黄土高原白羊草、沙棘和辽东栎细根比根长特性

以黄土高原地区典型草本(白羊草)、灌木(沙棘)和乔木(辽东栎)为对象,研究了3种植物细根比根长在不同土层的分布状况以及与其它细根参数和土壤物理因子之间的相关性。结果表明,3种植物细根比根长的变化范围为6~55 mm/mg。在0~80cm土层,白羊草、沙棘和辽东栎细根比根长变化范围分别为18~55 mm/mg,14~40 mm/mg,6~33 mm/mg。3种植物0~80cm土层平均细根比根长从大到小依次为白羊草>沙棘>辽东栎。3种植物0~10cm土层细根比根长依次为沙棘>辽东栎>白羊草,10~80cm依次为白羊草>辽东栎>沙棘,表明3种植物细根比根长不仅在这两土层中的分布不具一致性,而且与0~80cm土层平均比根长也不具有一致性,进一步说明3种植物沿土壤剖面的生物量分配策略不同。相关分析表明,3种植物细根比根长与其它细根参数之间的相互关系各不相同,制约程度存在差异。与土壤物理因子的相关分析表明,3种植物细根比根长均随土壤含水量的增加而减少。土壤各级水稳性团聚体和土壤颗粒对3种植物细根比根长并无一致的影响。

芨芨草在黄土边坡治理中的应用效果

针对黄土高原铁路、公路、大坝及农田地埂边坡长期裸露的水土流失与生态环境问题,选择禾本科植物-芨芨草,进行了为期10年的引种、栽培、生理生态特性与水保等方面的综合开发利用研究。结果表明,芨芨草具有耐旱、耐盐碱、耐瘠薄、抗风沙和极强的固土护坡作用,采用的包衣穴播、分根栽植、基茎扦插3大栽培技术,使芨芨草植株在长期干旱裸露的边坡能快速形成密集的地上部分和发达的根系,固结土壤,防止地表径流冲刷土壤,保护了铁路、公路、大坝及农田地埂边坡的生态安全,为我国西部同类型区的边坡治理,提供了抗逆性较强的优良禾本科植物与配套的栽培技术体系。

子午岭不同土地利用方式对土壤性质的影响

通过野外调查和室内分析相结合的方法,研究子午岭次生林区不同土地利用方式下的土壤性质状况,分析土地利用状况与土壤质量之间的关系,结果表明:不同土地利用方式表层土壤有机质、全氮、全磷、pH值、脲酶、蔗糖酶和碱性磷酸酶含量或活性差异显著,农地主要土壤养分含量和酶活性较低,林地则较高。除pH值外,不同利用方式下土壤养分和酶活性均随土层深度的增加而逐渐减小。除土壤pH值外,不同利用方式下土壤有机质、全氮、全磷、铵态氮、脲酶、蔗糖酶、碱性磷酸酶和过氧化氢酶之间呈显著或极显著正相关性。以林地为对照的土壤退化指数表明农用地和撂荒翻耕地土壤质量退化显著,其表层(0～20cm)土壤退化指数分别为44.86%和43.10%;撂荒未翻耕地深层(20～130cm)土壤质量则有所提高。

黄土丘陵区农业可持续发展的科学途径

依据黄土丘陵区生态-经济系统演变过程中的正反两方面事例,分析了制约该区农业、经济可持续发展的主要限制因素,探讨了改善该区生态环境、实现农业持续发展的科学途径。并以此认为,退耕还林还草恢复林草植被,是实行农耕制度革命的重要举措,应该与产业结构调整密切结合,实现生态经济可持续发展。

