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1.
环境因素对原生动物群落特征的影响   总被引:9,自引:1,他引:8  
1999年12月至2000年11月,对华中科技大学华瑜池的原生动物群落进行了研究,共检出原生动物125种,其中植鞭毛虫19种,动鞭毛虫28种,纤毛虫64种,肉足虫14种,对原生动物群落结构和功能的研究表明:1)自然条件下,PFU原生动物群落的种类组成数及原生动物群落的群集速度相对稳定;2)自然条件下,PFU原生动物群落结构和功能不受季节变化的影响;3)当PFU原和动物群落受到外界胁迫时,不管这种胁迫来自物化因素或是生物因素,其群落结构和功能都会发生破坏性变化;4)用PFU法进行原生动物群落生态学和毒理学研究,所得的结构参数及功能参数能反映客观状况,具有环境现实意义。  相似文献   

2.
鸭儿湖地区在上世纪60—70年代有机氯农药(OCPs)污染严重,为了改善水质1975年鸭儿湖开展了水质污染处理,并于2003年和2004年开展了清淤工作.为了解现阶段鸭儿湖地区有机氯农药污染状况,本文于2009年采集了鸭儿湖5个氧化塘20个表层沉积物,对有机氯农药残留进行了研究.利用气相色谱-质谱联用法(GC-MS)对...  相似文献   

3.
分别在 2 0 0 1年和 2 0 0 2年用国家标准《水质 -微型生物群落监测 -PFU法》在香港米浦自然保护区的基围塘和红树林中监测水质 .在 3个基围塘中共鉴定出 91种原生动物 ,为香港地区的首次记录 .同时在群落级水平上分析了4种生态结构参数和 5种功能参数 .用化学的方法成功地监测出在此 3个基围塘的PFU挤出液中 pp′-DDE和PCB的浓度 ,并且获得两年一致性的结果 .本文化学和生物学结合的研究结果为测定水中超痕量持久性有机污染物 (POPs)的环境暴露与生态毒性提供了一种新的尝试 .图 3表 8参 2 7  相似文献   

4.
锐劲特对原生动物群落的急性毒性试验   总被引:8,自引:0,他引:8  
以PFU法采集的淡水原生动物群落为试验对象 ,对锐劲特的急性毒性进行研究 .结果表明 ,锐劲特对原生动物群落的 48h LC50 为 35 83mg·l- 1 ;原生动物群落结构参数和功能参数随加入锐劲特的量而变化 ;在种类组成上 ,虽然鞭毛虫、纤毛虫、肉足虫的种类均随着毒物浓度的增大而下降 ,但是其减少的程度各不相同 ,纤毛虫所受损伤最大 ;在试验浓度范围内 ,功能类群发生显著变化 ,光合作用自养者和食藻者原生动物的物种逐渐消失 ,而一些食菌 碎屑类原生动物具有较高的耐受性 ,随着锐劲特浓度的增加 ,其在群落中的优势度更加明显  相似文献   

5.
环境砷污染是一个全球性问题.研究砷的生物地球化学循环可以明确环境中砷的来源及其转化特征,为探索砷污染治理的方法提供参考.越来越多的研究表明,自然界中的微生物在砷的迁移转化过程中发挥了重要作用.根据微生物对砷的代谢机制不同将其分为:砷氧化微生物、砷还原微生物和砷甲基化微生物.砷氧化微生物可以将环境中的As(Ⅲ)氧化为毒性较弱并且容易被铁铝矿物吸附固定的As(Ⅴ),因此对降低环境中的砷毒性具有重要作用;微生物对砷的甲基化作用的产物通常为毒性较低的有机砷,因此也被认为是理想的修复环境砷污染的生物手段之一;然而在还原环境中,砷还原微生物却可以将游离态和结合态的As(Ⅴ)还原为毒性更强的As(Ⅲ),从而加重环境中的砷污染状况.由此可见,明确微生物的砷代谢机制及其对砷污染环境中砷迁移转化的影响,是实现生物修复砷污染环境的必要前提.论文总结了近年来国内外微生物砷代谢机制的研究进展,以期为深入研究微生物代谢砷的机理及其在砷污染治理中的应用提供参考.  相似文献   

