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1.
Wildlife diseases pose an increasing threat to biodiversity and are a major management challenge. A striking example of this threat is the emergence of chytridiomycosis. Despite diagnosis of chytridiomycosis as an important driver of global amphibian declines 15 years ago, researchers have yet to devise effective large‐scale management responses other than biosecurity measures to mitigate disease spread and the establishment of disease‐free captive assurance colonies prior to or during disease outbreaks. We examined the development of management actions that can be implemented after an epidemic in surviving populations. We developed a conceptual framework with clear interventions to guide experimental management and applied research so that further extinctions of amphibian species threatened by chytridiomycosis might be prevented. Within our framework, there are 2 management approaches: reducing Batrachochytrium dendrobatidis (the fungus that causes chytridiomycosis) in the environment or on amphibians and increasing the capacity of populations to persist despite increased mortality from disease. The latter approach emphasizes that mitigation does not necessarily need to focus on reducing disease‐associated mortality. We propose promising management actions that can be implemented and tested based on current knowledge and that include habitat manipulation, antifungal treatments, animal translocation, bioaugmentation, head starting, and selection for resistance. Case studies where these strategies are being implemented will demonstrate their potential to save critically endangered species. Intervenciones para Reducir el Riesgo de Extinción en Anfibios Amenazados por la Quitridiomicosis  相似文献   
2.
内分泌干扰物作为一类新型污染物,由于其在环境水体中微量的浓度即可对野生动物产生内分泌干扰效应,因此引起了人们的广泛关注.本文以两类主要内分泌干扰物(即类固醇雌激素和酚类内分泌干扰物)作为研究对象,综述了它们在城市污水处理厂中的浓度水平以及相应的去除效率,并探讨了不同生物处理工艺、运行操作条件等对去除效率的影响.此外,通...  相似文献   
3.
Establishing IUCN Red List Criteria for Threatened Ecosystems   总被引:1,自引:0,他引:1  
Abstract: The potential for conservation of individual species has been greatly advanced by the International Union for Conservation of Nature's (IUCN) development of objective, repeatable, and transparent criteria for assessing extinction risk that explicitly separate risk assessment from priority setting. At the IV World Conservation Congress in 2008, the process began to develop and implement comparable global standards for ecosystems. A working group established by the IUCN has begun formulating a system of quantitative categories and criteria, analogous to those used for species, for assigning levels of threat to ecosystems at local, regional, and global levels. A final system will require definitions of ecosystems; quantification of ecosystem status; identification of the stages of degradation and loss of ecosystems; proxy measures of risk (criteria); classification thresholds for these criteria; and standardized methods for performing assessments. The system will need to reflect the degree and rate of change in an ecosystem's extent, composition, structure, and function, and have its conceptual roots in ecological theory and empirical research. On the basis of these requirements and the hypothesis that ecosystem risk is a function of the risk of its component species, we propose a set of four criteria: recent declines in distribution or ecological function, historical total loss in distribution or ecological function, small distribution combined with decline, or very small distribution. Most work has focused on terrestrial ecosystems, but comparable thresholds and criteria for freshwater and marine ecosystems are also needed. These are the first steps in an international consultation process that will lead to a unified proposal to be presented at the next World Conservation Congress in 2012.  相似文献   
4.
