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1.
衡先培  王志芳  戴芹芹  姜芊孜 《生态学报》2016,36(13):4152-4162
景观安全格局作为一种生态规划途径,其识别过程具有综合性和复杂性。立足于水安全格局,力求挖掘地方知识在解决特定场地水生态问题中的意义。研究区域为重庆御临河流域的石船、龙兴镇。"谷歌地图+辅助问卷"的方法收集了大量地方知识对场地水过程的认知(包括雨洪、灌溉过程,饮用水过程,捕鱼过程等)。研究对比了地方知识与科学知识的关系,通过结合两者的信息共同构建当地的水安全格局,并在过程中总结了地方知识在水安全格局识别中的作用。研究肯定了地方知识在水安全格局识别过程中的重要价值。地方知识与科学知识在一些水过程识别结果上具有很强的相似性。在科学数据充分的情况下,地方知识是对科学识别的有效补充及模型校正,例如能够为径流和径流交汇点等级划分提供地方依据。在科学数据匮乏的情况下,地方知识能够快速支撑某些水过程的分析以及格局识别,例如地方知识能够识别出地下水水位、地下河、鱼类栖息地与产卵场等关键空间要素,并且提供微观的调节措施以减少水库运行对鱼类的影响。整体而言,地方知识具有一定独立识别大尺度雨洪安全格局的能力,但也有自身的局限,包括认知范围狭小,地方性强等。研究为地方知识在景观安全格局应用中的科学体系提供了一个初步探索。  相似文献   

2.
Local communities have preferences and expectations regarding mangrove ecosystems that are typically underrepresented in valuation studies. Therefore, this study identifies how the local community of Mahahual (Mexico) perceives the ecosystem services provided by the mangrove forest and how these preferences differ between households. A survey was designed by one of the authors and local stakeholders building on previous knowledge and experts (local environmental research centre and non-governmental organisation Takata and its experts in biology and coastal conservation, ecotourism businesses’ owners, and the mayor of the village). The survey is used to cover a wide range of ecosystem services such as carbon sequestration, recreation and cultural activities as well as improved connectivity with local seagrass beds and coral reefs. Ecosystem services were specifically chosen by biologists and ecologists of the local NGO to perfectly reflect the local mangroves ecosystem. The small land area of the village, its low population and its rapid expansion offer a unique context, aiming at preserving the natural environment while keeping in mind that the main economy is based on tourism. While mangroves are greatly appreciated for the local protective services they provide such as coastal protection, local inhabitants also care about services that have a wider impact such as biodiversity and carbon sequestration. We find that the educational background of local inhabitants plays an important role in determining the importance of local ecosystem services and that information provision can help to counterbalance this effect. We also observe that preferences for specific ecosystem services differ based on how close residents live to the mangroves and to the coast, which accentuates the different needs and ideas of the households based on their local neighbourhood.  相似文献   

3.
Richard Jenkins 《Ethnos》2013,78(3):367-389
How can ethnographers see the ‘big picture’, while they are busy with everyday minutiae? Awareness of the local impacts of history and globalisation has revived debates about the pragmatics of fieldwork. Arguing that most fieldwork remains, for most practitioners, ‘local’, this paper explores how it is possible to apprehend change ethnographically. Something of how local people understand and experience change, as it happens to them and around them and as they contribute to it, can be grasped in ‘significant local imagery’, in this case, ‘significant people’, ‘significant things’, and ‘significant events’. These images are recognised in local discourse as indicative or ‘telling’ of change, and can be used to summarise analytically, and shed light on, wider vistas of change. This paper presents three local images deriving from fieldwork in a small town in mid-Jutland and uses them to tell a bigger story, a narrative about the modernisation of Danish society.  相似文献   