6.
活性污泥运转效能的生物监测   总被引:12,自引:0,他引:12  
讨论了θ/℃,pH,ρ(BOD)/mgL^-1,ρ(COD)/mgL^-1,ρ(SS)/mgL^-1,ρ(N)/mgL^-1,ρ(P)/mgL^-1,w(Cu^2 )/10^-6等几个影响活性污泥状况的理化因素,认为必须调节均化进水的水质水量,并调控污泥龄,回流比,曝气量等各种运行参数,分析了活性污泥的生理,生化监测法及运用细菌,藻类,原生动物,后生动物所进行的生物监测,提出通过监测原生动物群落动态是判断活性污泥运行效能的一种较简便准确的方法,比较了斑点杂交法(dot blot hybrid-ization),最大机率法(most probable number methods,MPNM),抗体(antibody)法和荧光原位杂交(fluorescent in situ hy-bridization,FISH)法检测氨氧化菌(ammonia-oxidizing bacteria)数量的效果,表明斑点杂交法具有高的准确度,并能检测出较低密度的细菌,MPNM低估了细菌数量,抗体法有高估细菌数的可能,FISH法对氨氮含量高的活性污泥混合液检测结果较好,但对低氨氮含量污水厂出水和河水的检测效果不佳。  相似文献   

7.
铁氨氧化(Feammox)是一种以廉价、易得的铁作为微生物电子供体的新型自养生物脱氮技术,即Fe(Ⅲ)还原与厌氧氨氧化的结合工艺,拥有成本低廉、无需有机碳源、污泥产量小、无温室气体产生等优势,是污水处理的一种潜在脱氮途径.本文对铁氨氧化反应的机理、功能菌种的种类和特性及电子穿梭体对其的影响进行了介绍,总结了铁氨氧化在污水环境中的脱氮效果及其与厌氧氨氧化、硝酸盐依赖型亚铁氧化和生物电化学系统的耦合技术,并指出目前铁氨氧化的应用问题及该技术未来的研究方向和重点可能是菌分离纯化、工艺参数控制.  相似文献   

8.
为减少滩涂养殖中的石油烃污染危害、提高水产品的品质,以珠江口滩涂红树林种植–养殖系统耦验示范研究基地A、B两系统的7个红树种植–养殖塘[包括桐花树(Aegiceras corniculatum)、木榄(Bruguiera gymnorhiza)、秋茄(Kandelia candel)、红海榄(Rhizophora stylosa)的单种或组合种植]为对象,采用荧光分光光度法监测了水体、底质及吊养的近江牡蛎(Ostrea rivularis)肉质的石油烃含量.结果表明,牡蛎体内石油烃含量在11.10~29.3 mg/kg之间;与水体中石油烃含量呈正相关(r=0.88),牡蛎能很好地指示水体水质状况.单种或组合种植秋茄、桐花树、木榄、红海榄4种红树植物能有效降低水体石油烃含量,与对照相比降幅为50%~80%;使牡蛎的石油烃含量受到不同程度的影响,与对照相比,红树种植塘牡蛎石油烃含量降幅在20%~60%不等.木榄和桐花树种植塘中,牡蛎中石油烃平均含量分别为11.20 mg/kg、14.13 mg/kg,能达到无公害水产品标准.因此红树种植–养殖塘具有"种植岛基质–红树植物–微生物"的协同效应,通过物理、化学和生物的共同作用降低了水体石油烃的含量,从而提高了养殖生物的品质.  相似文献   

9.
锑作为一种具有毒性和致癌性的类金属,其不合理的开发造成了严重的生态环境污染,尤其是土壤中高浓度锑和砷污染导致了环境中多种营养元素的缺乏。其中,氮素的缺乏严重阻碍了环境的恢复。然而,固氮微生物不仅能为氮素匮乏环境提供稳定的氮素来源,而且其固氮潜能可以作为监测土壤金属污染的敏感指标。为此,该文通过乙炔还原法(ARA)微宇宙培养试验手段,研究了不同价态锑和砷(三价及五价)在不同质量浓度(100、200、500、1 000、2 500、5 000 mg·L^-1)水平下对棕色固氮菌固氮潜能的影响,同时进一步探究了土壤固氮菌群落固氮潜能对土壤中主要锑和砷价态[Sb(Ⅴ)和As(Ⅴ)]的响应机制。结果表明,锑和砷浓度与棕色固氮菌和土壤固氮微生物的固氮潜能均呈显著负相关,验证了以固氮微生物固氮潜能作为生物指示物的可行性。此外,Sb(Ⅴ)对土壤固氮微生物的毒性显著小于As(Ⅴ)。三价锑和砷污染对固氮菌固氮潜能的毒性高于五价[As(Ⅲ)>Sb(Ⅲ)>As(Ⅴ)>Sb(Ⅴ)],这可能是由于Sb(Ⅲ)和As(Ⅲ)对细胞的致裂性强于Sb(Ⅴ)和As(Ⅴ)。相较于Sb(Ⅴ)和As(Ⅴ)对于棕色固氮菌固氮潜能的抑制作用,其对土壤固氮菌群落的固氮潜能的影响相对较弱。这一差异可能是由于土壤复杂的理化性质以及微生物群落和功能多样性而导致的。  相似文献   