施氮与基因型对半湿润区冬小麦灌浆期籽粒氮、磷累积的影响

在年均降水量632mm的黄土高原南部半湿润区红油土上以“9430”、“小偃6号”和“商188”为供试材料,研究了不施N和施N(90kg/hm2)条件下不同基因型冬小麦灌浆期间籽粒中N、P累积特性。结果表明,不同基因型冬小麦灌浆期间籽粒含N量呈现出“高-低-高”的时间变化趋势,而籽粒含P量基本呈直线下降趋势。不同基因型小麦籽粒最终含N量的高低与灌浆进程中籽粒含N量的高低一致,“小偃6号”籽粒含N量始终高于“商188”和“9430”。在整个灌浆期间,籽粒中N累积速率显著高于P累积速率,灌浆末期表现更为明显。籽粒N的活跃累积期与千粒重呈显著正相关,提高籽粒中N累积速率有利于增加籽粒蛋白质含量。基因型是控制籽粒中N活跃累积期和N活跃平均累积速率的主要因子,而基因型对籽粒P活跃累积期和平均累积P速率无显著影响。施N虽然对灌浆期间籽粒N、P累积参数无显著影响,但在一定程度上可以提高灌浆进程中籽粒含N量,对最终籽粒N累积具有一定的促进作用。

黄土丘陵区小流域系统生态经济要素分析——以宁夏隆德县李太平小流域为例

以隆德县李太平小流域为例,对比分析了退化小流域系统恢复重建过程中系统的生态经济要素变化,揭示系统演变趋势。应用能值方法分析了投入产出的动态变化,评价治理的生态经济效果。结果显示:农、林、牧业用地比例由1990年的6·2∶2·0∶1·0变为2003年的1·9∶1·4∶1·0,土地利用及种植结构趋于合理,农业产值所占比重由79·6%下降为54·8%,林业、牧业、副业产值比例分别由9·6%、9·6%、1·1%上升为22·7%、15·1%、7·4%,收入多样性指数也呈增加趋势,显示了流域收入构成的多元化,有利于生态经济系统的稳定。同时,恩格尔系数减小,表明人民生活水平日益提高。基于能值的流域生态经济系统投入产出效率动态研究结果表明在调整后的土地利用格局及种植结构下,净能值产出率由1990年的2·5增长到2003年的3·41,资源利用效率逐年提高,环境负荷率在1990、1995和2003年分别为2·55、2·44和2·11,呈减小趋势,能值持续性指数从1990年的0·98增加到2003年的1·62,经济与生态环境的协调性不断提高。研究结果表明该治理模式是成功的。

石佛寺水库对周围环境的影响

石佛寺水库对周围环境的影响裴铁，范世香，韩绍文，迟振文（中国科学院沈阳应用生态研究所，１１００１５）王鉴成（辽宁省水利电力厅，沈阳１１０００３）ＩｍｐａｃｔｓｏｆＳｈｉｆｏｓｉＲｅｓｅｒｖｏｉｒｏｎＩｔｓＡｄｊａｃｅｎｔＥｃｏｌｏｇｉｃａｌＥｎｖｉｒ...

试论景观规划的目标、任务和基本原则

试论景观规划的目标、任务和基本原则肖笃宁李晓文（中国科学院沈阳应用生态研究所，１１００１５）ＯｎｔｈｅＴａｒｇｅｔａｎｄＰｒｉｎｃｉｐｌｅｓｏｆＬａｎｄｓｃａｐｅＰｌａｎｎｉｎｇ．ＸｉａｏＤｕｎｉｎｇ，ＬｉＸｉａｏｗｅｎ（ＩｎｓｔｉｔｕｔｅｏｆＡｐ?..

