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1.
Ecologically relevant traits of organisms in an assemblage determine an ecosystem's functional fingerprint (i.e., the shape, size, and position of multidimensional trait space). Quantifying changes in functional fingerprints can therefore provide information about the effects of diversity loss or gain through time on ecosystem condition and is a promising approach to monitoring ecological integrity. This, however, is seldom possible owing to limitations in historical surveys and a lack of data on organismal traits, particularly in diverse tropical regions. Using data from detailed bird surveys from 4 periods across more than a century, and morphological and ecological traits of 233 species, we quantified changes in the avian functional fingerprint of a tropical montane forest in the Andes of Colombia. We found that 78% of the variation in functional space, regardless of period, was described by 3 major axes summarizing body size, dispersal ability (indexed by wing shape), and habitat breadth. Changes in species composition significantly altered the functional fingerprint of the assemblage and functional richness and dispersion decreased 35–60%. Owing to species extirpations and to novel additions to the assemblage, functional space decreased over time, but at least 11% of its volume in the 2010s extended to areas of functional space that were unoccupied in the 1910s. The assemblage now includes fewer large-sized species, more species with greater dispersal ability, and fewer habitat specialists. Extirpated species had high functional uniqueness and distinctiveness, resulting in large reductions in functional richness and dispersion after their loss, which implies important consequences for ecosystem integrity. Conservation efforts aimed at maintaining ecosystem function must move beyond seeking to sustain species numbers to designing complementary strategies for the maintenance of ecological function by identifying and conserving species with traits conferring high vulnerability such as large body size, poor dispersal ability, and greater habitat specialization. Article impact statement: Changes in functional fingerprints provide a means to quantify the integrity of ecological assemblages affected by diversity loss or gain.  相似文献   
2.
Maintenance of biodiversity through seed banks and botanical gardens, where the wealth of species’ genetic variation may be preserved ex situ, is a major goal of conservation. However, challenges can persist in optimizing ex situ collections if trade-offs exist among cost, effort, and conserving species evolutionary potential, particularly when genetic data are not available. We evaluated the genetic consequences of population preservation informed by geographic (isolation by distance [IBD]) and environmental (isolation by environment [IBE]) distance for ex situ collections for which population provenance is available. We used 19 genetic and genomic data sets from 15 plant species to assess the proportion of population genetic differentiation explained by geographic and environmental factors and to simulate ex situ collections prioritizing source populations based on pairwise geographic distance, environmental distance, or both. Specifically, we tested the impact prioritizing sampling based on these distances may have on the capture of neutral, functional, or putatively adaptive genetic diversity and differentiation. Individually, IBD and IBE explained limited population genetic differences across all 3 genetic marker classes (IBD, 10–16%; IBE, 1–5.5%). Together, they explained a substantial proportion of population genetic differences for functional (45%) and adaptive (71%) variation. Simulated ex situ collections revealed that inclusion of IBD, IBE, or both increased allelic diversity and genetic differentiation captured among populations, particularly for loci that may be important for adaptation. Thus, prioritizing population collections based on environmental and geographic distance data can optimize genetic variation captured ex situ. For the vast majority of plant species for which there is no genetic information, these data are invaluable to conservation because they can guide preservation of genetic variation needed to maintain evolutionary potential within collections.  相似文献   
3.
为有效克服FRAM事故分析中无法进行定量分析的缺陷,提出结合模糊推理技术的Fuzzy FRAM模型。此改进模型基于FRAM识别系统运行状态;依据功能输出要素的时间/精度属性利用Matlab构建2阶模糊推理系统量化功能输出质量;根据通用性能条件(CPC)及功能输入耦合端口构建功能评价体系,针对评价体系中存在的不确定性信息融合及建模问题,采用模糊证据推理技术,通过模糊信度结构建立、数据处理、信息融合测度后获得功能的风险指数;以既有铁路危险品运输事故为例,验证方法的可行性。结果表明:Fuzzy FRAM模型的评估结果较为精确,是FRAM分析方法的有效补充。  相似文献   
4.