10.
浮床栽培蕹菜根际脱氮微生物研究   总被引:2,自引:0,他引:2  
浮床栽培植物是一种利用植物根系的吸收和根际微生物作用来改善水质的生物修复技术.本研究以温棚内浮床栽培蕹菜试验为基础,采用PFU法定期监测脱氮细菌变化情况,并与水中总氮含量进行对比,分析在浮床栽培植物情况下脱氮细菌的特征及其与水中总氮含量变化的关系,结果表明:1)栽培蕹菜有利于脱氮细菌的稳定生长;2)脱氮细菌的生长与总氮的去除有良好的相关性.研究为浮床栽培植物净化水质提供了理论依据,对该技术的推广应用有一定的理论和现实意义.表5,参10.  相似文献   

11.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

12.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

13.
Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.  相似文献   

14.
Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.  相似文献   

15.
Effects of Coffee Management on Deforestation Rates and Forest Integrity   总被引:1,自引:0,他引:1  
Knowledge about how forest margins are utilized can be crucial for a general understanding of changes in forest cover, forest structure, and biodiversity across landscapes. We studied forest‐agriculture transitions in southwestern Ethiopia and hypothesized that the presence of coffee (Coffea arabica)decreases deforestation rates because of coffee's importance to local economies and its widespread occurrence in forests and forest margins. Using satellite images and elevation data, we compared changes in forest cover over 37 years (1973–2010) across elevations in 2 forest‐agriculture mosaic landscapes (1100 km2 around Bonga and 3000 km2 in Goma‐Gera). In the field in the Bonga area, we determined coffee cover and forest structure in 40 forest margins that differed in time since deforestation. Both the absolute and relative deforestation rates were lower at coffee‐growing elevations compared with at higher elevations (?10/20% vs. ?40/50% comparing relative rates at 1800 m asl and 2300–2500 m asl, respectively). Within the coffee‐growing elevation, the proportion of sites with high coffee cover (>20%) was significantly higher in stable margins (42% of sites that had been in the same location for the entire period) than in recently changed margins (0% of sites where expansion of annual crops had changed the margin). Disturbance level and forest structure did not differ between sites with 30% or 3% coffee. However, a growing body of literature on gradients of coffee management in Ethiopia reports coffee's negative effects on abundances of forest‐specialist species. Even if the presence of coffee slows down the conversion of forest to annual‐crop agriculture, there is a risk that an intensification of coffee management will still threaten forest biodiversity, including the genetic diversity of wild coffee. Conservation policy for Ethiopian forests thus needs to develop strategies that acknowledge that forests without coffee production may have higher deforestation risks than forests with coffee production and that forests with coffee production often have lower biodiversity value. Efectos de la Administración Cafetalera sobre las Tasas de Deforestación y la Integridad de los Bosques  相似文献   

16.
Abstract: The last century has seen the ascendance of a core economic model, which we will refer to as Walrasian economics. This model is driven by the psychological assumptions that humans act only in a self‐referential and narrowly rational way and that production can be described as a self‐contained circular flow between firms and households. These assumptions have critical implications for the way economics is used to inform conservation biology. Yet the Walrasian model is inconsistent with a large body of empirical evidence about actual human behavior, and it violates a number of basic physical laws. Research in behavioral science and neuroscience shows that humans are uniquely social animals and not self‐centered rational economic beings. Economic production is subject to physical laws including the laws of thermodynamics and mass balance. In addition, some contemporary economic theory, spurred by exciting new research in human behavior and a wealth of data about the negative global impact of the human economy on natural systems, is moving toward a world view that places consumption and production squarely in its behavioral and biophysical context. We argue that abandoning the straightjacket of the Walrasian core is essential to further progress in understanding the complex, coupled interactions between the human economy and the natural world. We call for a new framework for economic theory and policy that is consistent with observed human behavior, recognizes the complex and frequently irreversible interaction between human and natural systems, and directly confronts the cumulative negative effects of the human economy on the Earth's life support systems. Biophysical economics and ecological economics are two emerging economic frameworks in this movement.  相似文献   

