松嫩平原优势种羊草与其主要伴生种芦苇空间分布格局分析

芦苇是松嫩草地优势种羊草的主要伴生种,两者常常形成物种组成比较单一的混生群落或者与其他物种组成羊草 杂类草群落.选择羊草 芦苇混生群落,羊草群落和芦苇群落的交错区进行羊草、芦苇单物种格局分析.结果表明,1)混生群落和交错区中,羊草和芦苇均是以集聚分布的形式存在;2)羊草在混生群落中的格局强度小于交错区中的格局强度,芦苇在2种类型群落中的格局强度没有显著差异;3)除了考虑物种的生物学特性以外,混生群落种内、种间竞争也是影响羊草集聚分布和格局强度的主要因素,交错区中,环境异质性和种间竞争是影响集聚分布和格局强度的重要因子;4)芦苇在混生群落和交错区中格局强度没有明显差异,由此可以判定芦苇的空间分布格局形成主要受植物本身生物学特性的影响.     

芦苇和白刺空间格局对青土湖生态输水的响应

石羊河尾闾湖——青土湖位于腾格里沙漠和巴丹吉林沙漠边缘,是阻隔两大沙漠合围的生态屏障。自2010年开始连续5年向青土湖进行生态输水并形成一定规模的水面,对促进区域植被恢复和保护民勤湖区绿洲具有重要的生态意义。本研究选用2008年、2010年、2011年、2012年、2013年、2014年的高分辨率遥感影像资料同时结合研究区的实地调查资料,对形成人工水面的面积和输水前后的芦苇(Phragmites australis)、白刺(Nitraria tangutorum)群落面积进行了统计分析和对比。结果表明,5年连续输水形成叠加效应,水面面积成倍增加,芦苇相对频度逐年增加和白刺相对频度逐年减少,芦苇群落(Form.P.australis)面积增加了8.43倍,临接水域和水域中的白刺群落(Form.N.tangutorum)消失,白刺面积减少了68.00%。人工输水促进了芦苇群落依水蔓延,镶嵌于水域成片分布;距水面50 m范围的白刺群落由连续成片成点状。输水促进了湿生植物生长,导致荒漠植物种退化。     

黄河口生态恢复工程对湿地土壤不同形态无机硫动态变化的影响

选择黄河口生态恢复前后的未恢复区（R₀）、2007年恢复区（R₂₀₀₇）和2002年恢复区（R₂₀₀₂）的芦苇湿地为研究对象，探讨了生态恢复工程对生长季湿地土壤无机硫形态变化的影响。结果表明，生态恢复工程不同程度地改变了湿地土壤中各形态无机硫含量。相对于R₀，R₂₀₀₂和R₂₀₀₇土壤中的水溶性硫（H₂O—S）含量分别降低46.7%和44.7%，吸附性硫（Adsorbed—S）和盐酸可溶性硫（HCl—Soluble—S）含量分别增加0.4%，116.0%和50.1%，29.1%，而盐酸挥发性硫（HCl—Volatile—S）含量在R₂₀₀₂下降8.0%，在R₂₀₀₇增加19.7%。不同恢复阶段湿地土壤中各形态无机硫含量在生长季呈不同的变化特征，这一方面与不同湿地植物生长节律以及地上与地下之间的硫养分供给关系密切相关；另一方面则与不同生态补水方式导致的环境因子，尤其是pH、EC和氮养分的变化有关。随着恢复年限的增加，湿地土壤的总无机硫（TIS）含量以及其占全硫（TS）含量的比例均呈降低趋势。湿地土壤的TIS储量整体随恢复年限的增加而降低，而这种降低主要取决于H₂O—S、Adsorbed—S和HCl—Soluble—S的贡献，且以H₂O—S占优（78%~80%）。研究发现，随着黄河口湿地的逐渐恢复以及每年冬季芦苇收割活动的进行，恢复湿地土壤中的无机硫养分逐渐趋于缺乏状态，长期来看将不利于维持湿地的稳定与健康。     

新靶标铁苋菜在除草化合物筛选研究中的应用

铁苋菜具有特殊的生物学特性,属于旱田难防杂草。采用商品化除草剂硝磺草酮及巴佰金对铁苋菜进行室内防除试验,同时验证与硝磺草酮及巴佰金结构类似的新化合物对其的防除活性。结果表明,结构类似的除草化合物对铁苋菜的防除活性较为接近;铁苋菜作为新的生测靶标,可应用于化合物除草活性生测筛选研究。     

