zone was dominated by suspension feeders represented by Laonome tridentata and Potamocorbula amurensis. Each zone was named after these characteristic species.Although the species composition of the upper intertidal community was different from that of the middle intertidal, the way of living and the feeding behaviour of the species occurring in these two zones were very similar. But the lower intertidal zone showed a characteristic community structure differing not only in species composition but also in ways of living and feeding of the species. Some sets of environmental factors are considered to explain the zonation. Water content of the sediment and interstitial salinity will be the main factors causing the observed zonation.     

安太堡露天煤矿区复垦地不同植被下草本植物群落生态关系研究

为揭示不同植被下草本植物群落与环境因子的关系,本研究采用双向指示种分析(TWlNSPAN)、除趋势对应分析(DCA)、丰富度指数(Pa)、多样性指数(H'、DS)和均匀度指数(JP)方法,对安太堡露天煤矿区排土场复垦地不同植被下草本植物群落进行了数量分类、排序及物种多样性研究。结果显示：（1）TWlNSPAN等级分类将其63 个样方划分为11 个草本植物群丛,分别位于该矿区复垦地不同植被类型下;（2）DCA第一轴反映了植被恢复年限的梯度变化,沿第一轴从左到右,11 个草本植物群丛的恢复年限逐渐缩短;DCA第二轴反映了排土场复垦地地形的梯度变化,沿第二轴从下到上,地形从平台→东北坡,11 个草本植物群丛的物种多样性降低;（3）随着植被恢复年限的增长,11 个草本植物群丛物种多样性从高到低的变化为：平台＞东北坡,乔木林下＞灌丛林下＞草地。研究表明,植被恢复年限、植物种类和地形是影响安太堡露天煤矿区复垦地不同植被下11个草本植物群丛结构和物种多样性的关键因子。     

The role of epibenthic predators in structuring the marine invertebrate community of a British coastal salt marsh

The marine fauna of salt marshes are subjected to predation by birds, tidally feeding flatfish, crabs, prawns and small gobiid fish. The role of these epibenthic predators in structuring the community was investigated using cages to exclude predators. A range of designs of cages and partial cages was employed to control for artefacts due to caging, and sufficient cages were employed so that each cage was only sampled once to prevent the compounding of disturbance due to predation and sampling. Two mesh sizes were employed, a fine mesh excluding epibenthic predators and a coarse mesh allowing access by small crabs, prawns and gobiid fish but excluding birds and larger fish. The exclusion was maintained for 2 years. The presence of any experimental structure had a significant effect on the sedimentary regime within the cage. Epibentic predator exclusion let to an increase in infaunal predator density, but had no significant effect on the infaunal deposit feeders. There was some evidence that predators limit the surface deposit feeding gastropood Hydrobia ulvae during the winter. The gastropod Littorina littorea responded positively to the presence of any caging structure; this may be the result of changes in the availability of food, as the sides of a cage support a diatom flora which this species can exploit. The lack of a response from the infaunal deposit feeders is attributed to their horizontal mobility within the sediment. The possible interactions between epibenthic and infaunal predators are discussed.     

长江镇江和畅洲水域鱼类群落组成及环境影响因子

为了解长江镇江段和畅洲鱼类群落组成现状及其与水环境因子的相关性,本研究于2016年11月—2017年10月在长江镇江和畅洲水域进行周年调查,运用冗余分析法(RDA)分析鱼类群落组成与环境因子的相关关系。结果显示,共采集鉴定鱼类79种,隶属于9目17科57属,其中鲤形目鱼类占据绝对优势。部分水环境因子如正磷酸盐、水温、水深对鱼类群落组成具有显著影响(P<0.05),草鱼、鲫与正磷酸盐浓度相关性最大,鳡、贝氏䱗与水深的相关性最大,蒙古鲌、青鱼与水温的相关性最大。潮汐也是影响鱼类群落组成的关键因子,总体上表现为大潮期的渔获物种数和渔获尾数较多,但差异不显著。研究结果补充了长江下游段鱼类的基础数据,对该流域渔业资源评估与保护提供了科学依据。     