4.
* Local adaptation is common, but tests for adaptive differentiation frequently compare populations from strongly divergent environments, making it unlikely that any influence of stochastic processes such as drift or mutation on local adaptation will be detected. Here, the hypothesis that local adaptation is more likely to develop when the native environments of populations are more distinct than when they are similar was tested. * A reciprocal transplant experiment including two populations from each of three habitats was conducted to determine the pattern of local adaptation. In addition to testing for local adaptation at the population level, the hypothesis was tested that local adaptation is more common between populations from different habitats than between populations from the same habitat. * Local adaptation was not common, but more evidence was found of local adaptation between populations from different habitats than between populations from the same habitat. Two instances of foreign genotype fitness advantage confirm that stochastic processes such as drift can limit local adaptation. * These results are consistent with the hypothesis that stochastic processes can inhibit local adaptation but are more likely to be overwhelmed by natural selection when populations occur in divergent environments.  相似文献   

5.
Populations that are structured into small local patches are a common feature of ecological and epidemiological systems. Models describing this structure are often referred to as metapopulation models in ecology or household models in epidemiology. Small local populations are subject to demographic stochasticity. Theoretical studies of household disease models without resistant stages (SIS models) have shown that local stochasticity can be ignored for between patch disease transmission if the number of connected patches is large. In that case the distribution of the number of infected individuals per household reaches a stationary distribution described by a birth-death process with a constant immigration term. Here we show how this result, in conjunction with the balancing condition for birth-death processes, provides a framework to estimate demographic parameters from a frequency distribution of local population sizes. The parameter estimation framework is applicable to estimate parameters of disease transmission models as well as metapopulation models.  相似文献   

6.
Weak trophic interactions have been shown to promote the stability of ecological food webs characterized by perfect mixing. However, their importance at the landscape level and response to enrichment has not been extensively examined. In this paper we examine the food-web model explored by McCann et al. [1998. Weak trophic interactions and the balance of nature. Nature 395, 794-798]. The model is expanded into a metacommunity construct where local communities are coupled through global or local dispersal. We analyze global and local stability, as well as spatial synchrony in relation to trophic interaction strength and dispersal regimes. Results reveal that weak interactions can operate through two scale-dependent mechanisms: (i) under low local dispersal regimes, local stabilization of each community under weak interactions directly scales-up to global stability. (ii) Under high local dispersal, asynchronous local destabilization associated with weak interactions proves the driver behind global stability. In the face of enrichment, weak trophic interactions are shown to be instrumental in promoting global stability when dispersal is local. These results demonstrate how the importance of weak trophic interactions can be generalized at the landscape level despite contrary local predictions.  相似文献   

7.
Transnational Human Rights and Local Activism: Mapping the Middle   总被引:2,自引:0,他引:2  
How do transnational ideas such as human rights approaches to violence against women become meaningful in local social settings? How do they move across the gap between a cosmopolitan awareness of human rights and local sociocultural understandings of gender and family? Intermediaries such as community leaders, nongovernmental organization participants, and social movement activists play a critical role in translating ideas from the global arena down and from local arenas up. These are people who understand both the worlds of transnational human rights and local cultural practices and who can look both ways. They are powerful in that they serve as knowledge brokers between culturally distinct social worlds, but they are also vulnerable to manipulation and subversion by states and communities. In this article, I theorize the process of translation and argue that anthropological analysis of translators helps to explain how human rights ideas and interventions circulate around the world and transform social life.  相似文献   

8.
1. A critical need in conservation biology is to determine which species are most vulnerable to extinction. Freshwater mussels (Bivalvia: Unionacea) are one of the most imperilled faunal groups globally. Freshwater mussel larvae are ectoparasites on fish and depend on the movement of their hosts to maintain connectivity among local populations in a metapopulation. 2. I calculated local colonisation and extinction rates for 16 mussel species from 14 local populations in the Red River drainage of Oklahoma and Texas, U.S. I used general linear models and AIC comparisons to determine which mussel life history traits best predicted local colonisation and extinction rates. 3. Traits related to larval dispersal ability (host infection mode, whether a mussel species was a host generalist or specialist) were the best predictors of local colonisation. 4. Traits related to local population size (regional abundance, time spent brooding) were the best predictors of local extinction. The group of fish species used as hosts by mussels also predicted local extinction and was probably related to habitat fragmentation and host dispersal abilities. 5. Overall, local extinction rates exceeded local colonisation rates, indicating that local populations are becoming increasingly isolated and suffering an ‘extinction debt’. This study demonstrates that analysis of species traits can be used to predict local colonisation and extinction patterns and provide insight into the long‐term persistence of populations.  相似文献   