不同刈割时间收获后的羊草、芦苇水分和呼吸的变化

以多年生草本植物羊草和芦苇为实验材料,研究1d中不同时间（9∶00、13∶00、17∶00）刈割后含水量、气孔导度及呼吸速率的变化。结果表明：（1）羊草、芦苇刈割后水分散失均经历三个阶段：快速失水1d,缓慢失水2～3d,平稳期1d。芦苇叶片呼吸速率下降快,刈割5h后呼吸微弱,接近死亡;羊草叶片呼吸速率下降慢于芦苇,刈割7h后仍存在生理活动;（2）依据水分散失和呼吸代谢指标,三个刈割时间中,9∶00刈割能最大程度地减少干草调制过程中的养分损失,有益于制作优质干草。     

Predicting the age of fish using general and generalized linear models of biometric data: A case study of two estuarine finfish from New South Wales, Australia

Direct ageing of fish can be a laborious and expensive task when age estimates from a large population are required, and often involves a degree of subjectivity. This study examined the application of general and generalized linear models that predict the age of fish from a range of efficiently and objectively measured covariates. The data sampled were from yellowfin bream (Acanthopagrus australis (Sparidae) (Owen, 1853)) and sand whiting (Sillago ciliata (Sillaginidae) Cuvier, 1829) populations from New South Wales, Australia. The covariates evaluated in the models were fish length, otolith weight, sex and location (the estuary from which the fish were sampled). Akaike Information Criteria were used for model selection and residual plots of the final models revealed a satisfactory fit to the observations. The best fitting model for each species included all covariates. An additional investigation considered whether general and generalized linear models that predict age from two different categories of biometric information outperform age-length keys with respect to subsequent estimates of total mortality from catch-curve analysis. The two categories of biometric information differed in the ease and cost with which the information could be collected. The first category only included fish length and location as covariates, whilst the second category also included otolith weight and sex. It was found that traditional age-length keys outperformed the predictive models that estimated age from only fish length and location, because the results from the models were prone to significant bias. However, when otolith weight and sex were added as covariates to the predictive models, some of them, including a generalized linear model with a Poisson-distributed response variable, performed similarly to the age-length key. Given that otolith weight and the sex of fish are cheaper to quantify than age from a sectioned otolith in many situations, general or generalized linear models may represent a cheaper and faster method of estimating mortality compared to age-length keys. Such models can also easily incorporate the influence of spatial, temporal and demographic variation.     

中国芦苇研究现状与趋势

芦苇Phragmites australis为多年生高大草本植物,是世界广布的重要湿地物种,具有广泛的适应性及形态变异,并有极高的生态学和社会经济学价值。本文通过对近10年来中国各地对于芦苇研究的成果文献进行统计分析,揭示出我国芦苇研究的现状与趋势。     

铁苋菜提取物对仔猪生长性能、血液生化指标及肠道菌群的影响

目的:本试验旨在研究铁苋菜提取物对仔猪生长性能、血液生化指标及粪样菌群的影响.方法:选取同一批次的25日龄健康的外三元断乳仔猪120头,平均体重为9.60+0.65 kg/头,随机分为4组,每组3个重复,每个重复10头,公母各半;试验组分别为铁苋菜提取物组Ⅰ和组Ⅱ、抗生素组及对照组,铁苋菜提取物组Ⅰ和组Ⅱ在基础日粮中分...     

Growth patterns of reed (Phragmites australis): the development of reed stands in carp ponds

Reed stands exhibit apparent differences of stem diameter, shoot length, density, and invasiveness. In carp ponds, five characteristic growth patterns can be distinguished. These growth patterns are ontogenetic states of a time-dependent stand development. Invasive reeds with short shoots are found in newly occupied habitats. With continuing establishment of the stand, the shoots in the inner regions become taller and fewer, a growth pattern described as central reed. Later, only a few shoots with thick stems remain. Two alternative pathways of stand development exist: steep shore reed and reed tussocks. By mowing, the directional development of reed stands can be turned into a circulation of growth patterns. The growth patterns have implications for the selection of reed stand areas for conservation purposes.     

芦苇对空心莲子草从陆生环境向水生环境扩散的影响

[目的]探讨芦苇种植对空心莲子草从陆生境向水生境扩散的影响。[方法]模拟河岸带芦苇与空心莲子草生长状态,比较混种和控制条件下空心莲子草扩散及生物量变化。[结果]与控制条件下相比,芦苇种植使空心莲子草在陆生境纵向（沿陆地向水中的方向）与横向（与纵向垂直）扩散日变化率显著下降（P〈0．05）;水生境中均未出现显著差异;陆生境中横向和纵向扩散符合指数生长模型：Y=ae^bx＋y0;根生物量显著下降,达到50％;茎生物量下降16％,但其占比却上升62％。[结论]芦苇存在时,陆生境空心莲子草所受到的抑制要强于水生境;空心莲子草会通过提高其地上生物量占比,对芦苇抑制做出反应,以获取更多的光照。