以硝基苯、苯胺为主要污染物的污染地下水为研究对象,加入激活剂(乳糖、Na2HPO4、乳糖+Na2HPO4、乙醇、牛肉膏、蛋白胨)激活土著微生物,并考察其对土著微生物生长及硝基苯、苯胺降解效果的影响。加入激活剂3d后测各个水样的脱氢酶活性,对培养9d后的水样进行气相色谱/质谱(GC/MS)分析。结果表明,加入乳糖的水样中,其微生物相对增长率达157.2%,硝基苯、苯胺的相对去除率分别为14.90%和0.79%;加入Na2HPO4和乙醇的水样中,其微生物增长和硝基苯、苯胺降解情况均没有明显变化;加入乳糖+Na2HPO4的水样中,微生物相对增长率达180.3%,硝基苯、苯胺的相对去除率分别为24.20%和1.21%;加入牛肉膏的水样中,微生物的相对增长率为830.7%,硝基苯、苯胺的相对去除率分别为99.99%和99.67%;加入蛋白胨的水样中,其微生物相对增长率为686.0%,硝基苯、苯胺的相对去除率分别为99.33%和58.94%。GC/MS分析结果表明,加入激活剂后对氯苯胺、1-甲基-4-硝基苯等其他有机物的降解率均有提高。由此可见,通过激活土著微生物修复有机物污染地下水是可行的。  相似文献   
5.
Abstract: The growing demand for biofuels is promoting the expansion of a number of agricultural commodities, including oil palm (Elaeis guineensis). Oil‐palm plantations cover over 13 million ha, primarily in Southeast Asia, where they have directly or indirectly replaced tropical rainforest. We explored the impact of the spread of oil‐palm plantations on greenhouse gas emission and biodiversity. We assessed changes in carbon stocks with changing land use and compared this with the amount of fossil‐fuel carbon emission avoided through its replacement by biofuel carbon. We estimated it would take between 75 and 93 years for the carbon emissions saved through use of biofuel to compensate for the carbon lost through forest conversion, depending on how the forest was cleared. If the original habitat was peatland, carbon balance would take more than 600 years. Conversely, planting oil palms on degraded grassland would lead to a net removal of carbon within 10 years. These estimates have associated uncertainty, but their magnitude and relative proportions seem credible. We carried out a meta‐analysis of published faunal studies that compared forest with oil palm. We found that plantations supported species‐poor communities containing few forest species. Because no published data on flora were available, we present results from our sampling of plants in oil palm and forest plots in Indonesia. Although the species richness of pteridophytes was higher in plantations, they held few forest species. Trees, lianas, epiphytic orchids, and indigenous palms were wholly absent from oil‐palm plantations. The majority of individual plants and animals in oil‐palm plantations belonged to a small number of generalist species of low conservation concern. As countries strive to meet obligations to reduce carbon emissions under one international agreement (Kyoto Protocol), they may not only fail to meet their obligations under another (Convention on Biological Diversity) but may actually hasten global climate change. Reducing deforestation is likely to represent a more effective climate‐change mitigation strategy than converting forest for biofuel production, and it may help nations meet their international commitments to reduce biodiversity loss.  相似文献   
6.
营养盐水平对念珠藻胞外有机物产生的影响   总被引:2,自引:1,他引:1       下载免费PDF全文
齐飞  刘晓媛  徐冰冰  贲岳  封莉  张立秋 《环境科学》2012,33(5):1556-1563
以我国湖泊典型固氮蓝藻发状念珠藻(Nostoc flagelliforme)为研究对象,考察了氮、磷营养盐对发状念珠藻生长特性及其胞外有机物产生的影响.采用藻细胞浓度计数法表征发状念珠藻生长特性;分别采用溶解性有机碳(DOC)、三维荧光光谱(EEM)和紫外-可见光谱法,从总量和主要物质方面分析了发状念珠藻胞外有机物的产生规律.结果表明,在不同氮、磷营养水平下,发状念珠藻的4个关键生长时期基本相同,氮是控制发状念珠藻生长的关键营养控制要素;氮营养元素浓度的增高,有利于发状念珠藻产生胞外有机物,其产生量逐渐增大,而磷营养元素浓度的增高对胞外有机物产生量贡献较小,氮营养盐是发状念珠藻产生胞外有机物的关键限制因子;通过EEM谱图分析,发状念珠藻胞外有机物主要以类氨基酸类物质和类富里酸物质为主.以磷为控制营养盐时,类富里酸是主要的胞外有机物之一,以氮为控制营养盐时,类富里酸产生量极低;作为主要的胞外有机物,蛋白质和碳水化合物的产生规律显著不同,其中蛋白质含量显著高于碳水化合物含量.  相似文献   
7.