9.
Li Q  Zhou C  Liu H 《Proteins》2009,74(4):820-836
General and transferable statistical potentials to quantify the compatibility between local structures and local sequences of peptide fragments in proteins were derived. In the derivation, structure clusters of fragments are obtained by clustering five-residue fragments in native proteins based on their conformations represented by a local structure alphabet (de Brevern et al., Proteins 2000;41:271-287), secondary structure states, and solvent accessibilities. On the basis of the native sequences of the structurally clustered fragments, the probabilities of different amino acid sequences were estimated for each structure cluster. From the sequence probabilities, statistical energies as a function of sequence for a given structure were directly derived. The same sequence probabilities were employed in a database-matching approach to derive statistical energies as a function of local structure for a given sequence. Compared with prior models of local statistical potentials, we provided an integrated approach in which local conformations and local environments are treated jointly, structures are treated in units of fragments instead of individual residues so that coupling between the conformations of adjacent residues is included, and strong interdependences between the conformations of overlapping or neighboring fragment units are also considered. In tests including fragment threading, pseudosequence design, and local structure predictions, the potentials performed at least comparably and, in most cases, better than a number of existing models applicable to the same contexts indicating the advantages of such an integrated approach for deriving local potentials and suggesting applicability of the statistical potentials derived here in sequence designs and structure predictions.  相似文献   

10.
The fluorescent probe 1-anilinonaphthalene 8-sulfonate was used to examine the binding of spin-labeled local anesthetics to lipid model systems, to the membranes of human red blood cells, and rabbit sarcoplasmic reticulum. 1-Anilinonaphthalene 8-sulfonate exhibits two distinct fluorescent lifetimes when bound to these biological membranes. The shorter lifetime represents the probe associated with the purely lipid region while the longer lifetime is associated with the protein region. The spin-labeled local anesthetic quenches the fluorescence of both of these components as indicated by the decrease in the lifetimes. Since nitroxide free radicals are known to quench fluorophores upon 'contract', the results reflect the relative interaction of local anesthetics with membrane lipids and proteins. The evidence is consistent with the concept of multiple binding sites for local anesthetics in membranes. Local anesthetics, once intercalated into the bilayer, may diffuse laterally and interact with membrane components, lipid as well as proteins. In biological membranes, however, positively charged local anesthetics are better able to quench 1-anilinonaphthalene 8-sulfonate in protein regions, suggesting that the interaction between local anesthetics and membrane proteins can be electrostatic in nature.  相似文献   

11.
Mathematical models can help to resolve the longstanding question of whether more diverse communities are more stable. Here, I focus on how local dispersal and local interactions--hallmarks of spatial communities--affect stability in a spatially implicit model with demographic stochasticity. The results are based on a novel way to analyze moment equations. The main conclusion is that the type and strength of density-dependent factors, such as fecundity and competition, determine whether local dispersal and local interactions increase or decrease stability. Local dispersal has a stabilizing effect when fecundity is high, interspecific competition is either low or high, and the number of species is small. Effects of local migration on stability are amplified when space is explicit.  相似文献   

12.
The oral surgical anaesthesia is field in which usually long-acting local anaesthetics are being used. Some of the currently used acting local anaesthetics as Levobupivacaine or Ropivacaine have reduced cardiac toxicity. The aim of this review is to provide an overview of acting mechanisms when anaesthetic agents are applied in oral surgery and the effect that they may have in patients with chronic concurrent cardiac conditions. There are notable linking the property of the local anaesthetics lipid solubility and the potency of local anaesthetic-induced vasoconstriction which can additionally compromise cardiac function in patients with previously impaired cardiac function.  相似文献   