15个乙烯-乙烯基化合物共聚物的取代基参数

本文应用取代基参数(SCS)方法处了15个EV共聚物的~(12)C NMR谱.它们是:(1)乙烯-α-烯烃共聚物,即乙烯-丙烯共聚物.乙烯-丁烯-1共聚物,乙烯-4-甲基-1-戊烯共聚物,乙烯-己烯-1共聚物和乙烯-辛烯-1共聚物;(2)乙烯-含氧乙烯基共聚物,即乙烯-甲基丙烯酸N,N-二甲基胺乙酯共聚物,乙烯-丙烯酸甲酯共聚物.乙烯-丙烯酸共聚物,乙烯-乙酸乙烯酯,乙烯-乙烯醇,乙烯-氧化碳共聚物(ECO)(?)乙烯-卤代乙烯共聚物及其它EV共聚物,即乙烯-氯化乙烯共聚物(包含氯化聚乙烯),乙烯-溴化乙烯共聚物,乙烯-苯乙烯共聚物(包含氢化丁二烯-苯乙烯共聚物)和乙烯-丙烯腈共聚物、得到了15种取代基的SCS参数.

Dietary-morphological relationships of fishes in Liangzi Lake, China

Species in Liangzi Lake were clustered into four trophic groups: Hemiramphus kurumeus and Hemiculter bleekeri bleekeri fed predominantly on terrestrial insects; Carassius auratus auratus and Abbottina rivularis on non-animal food; Hypseleotris swinhonis, Ctenogobius giurinus, Pseudorasbora parva and Toxabramis swinhonis on cladocerans or copepods; Culterichthys erythropterus on decapod shrimps. Gut length, mouth width, mouth height, gill raker length and gill raker spacing, varied widely among species. With the exception of three species pairs (H. swinhonis, C. glurinus; C. erythropterus, H. kurumeus; T. swinhonis, H. bleekeri bleekeri), principal components analysis of morphological variables revealed over-dispersion of species. Canonical correspondence analysis of dietary and morphological data revealed five significant dietary-morphological correlations. The first three roots explained > 85% of the total variance. The first root reflected mainly the relationship of gut length to non-animal feud, with an increase in gut length associated with an increase in non-animal food. The second root was influenced strongly by the relationship of the gill raker spacing to consumption of copepods, with an increase in gill raker spacing associated positively with copepods in the diet. The third root was influenced by the relationship of mouth gape to consumption of fish and decapod shrimps, with an increase in mouth gape associated with more fish and decapod shrimps in the diet. These significant dietary-morphological relationships supported the eco-morphological hypotheses that fish morphology influence food use, and morphological variation is important in determining ecological segregation of co-existing fish species. (C) 2001 The Fisheries Society of the British Isles.