山西中条山十八河铜尾矿库自然定居草本植物群落与环境的关系

为揭示铜尾矿库自然定居草本植物群落与环境的关系,本文在中条山矿区十八河铜尾矿库进行植物样方的基础上,采用TWINSPAN分类、DCA和CCA排序相结合的方法,对该尾矿库自然定居草本植物群落进行数量分类与排序研究。结果表明：1)TWINSPAN分类方法将51个自然定居草本植物样方划分为两大类10个群丛,一类主要是以湿生草本植物芦苇(Phragmites communis)为主的群丛,另一类主要是以中生草本植物垂柳(Salix babylonica)幼苗为主的群丛；2)DCA排序第一轴反映了草本植物群落分布与土壤水分的关系,沿第一轴从左到右,土壤水分含量逐渐降低,草本植物种类由湿生植物向中生、旱中生植物逐渐过渡；DCA排序第二轴反映了植被生活型的变化,沿第二轴由下到上,自然定居草本植物种类由一年生向多年生演替；3) CCA排序第一轴与土壤湿度和土壤电导率有关,反映了是群落由湿生植物→中生植物和耐盐性植物；第二轴与物种丰富度等指数有关。     

北太平洋海温异常对四川省春季林火的影响

为保护和发展四川省生态环境和森林资源,完善四川省森林火险预报预警业务,笔者利用四川省1979—2012年森林火灾观测数据、NCEP/NCAR再分析环流资料以及美国NOAA全球海表温度资料,分析了四川省森林火灾的时空分布特征,并对前期海温影响林火的可能机制进行了探讨。结果显示：四川省林火重灾区（凉山州、攀枝花市和甘孜州）春季林火次数与冬季北赤道暖流区(5°—25°N, 165°E—140°W)海温呈显著负相关关系,而与北太平洋暖流区(25°—45°N,165°E—140°W)海温呈显著正相关关系。因此,建立了用于诊断和预测重灾区春季林火异常发生的判别指数FI。通过分析FI与北半球500 hPa高度场的关系,认为北太平洋海温异常通过持续性地影响欧亚中高纬地区环流异常,进而影响到重灾区春季林火的发生。     

Environmental impact of soil erosion under different cover and management systems

Runoff, soil loss and physical chemical composition of surface soil, runoff water and eroded sediment were measured for three erosive rainstorms of the 1988 Autumn-Winter season, on clay soil slopes (Typic Chromoxeret) under different cover and management systems in a locality of Sicily.Four years reconsolidated natural grass-sod (Avena fatua and Lolium tumulentum), natural grass-sod with implanted forage shrubs (Atriplex halimus) and natural grass-rod afforested with Pine trees (Pinus halepensis), reduced significantly runoff and soil loss in comparison with tilled fallow following four years durum wheat cultivation.While differences in runoff and soil loss between reconsolidated systems were not significant, the higher biomass yield (Stringi et al. 1991) and the better soil cover (Chisci et al. 1991) of the Atriplex system, increased O.M. content of the soil and prevented soil erosion under very intense rainstroms of the semiarid Mediterranean area.The comparison of textural and aggregate grain-size composition of surface soil and sediment confirmed that physico-mechanical composition of sediment detached and transported by over-land flow on clayey soils is better estimated by pseudo-textural grain-size composition of surface soil (Chisci et al. 1989) than from textural composition.Soil loss amounts, and O.M., N and P enrichment ratios, combined in a specifically devised Environmental Impact Index (EI), demonstrated the excellent environmental protection value of reconsolidation of arable soils. However, Pinus system was somewhat less efficient than Atriplex and good natural grass-sod systems.     

美国白蛾在中国的危险性评估研究

摘要：对入侵害虫美国白蛾Hyphantria cunea(Drury)进行危险性评估,可以了解其适生区分布与发生风险概率,对其监测与防治有重大意义。利用GARP（Genetic Algorithm for Rule-set Prediction Modeling System）生态位模型预测美国白蛾在中国的适生区,并应用信息扩散模糊数学方法,对河北省部分地区美国白蛾进行危险性评估。结果表明：美国白蛾发生灾害风险评估值随着灾害指数的增大而减小,美国白蛾在中国的适生区分布范围：21.20°N～46.33°N,97.80°E～132.11°E和36.81°N～41.8°5N,76.00°E～94.66°E(新疆的部分地区)。基于GARP生态位模型及信息扩散理论,针对入侵物种已知分布数据对其进行危险性评估,对害虫的监测、防治、预警提供依据,具有广泛的应用前景。     