17.
As drivers of terrestrial ecosystems, humans have replaced large carnivores in most areas, and human influence not only exerts striking ecological pressures on biodiversity at local scales but also has indirect effects in distant corners of the world. We suggest that the multibillion dollar cashmere industry creates economic motivations that link western fashion preferences for cashmere to land use in Central Asia. This penchant for stylish clothing, in turn, encourages herders to increase livestock production which affects persistence of over 6 endangered large mammals in these remote, arid ecosystems. We hypothesized that global trade in cashmere has strong negative effects on native large mammals of deserts and grassland where cashmere‐producing goats are raised. We used time series data, ecological snapshots of the biomass of native and domestic ungulates, and ecologically and behaviorally based fieldwork to test our hypothesis. In Mongolia increases in domestic goat production were associated with a 3‐fold increase in local profits for herders coexisting with endangered saiga (Saiga tatarica).That increasing domestic grazing pressure carries fitness consequences was inferred on the basis of an approximately 4‐fold difference in juvenile recruitment among blue sheep (Pseudois nayaur)in trans‐Himalayan India. Across 7 study areas in Mongolia, India, and China's Tibetan Plateau, native ungulate biomass is now <5% that of domestic species. Such trends suggest ecosystem degradation and decreased capacity for the persistence of native species, including at least 8 Asian endemic species: saiga, chiru (Pantholops hodgsoni), Bactrian camel (Camelus bactrianus), snow leopard(Panthera uncia), khulan(Equus hemionus), kiang (E. kiang), takhi (E. przewalski), and wild yak (Bos mutus). Our results suggest striking yet indirect and unintended actions that link trophic‐level effects to markets induced by the trade for cashmere. Globalización del Mercado de Cachemira y la Declinación de Mamíferos Mayores en Asia Central  相似文献   

18.
The high conservational value of the lichen-rich vegetation and landscape of the marine foreland Ørkenen on the isle of Anholt is treated from a Danish as well as a European perspective. The sensitivity of the lichen-rich vegetation to physical disturbance is emphasized. The impact of invasive species such asPinus mugo as well as the effect of atmospheric deposition of nutrients on the heaths at Anholt is described. Considerations related to the development of a management plan for Ørkenen are presented.  相似文献   

19.
Summary The attraction of Old World leaf beetles in the genusAulacophora to kairomones and parakairomones which are effective lures for New WorldDiabrotica andAcalymma were investigated. Beetles captured on sticky traps baited with single and multicomponent lures were no different from the control traps for two species ofAulacophora. Yellow colored traps and squash blossoms are attractive toAulacophora beetles which detect sub-microgram quantities of cucurbitacins on silica gel. Leaf feeding behavior and flight activity data are correlated with varietal preference of threeAulacophora species. The common response byDiabrotica andAulacophora to cucurbitacins reinforces the two groups' coevolutionary association with the Cucurbitaceae. The apparent lack of a common response toCucurbita blossom volatiles suggests recent evolutionary pathways are substantially different for these two groups of beetles.  相似文献   

20.
Assessing causes of population decline is critically important to management of threatened species. Stochastic patch occupancy models (SPOMs) are popular tools for examining spatial and temporal dynamics of populations when presence–absence data in multiple habitat patches are available. We developed a Bayesian Markov chain method that extends existing SPOMs by focusing on past environmental changes that may have altered occupancy patterns prior to the beginning of data collection. Using occupancy data from 3 creeks, we applied the method to assess 2 hypothesized causes of population decline—in situ die-off and residual impact of past source population loss—in the California red-legged frog. Despite having no data for the 20–30 years between the hypothetical event leading to population decline and the first data collected, we were able to discriminate among hypotheses, finding evidence that in situ die-off increased in 2 of the creeks. Although the creeks had comparable numbers of occupied segments, owing to different extinction–colonization dynamics, our model predicted an 8-fold difference in persistence probabilities of their populations to 2030. Adding a source population led to a greater predicted persistence probability than did decreasing the in situ die-off, emphasizing that reversing the deleterious impacts of a disturbance may not be the most efficient management strategy. We expect our method will be useful for studying dynamics and evaluating management strategies of many species.  相似文献   

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