渤黄海沉积物中的多环芳烃和多氯联苯及其与生态环境的耦合解析

海洋沉积环境中多氯联苯（PCBs）和多环芳烃（PAHs）的研究对于揭示其污染历史、来源途径、迁移转化以及评价其对环境的潜在生态风险都有重要的科学意义和应用价值，本研究选择我国典型近海中比较开阔的南黄海和受人为影响严重的渤海湾沉积物中的PAHs和PCBs作为主要研究对象，结合对生态环境对应关系的剖析，系统研究了沉积物中PAHs和PCBs的地球化学分布特征、影响控制因素、演变趋势、潜在生态风险等，获得了以下系统的认识： 1.南黄海表层沉积物中多环芳烃和多氯联苯的分布与沉积类型及模式相一致，受控于“沉积类型-动力过程-来源途径”。PCBs含量（范围：518～5848 pg/g，平均值：1715 pg/g）低于受人为影响严重的长江口、珠江口和渤海，分布具有中部海区＞东部海区＞西部海区的特征；PCBs随着沉积物粒径的减小和粘土含量的增加而增加，且与总有机碳（r=0.61，p＜0.01）含量呈显著线性正相关，表明PCBs在沉积物中的分布受控于被水动力过程原动力控制的沉积类型与沉积模式。 2. 1914～2004年间，南黄海沉积物中PAHs和PCBs的变化比较显著，在时间序列上经历了三个明显的不同阶段。近90年来，PAHs和PCBs在柱状样中垂直分布随深度的增加而降低，即近年南黄海沉积物中PAHs和PCBs的残留水平比上世纪初明显增加。其中1914～1932年间，PAHs和PCBs保持在较低的水平；1932～1962年间，PAHs和PCBs的含量发生急剧的变化，在1932～1944和1956～1962年两个时间段，PAHs和PCBs的含量达到峰值；自1962年至今，PAHs和PCBs呈稍有增加趋势。PAHs的组成和特征组分比值分析显示，1920～1944年间PAHs主要来自石油产品泄漏，1944～1980年间，主要来自草/木材/煤燃烧，1980年至2004年则显示出石油和燃烧产物混合来源的特征。 3.渤海湾沉积物中的PAHs、PCBs、DDTs和HCHs的分布模式不同，反映了这四种污染物的地球化学行为存在着明显的差异性。PAHs、PCBs、DDTs和HCHs的含量范围为149.0～393.4 ng/g，360.8～1728.3 pg/g，462.2～2007.3 pg/g和4.31～33.8 ng/g。马颊河口、海河口和黄河口附近的海区的沉积物中PAHs和PCBs的含量显著高于渤海湾内其它站位，DDTs在湾外沉积物中的含量大于湾内，在海河口附近站位测得HCHs含量的最高值，在其它站位其浓度变化不大。PAHs特征成分的比值显示渤海湾沉积物中PAHs主要来源于草/木材/煤燃烧的产物经过大气的输运过程进入水体；DDTs和HCHs的组成显示，在DDTs和HCHs被禁用后仍有新的输入源。 4.南黄海沉积物POPs总体水平不高，其环境污染危害和潜在生态风险不大，从沉积物POPs的角度来说南黄海的环境质量较好。潜在生态危害指数评价表明，渤海湾沉积物中芴可能会产生潜在的生态风险，DDTs和HCHs的含量低于一类沉积物质量标准值，总体而言，其沉积物质量良好，潜在生态风险较低。 论文的创新性点在于：1）首次研究了近百年南黄海沉积物中多环芳烃和多氯联苯的演变趋势，判断了其来源并对近百年二者的潜在生态风险进行评价。2）系统剖析了南黄海及渤海湾的生态环境与PAHs和PCBs的耦合关系，对阐明POPs的毒理效应有重要的科学意义。3）系统解析了渤海湾沉积物中PAHs，DDTs和HCHs的污染现状，来源和迁移途径，可为科学开发和利用渤海海域提供重要的理论依据。

Diurnal, seasonal and annual variation in net ecosystem CO2 exchange of an alpine shrubland on Qinghai-Tibetan plateau

Thus far, grassland ecosystem research has mainly been focused on low-lying grassland areas, whereas research on high-altitude grassland areas, especially on the carbon budget of remote areas like the Qinghai-Tibetan plateau is insufficient. To address this issue, flux of CO2 were measured over an alpine shrubland ecosystem (37 degrees 36'N, 101 degrees 18'E; 325 above sea level [a. s. l.]) on the Qinghai-Tibetan Plateau, China, for 2 years (2003 and 2004) with the eddy covariance method. The vegetation is dominated by formation Potentilla fruticosa L. The soil is Mol-Cryic Cambisols. To interpret the biotic and abiotic factors that modulate CO2 flux over the course of a year we decomposed net ecosystem CO2 exchange (NEE) into its constituent components, and ecosystem respiration (R-eco). Results showed that seasonal trends of annual total biomass and NEE followed closely the change in leaf area index. Integrated NEE were -58.5 and -75.5 g C m(-2), respectively, for the 2003 and 2004 years. Carbon uptake was mainly attributed from June, July, August, and September of the growing season. In July, NEE reached seasonal peaks of similar magnitude (4-5 g C m(-2) day(-1)) each of the 2 years. Also, the integrated night-time NEE reached comparable peak values (1.5-2 g C m(-2) day(-1)) in the 2 years of study. Despite the large difference in time between carbon uptake and release (carbon uptake time < release time), the alpine shrubland was carbon sink. This is probably because the ecosystem respiration at our site was confined significantly by low temperature and small biomass and large day/night temperature difference and usually soil moisture was not limiting factor for carbon uptake. In general, R-eco was an exponential function of soil temperature, but with season-dependent values of Q(10). The temperature-dependent respiration model failed immediately after rain events, when large pulses of R-eco were observed. Thus, for this alpine shrubland in Qinghai-Tibetan plateau, the timing of rain events had more impact than the total amount of precipitation on ecosystem R-eco and NEE.