Scientific insights into what it means to manage on-farm trees by local farmers, is an essential step towards documenting local ecological knowledge for sustainable landscape management. A study was therefore conducted in the Kumawu Forest District in the Ashanti Region of Ghana to assess how farmers conceptualise on-farm tree management and develop local knowledge for it. Using a case study approach, data were collected through informal interviews and focus group discussions with 120 farmers drawn from 15 communities who were involved in the management of three cropping systems; cocoa, maize and cassava-cocoyam-plantain mix. It was observed that the farmers regard on-farm tree management as a continuous process which occurs in three phases of the farming cycle; land preparation, crop cultivation and fallow management. For each of the three phases, farmers are guided by specific principles that ensure enough light penetration in-between tree crowns in the land preparation phase, suitable spacing between trees and crops in the crop cultivation phase and adequate tree regeneration in the fallow phase. The decisions made during the selection of tree species, spacing of trees adjudged suitable for any particular cropping system and recruitment of saplings prior to the fallow phase of farming constitute tree management. Farmers develop tree management knowledge by studying the physical characteristics of species, matching them to ecological functions they could perform and how they are likely to respond to treatments meant to control or enhance their development. Species are then subjected to trial and recommended or otherwise.  相似文献   
5.
贵阳市不同粒级地表灰尘中As、Ni水平及权重   总被引:1,自引:0,他引:1  
根据贵阳市城区土地利用的情况,在不同功能区地表采集灰尘样品,分析As、Ni含量及变异规律。结果表明:贵阳市地表灰尘As、Ni含量分别为17.4mg/kg和50.0mg/kg。工业区地表灰尘中As、Ni含量最高,商贸区和校园等区域As、Ni水平较低。贵阳市地表灰尘中不同颗粒物的质量百分比大小为细颗粒(<105μm)>中等颗粒(105~250μm)>粗颗粒(250~425μm)。As在不同粒径灰尘中含量差别不大,Ni在不同粒径灰尘中含量随粒径增加而降低。细颗粒对灰尘As、Ni的贡献分别为42%和47%。除垃圾站外,贵阳市各功能区地表灰尘不同粒径颗粒物百分比随粒径增大而减小,其中交通区地表灰尘细颗粒所占比例最大。垃圾站地表灰尘中不同粒径颗粒百分比则随粒径增大而增大,As、Ni在垃圾站地表灰尘中颗粒物贡献为中等颗粒>粗颗粒>细颗粒,其余功能区不同粒径颗粒物的贡献基本为细颗粒大于粗颗粒。  相似文献   
6.
噪声功能区划分是环境保护工作的主要内容之一。通过对营口市老边区自然条件及城区状况的分析,对噪声区域进行了详细科学的划分,为提高人居环境质量、加强噪声防治工作及城市规划建设提供了参考。  相似文献   
7.
按照《大理州地表水水环境功能区划技术方案》对大理市地表水水环境功能进行了区划,划分了不同类型的水功能区,用来指导、约束水资源开发利用和保护的实践活动,可作为水资源管理的依据。  相似文献   
8.
水库的出流是影响水库流场的重要因素,也是影响水库水环境容量的重要因素。文章以某水库为例,利用计算流体力学及水质计算软件计算了水库在不同泄流宽度下出流的流量,并根据不同泄流宽度下水库的流场和浓度场计算了对应的水库环境容量值,分析了出流宽度、出流流量和水环境容量三者之间的关系。  相似文献   
9.
运用层次分析法对功能区噪声进行优选,各功能区噪声监测点位个数分配根据功能区面积和复杂性、各功能区噪声监测点位确定根据专家比例标度赋值进行评定。  相似文献   
10.
Degradation of chlorpyrifos at different concentrations in soil and its impact on soil microbial functional diversity were investigated under laboratory conditions. The degradation half-lives of chlorpyrifos at levels of 4, 8, and 12 mg/kg in soil were calculated to be 14.3, 16.7, and 18.0 d, respectively. The Biolog study showed that average well color development (AWCD) in soils was significantly (P < 0.05) inhibited by chlorpyrifos within the first two weeks and thereafter recovered to the similar level as the control. A similar variation in the diversity indices (Simpson index 1/D and McIntosh index U) in chlorpyrifos-treated soils was observed, no significant difference in the Shannon-Wiener index H' was found in these soils. With increasing chlorpyrifos concentration, the half-lives of chlorpyrifos were significantly (P ≤ 0.05) extended and its inhibitory effects on soil microorganisms were aggravated. It is concluded that chlorpyrifos residues in soil had a temporary or short-term inhibitory effect on soil microbial functional diversity.  相似文献   
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