目前计算结构滞回阻尼比常用的方法是能量比法,该方法在给定滞回模型的基础上采用滞回耗能与结构总弹性应变能的比值求得结构滞回阻尼比,但该方法是建立在简谐激励下结构稳态响应的基础之上,对于真实地震下结构滞回阻尼比计算并不完全适用。考虑到这一不足,本文提出一种新的迭代计算结构滞回阻尼比的方法,在Carlos提出的结构滞回阻尼比计算方法的基础上,考虑地震激励频率对阻尼比的影响,通过改进Carlos迭代计算方法,得到了考虑地震激励频率影响的滞回阻尼比计算公式,通过该公式分析得出了不同延性系数和周期比对滞回阻尼比的影响规律,结果表明不同延性系数的结构滞回阻尼比会随着周期比的增大先增大再减小。本研究可为结构进入非线性状态后减震结构总体阻尼比的计算提供理论依据。  相似文献   
8.
以呋喃丹、对硝基苯氯甲酸酯和6-氨基己酸合成呋喃丹半抗原: 6-[[ (2,3-二氢-2,2-二甲基-7-苯并呋喃基氧)羰基]氨基]己酸(BFNH).将半抗原与载体蛋白(BSA,OVA)偶联制备呋喃丹人工免疫抗原和包被抗原.利用BFNH-BSA免疫家兔获得抗呋喃丹的多克隆抗体, 并通过间接ELISA法测定抗体的效价. 结果表明,家兔抗血清效价达1.28×106. 采用正辛酸-硫酸铵二步沉淀法纯化抗体, 纯化后抗体效价达到1.024×107, 经10% SDS-PAGE分析, 重、轻链分子量分别约为55 kD和22 kD.  相似文献   
9.
建立了一套中试规模的污泥臭氧原位减量(SOR)系统,通过长期(111 d)运行考察了其对四环素、土霉素、强力霉素和阿奇霉素的去除效果.结果表明,SOR工艺可以实现剩余污泥零排放,化学需氧量和氮的去除性能与常规厌氧/缺氧/好氧(A/A/O)工艺接近,但除磷性能有所下降.SOR工艺出水中目标抗生素浓度与常规A/A/O工艺无明显差别,而污泥中目标抗生素含量明显低于常规A/A/O工艺.质量衡算表明,目标抗生素在A/A/O及SOR工艺中的输入输出均渐趋平衡;SOR工艺进水中91.2%~98.1%的目标抗生素被臭氧降解,而常规A/A/O工艺进水中82.3%~91.2%的目标抗生素随剩余污泥排放.因此,SOR工艺可以同步削减污水处理厂中剩余污泥及抗生素向环境中的排放.  相似文献   
10.
Abstract:  Birds are frequently used as indicators of ecosystem health and are the most comprehensively studied class in the animal kingdom. Nevertheless, a comprehensive, interspecific assessment of the correlates of avian genetic diversity is lacking, even though indices of genetic diversity are of considerable interest in the conservation of threatened species. We used published data on variation at microsatellite loci from 194 bird species to examine correlates of diversity, particularly with respect to conservation status and population size. We found a significant decline in mean heterozygosity with increasing extinction risk, and showed, by excluding species whose heterozygosity values were calculated with heterospecific primers, that this relationship was not dependent on ascertainment bias. Results of subsequent regression analyses suggested that smaller population sizes of threatened species were largely responsible for this relationship. Thus, bird species at risk of extinction are relatively depauperate in terms of neutral genetic diversity, which is expected to make population recovery more difficult if it reflects adaptive genetic variation. Conservation policy will need to minimize further loss of diversity if the chances of saving threatened species are to be maximized.  相似文献   
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