海南铜鼓岭国家级自然保护区植被数量分类与排序

为了科学区分海南文昌铜鼓岭国家级自然保护区植被类型的组成群系,深入了解其群落特征与环境因子之间的相互关系,本研究通过在保护区内全方位随机取样,共64个样地（取样总面积：2.11 hm2）,采用PC-ORD5.0进行双向指示种分析法(TWINSPAN)分类,除趋势对应分析(DCA)排序和典范对应分析(CCA)排序,用CANOCO 4.5软件完成。结果表明：（1）应用TWINSPAN分类和DCA排序将铜鼓岭自然保护区64个样地分为11个群系,隶属滨海灌丛、山麓灌木林、热带常绿季雨矮林3种植被类型;（2）64个样地在DCA排序轴第1轴呈现了水分梯度的变化,第2排序轴上呈现的环境意义不明显,表明水分因子对该保护区植被类型的形成与分布起着决定性作用;（3）铜鼓岭海拔不高,最高峰仅338 m,但CCA排序结果显示,对排序贡献由大到小依次为：海拔、坡度、坡向,第1排序轴与海拔相关性最大,第2排序轴与坡度有很大的相关性,充分表明沿海基岩海岸环境与森林植被分布的特殊性。     

Effects of tillage,crop systems and fertilization on weed abundance and diversity in 4-year dry land winter wheat

The arable fields in central Spain have been dominated by cereal production, especially winter wheat. In this area, the defined action of weed management program requires a clear understanding of the factors and mechanisms conditioning weed community dynamics in agro systems. This study evaluated the effects of different agricultural management systems on the abundance and diversity of weed communities in winter wheat crops.Weed density and composition of weed species were sampled over four years; comparing monoculture wheat and rotational wheat in three agricultural management systems: (1) direct drilling (no-tillage, NT); (2) chisel ploughing (minimum tillage 15 cm depth, MT) and (3) mouldboard ploughing (traditional tillage 20 cm depth, CT). With the aim to be able to improve weed management in agro systems with semiarid environments; within each of the agricultural management systems, we examined the impact of mineral fertilization (traditional and balanced) as a tool for reducing the external inputs in arable cereals.Weed diversity was assessed using the three common diversity indices: Shannon's index, evenness index and species richness. The data collected showed total weed density was different per tillage system and each year of the study, but we did not find significant differences between crop systems over the study.The abundance, diversity and evenness of the weed community in the arable field, were significantly increased in NT systems. Within the direct drilling (NT) plots, rotational wheat showed the highest levels of weed infestation and diversity. Comparing traditional and balanced mineral fertilization of soil did not reveal a significant effect on weed abundance and diversity observed in field.     

棉纤维品质指标形成的动态模拟

棉纤维品质形成的准确模拟对构建棉花生长模拟系统及优质高产管理决策具有重要意义。本文以棉铃发育的生理生态过程为基础，采用生理发育时间作为定量发育进程的尺度，通过量化品种效应及水分、日均温和日温差等生态因子对棉纤维品质指标形成的影响，构建了预测棉纤维伸长、比强度增加和纤维素积累的模拟模型。利用不同生态点不同日均温和日温差条件以及不同水分处理的试验资料对模型进行了检验。结果显示，纤维长度、纤维比强度、纤维素含量模拟值与观测值之间的根均方差（RMSE）分别为1.15 mm，1.03 cN·tex^-1和4.37%，表明模型具有较好的预测性和适用性。     

Denitrification and nitrous oxide in the North Sea

In situ sediment denitrification rates were determined in the major areas of deposition of the North Sea, using the acetylene block technique. In addition, nitrous oxide profiles of the water column were determined. Nitrous oxide production generally occurred in the photic zone possibly due to nitrification; and throughout the water column in the German Bight region. Consumption at depth was possibly due to reduction in the anoxic microzones of faecal pellets, concentrated at the thermocline. Saturation of surface waters was 102.2% compared to 130.3% in the German Bight region. Calculated flux of nitrous oxide to the atmosphere was 9.5 × 10⁶ kg yr⁻¹, over half of which was produced in the German Bight.Sediment denitrification rates varied through three orders of magnitude; the highest value of 150 μmol m⁻² d⁻¹ was recorded in the Norwegian Trench. Nitrous oxide production by the sediments was low (1.1 μmol m⁻² d⁻¹ max.), and was undetectable at half of the sites. Sediment nutrient profiles exhibited porewater nitrate concentrations exceeding that of the overlying water suggesting that denitrification was fuelled by nitrification, which, in turn was related to other environmental variables. A significant positive relationship existed between in situ denitrification rate and the nitrate content of the upper sediment. Extrapolation of the rate to the total area of deposition in the North Sea suggests that denitrification is responsible for a minimum loss of 7.5–12% of the total annual nitrogen contaminant input.     