Depression of net ecosystem CO2 exchange in semi-arid Leymus chinensis steppe and alpine shrub

Uptake and release of carbon in grassland ecosystems is very critical to the global carbon balance and carbon storage. In this study, the dynamics of net ecosystem CO2 exchange (FNEE) of two grassland ecosystems were observed continuously using the eddy covariance technique during the growing season of 2003. One is the alpine shrub on the Tibet Plateau, and the other is the sem-arid Leymus chinensis steppe in Inner Mongolia of China. It was found that the FNEE of both ecosystems was significantly depressed under high solar radiation. Comprehensive analysis indicates that the depression of FNEE in the L. chinensis steppe was the results of decreased plant photosynthesis and increased ecosystem respiration (R-eco) under high temperature. Soil water stress in addition to the high atmospheric demand under the strong radiation was the primary factor limiting the stomatal conductance. In contrast, the depression of FNEE in the alpine shrub was closely related to the effects of temperature on both photosynthesis and ecosystem respiration, coupled with the reduction of plant photosynthesis due to partial stomatal closure under high temperature at mid-day. The R,c of the alpine shrub was sensitive to soil temperature during high turbulence (u* > 0.2 m s(-1)) but its FNEE decreased markedly when the temperature was higher than the optimal value of about 12 degrees C. Such low optimal temperature contrasted the optimal value (about 20 degrees C) for the steppe, and was likely due to the acclimation of most alpine plants to the long-term low temperature on the Tibet Plateau. We inferred that water stress was the primary factor causing depression of the FNEE in the semi-arid steppe ecosystem, while relative high temperature under strong solar radiation was the main reason for the decrease of FNEE in the alpine shrub. This study implies that different grassland ecosystems may respond differently to climate change in the future. (c) 2006 Elsevier B.V All rights reserved.

Cigarrinhas-das-pastagens.

Várias espécies de cigarrinhas (Hemiptera: Cercopidae) são importantes pragas de pastagens na América tropical. Esses insetos podem diminuir drasticamente a disponibilidade e a qualidade de gramíneas forrageiras, reduzindo a capacidade de suporte das pastagens. Milhões de hectares estabelecidos com várias cultivares do gênero Brachiaria têm sofrido sensíveis perdas ocasionadas por esse grupo de insetos. Apesar de tamanha importância econômica, muito ainda há por ser feito no que se refere às pesquisas com as cigarrinhas-das-pastagens. Tal sistema inseto-planta é complexo. Ele engloba um diverso grupo de espécies de cigarrinhas associado a um diverso grupo de espécies de gramíneas forrageiras que, por sua vez, resultam em pastagens que podem ter idades diferentes e estarem sob diferentes sistemas de manejo, em ampla variedade de condições ecológicas. Esforços de controle têm sido concentrados na área de resistência de plantas a insetos, alternativa reconhecida como de baixo custo e de fácil adoção pelos produtores. Trata-se, provavelmente, da melhor opção de controle para culturas de baixo valor por unidade de área, como as pastagens, geralmente estabelecidas em extensas áreas. A seleção de gramíneas resistentes às cigarrinhas tem sido conduzida e plantas promissoras identificadas. É importante, entretanto, que estudos adicionais sobre a biologia e a eco logia desses insetos, com avaliações de alternativas de controle, sejam realizados. Algumas dessas medidas de controle, assim como necessidades de pesquisa, são discutidas.

Um história desconhecida e supreendente da Amazônia.

2007