Path analyses of the influence of substrate composition on nematode numbers and on decomposition of stranded seaweed at an Antarctic coast

Large amounts of seaweed are deposited along the coast of Admiralty Bay, King George Island, Antarctica. The stranded seaweed partly decomposes on the beach and supports populations of meiofauna species, mostly nematodes. The factors determining the number of nematodes found in the seaweed packages were studied. Seaweed/sediment samples were collected from different locations, along the coast near Arctowski station, covering gradients of salinity, elevation and proximity of Penguin rookeries. On the same locations decomposition rate was determined by means of permeable containers with seaweed material. Models, including the relations between location, seaweed and sediment characteristics, number of nematodes and decomposition rates, were postulated and verified using path analysis. The most plausible and significant models are presented.The number of nematodes was directly correlated with the height of the location, the carbon-to-nitrogen ratio, and the salinity of the sample. Nematode numbers were apparently indirectly dependent on sediment composition and water content. We hypothesize that the different influences of melt water and tidal water, which affect both salinity and water content of the deposits, are important phenomena underlying these results.Analysis of the relation between decomposition rate and abiotic, location-related characteristics showed that decomposition rate was dependent on the water content of the stranded seaweed and sediment composition. Decomposition rates were high on locations where water content of the deposits was high. There the running water from melt water run-off or from the surf probably increased weight losses of seaweed.     

Comparison of the pigmentation of two strains of the prymnesiophyte Phaeocystis sp.

Two strains of Phaeocystis sp., one isolated from the Weddell Sea region (Antarctica) and one from the North Sea, were compared for their growth characteristics and pigmentation during growth in batch cultures. Experiments were performed starting with identical nutrient and light conditions at 2°C, 7°C and 10°C. Division rates ranged from 0.17 to 0.94 d⁻¹ depending on strain and temperature: the Antarctic strain grew fastest at 2°C (μ=0.71 d⁻¹), the strain from the North Sea at 10°C (μ=0.94 d⁻¹). Growth phase, phase in the diurnal cycle and temperature influenced the 19'hexanoyloxyfucoxanthin to chlorophyll a ratio in both strains. Large differences in this ratio were found between flagellates and colony cells from the same strain. Despite variability within each strain, mean levels of 19'hexanoyloxyfucoxanthin were always higher in the Antarctic strain. Another fucoxanthin-related pigment, 19'butanoyloxyfucoxanthin, showed the same trends during growth as 19'hexanoyloxyfucoxanthin in the antarctic strain but was undetectable in the strain isolated from the North Sea. A comparison was made with field data collected during the Phaeocystis blooming period in the coastal zone of the North Sea. During this period relative amounts of 19'hexanoyloxyfucoanthin as well as the absence of 19'butanoyloxyfucoxanthin matched with the results from the North Sea strain in culture. Environmental factors influence pigment content and ratio, yet the two investigated Phaeocystis strains can be distinguished on the basis of their pigment characteristics.     

Morpho-physiological traits characterizing environmental adaptation of Avena barbata

Seventeen morphological and physiological characteristics of three Avena barbata L. populations from Israel were measured in order to define possible combinations explaining adaptation of these populations to different precipitation, temperature and altitude regimes. Five genotypes from each A. barbata populations were collected from Ashqelon (31°63′N, low annual precipitation), En Hamifraz (32°46′N, high temperature), and Mount Carmel (32°73′N, high altitude), Israel. The behavior of the populations was followed by measuring the morpho-physiological characteristics under well-watered and moderately drought stressed conditions. The experiment was conducted at the Department of Plant Production, University of Helsinki, Finland (60°13′N). The measured traits characterized macro-morphology, transpiration rate, photosynthesis and chloroplast features. The data were subjected to principal component and discriminant analyses and the characteristic combinations that most adequately accounted for the differences among A.barbata populations were established. Differences among the populations were related to adaptation to low water availability and high altitude characterized by special light conditions. The Mount Carmel population (high water availability, high light intensities and increased proportion of UV-light) was characterized by higher tillering, hairy leaf sheaths, high transpiration, high stomatal conductance, slow fluorescence quenching capacity, and less starch granules per chloroplast when compared with populations adapted to lower altitudes. The En Hamifraz population (high mean temperature) was characterized by a high CO₂ exchange rate and both En Hamifraz and Ashqelon populations (both adapted to arid conditions) used water sparingly when moderately drought stressed. This revised version was published online in July 2006 with corrections to the Cover Date.     

大樱桃传粉昆虫的调查研究

为了探明大樱桃传粉昆虫的种类和数量。在山西省大樱桃主产区以样地调查法与定点网捕方式调查绛县申王坡村、史村的大樱桃花期传粉昆虫。结果表明：（1）采集标本3290头,经鉴定共分为4个目15个科26个种。在传粉昆虫中膜翅目占64.83%~74.81%,膜翅目传粉昆虫中以蜜蜂科为主;（2）β多样性分析显示,平川区和山区2个调查样地传粉昆虫群落相似性系数为0.63,沿着从山区到平川区环境梯度的变化,物种有相对减少趋向;（3）9:00-11:00为昆虫采集活动高峰时段,按一天中采集昆虫数量排序依次为蜜蜂、地蜂、食蚜蝇和条蜂;气温10℃时,开始有昆虫活动,最早出巢活动的昆虫为蜜蜂。大樱桃访花昆虫种类较多,膜翅目昆虫是大樱桃花期的主要传粉昆虫,山区传粉昆虫的物种较平川丰富。     

Dredging activities in the Dutch Wadden Sea: effects on macrobenthic infauna

Effects of dredging on macrobenthic infauna were studied at several sites and water depths in the estuarine Dutch Wadden Sea. Dredging in tidal flat areas was found to have long-lasting effects: filling-in rates in such areas were extremey slow, sediment composition altered dramatically and recovery of benthos was virtually absent during the long period of filling-in. Such pits on tidal flats persisted for more than 15 years. In subtidal areas recovery of bottom structure as well as the inhabiting infaunal benthos proceeded rapidly, while the original situation may be expected to return. In tidal channels with strong currentts both filling in and recolonization took only about 1 to 3 years. In some subtidal areas with low tidal stream velocities, such as tidal watersheds, recovery proceeded less rapidly: it lasted 5 to 10 years.     

Examination of the connection between the patchiness of benthic nutrient efflux and epiphytobenthos patchiness on intertidal flats

Intertidal epiphytobenthos activity (expressed in mmol oxygen evolution·m⁻²·h⁻¹) and nutrient efflux out of the sediment (computed from pore water nutrient concentration profiles and expressed in μmol·m⁻²·h⁻¹) were studied at the same places. Increased ammonia or phosphate efflux stimulated epiphytobenthos activity, and an optimum of epiphtobethos activity was observed when the molar N:P ratio in the efflux agreed with the N:P ratio in diatom biomass. It is concluded that epiphytobenthos patchiness depends on the spatial distribution of nutrient efflux and on the N:P ratio in the efflux. The conditions of nutrient efflux were further studied by fertilizing the sediment with urea and phosphate. Phosphate could be traced in the pore water over two months; ammonia over more than two months. The formation of a diatom bed at the fertilized are was observed once, but efforts to reproduce it failed, indicating the importance of other growth-determining conditions. Nutrient efflux was prevented by a plastic foil to stimulate a possible efflux inhibition by diatom mats. Concentrations below the foil were examined and compared with results from an untreated area. An increase of nutrient concentrations in the pore water was observed.     

Genetic Advances in Adapting Rice to a Rapidly Changing Climate

Rice, with its wide geographic distribution extending from 50°N to 35°S, is expected to be the most vulnerable cultivated crop to future changing climates. Among the different abiotic stresses, extreme temperatures coinciding with critical developmental stages, increasingly frequent floods and drought spells, and worsening sea water inundation are some of the major threats to sustainable rice productivity. Following the successful implementation of molecular marker‐assisted backcrossing to introgress large‐effect QTL for submergence tolerance in rice mega varieties, rice breeding for drought, salinity and, recently, heat tolerance is employing the same approach. Although tolerance for combined submergence and salinity has been achieved, developing rice varieties with multiple tolerance for other abiotic and biotic stresses and finding the appropriate agronomic package to exploit their performance remain a challenge. The major bottleneck is the lack of unidentified large‐effect QTL for other abiotic stresses that are strongly influenced by genotype × environment (G × E) interaction. Rapid advances in the use of molecular tools, including a plethora of SNP markers, are expected to facilitate the development of major abiotic stress‐tolerant rice. In response to the actual farmer field situation, progress achieved in understanding and developing independent abiotic stress tolerance is being exploited to combine tolerances (for example, heat and drought; salinity and submergence) to address emerging environmental problems across a wide range of rice ecosystems.