13.
Monitoring Matters: Examining the Potential of Locally-based Approaches   总被引:8,自引:7,他引:1  
Monitoring of biodiversity and resource use by professional scientists is often costly and hard to sustain, especially in developing countries, where financial resources are limited. Moreover, such monitoring can be logistically and technically difficult and is often perceived to be irrelevant by resource managers and the local communities. Alternatives are emerging, carried out at a local scale and by individuals with little formal education. The methods adopted span a spectrum, from participatory monitoring where aims and objectives are defined by the community, to ranger-based monitoring in protected areas. What distinguishes these approaches is that local people or local government staff are directly involved in data collection and (in most instances) analysis. In this issue of Biodiversity and Conservation, 15 case studies examine whether these new approaches can address the limitations of professional monitoring in developing countries. The case studies evaluate ongoing locally-based monitoring schemes involving more than 1500 community members in 13 countries. The papers are based on a symposium held in Denmark in April 2004 (www. monitoringmatters.org). Here, we review how the case studies shed light on the following key issues concerning locally-based methods: cost, sustainability, their ability to detect true local or larger-scale trends, their links to management decisions and action, and the empowerment of local constituencies. Locally-based monitoring appears to be consistently cheap relative to the costs of management and of professional monitoring, even though the start-up costs can be high. Most local monitoring schemes are still young and thus their chances of being sustained over the longer term are not yet certain. However, we believe their chances of surviving are better than many professional schemes, particularly when they are institutionalised within existing management structures, and linked to the delivery of ecosystem goods or services to local communities. When properly designed, local schemes yield locally relevant results that can be as reliable as those derived from professional monitoring. Many management decisions emanate from local schemes. The decisions appear to be taken promptly, in response to immediate threats to the environment, and often lead to community-based actions to protect habitats, species or the local flow of ecosystem benefits; however, few local schemes have so far led to actions beyond the local scale. Locally-based monitoring schemes often reinforce existing community-based resource management systems and lead to change in the attitude of locals towards more environmentally sustainable resource management. Locally-derived data have considerable unexplored potential to elucidate global patterns of change in the status of populations and habitats, the services they provide, and the threats they face, but more effort is needed to develop effective modalities for feeding locally-derived data up to national and international levels.  相似文献   

14.
Aims (1) To determine the relationship between local and regional anthropoid primate species richness. (2) To establish the spatial and temporal scale at which the ultimate processes influencing patterns of primate species coexistence operate. Location Continental landmasses of Africa, South America and Asia (India to China, and all islands as far south as New Guinea). Methods The local–regional species richness relationship for anthropoid primates is estimated by regressing local richness against regional richness (independent variable). Local richness is estimated in small, replicate local assemblages sampled in regions that vary in total species richness. A strong linear relationship is taken as evidence that local assemblages are unsaturated and local richness results from proportional sampling of the regional pool. An asymptotic curvilinear relationship is interpreted to reflect saturated communities, where strong biotic interactions limit local richness and local processes structure the species assemblage. As a further test of the assumption of local assemblage saturation, we looked for density compensation in high‐density local primate assemblages. Results The local–regional species richness relationship was linear for Africa and South America, and the slope of the relationship did not differ between the two continents. For Asia, curvilinearity best described the relationship between local and regional richness. Asian primate assemblages appear to be saturated and this is confirmed by density compensation among Asian primates. However, density compensation was also observed among African primates. The apparent assemblage saturation in Asia is not a species–area phenomenon related to the small size of the isolated islands and their forest blocks, since similar low local species richness occurs in large forests on mainland and/or peninsular Asia. Main conclusions In Africa and South America local primate assemblage composition appears to reflect the influence of biogeographic processes operating on regional spatial scales and historical time scales. In Asia the composition of primate assemblages are by‐and‐large subject to ecological constraint operating over a relatively small spatial and temporal scale. The possible local influence of the El Niño Southern Oscillations on the evolution and selection of life‐history characteristics among Asian primates, and in determining local patterns of primate species coexistence, warrants closer inspection.  相似文献   

15.
突变热点区域是基因突变相对集中的区域,在生物的遗传和变异中有特殊的地位.针对特殊条件下发生突变形成的突变热点区域进行了相关研究.而人类基因组序列的测定和人类基因框架图的绘制,为在全基因组范围内进行突变热点研究提供了条件.分析了人类基因组中2 831个基因突变热点区域上简并度的性质,对突变热点区集中在高简并度区或者低简并度区的基因生物学功能进行了分析和分类.研究的焦点集中在某类功能的基因简并度特性一致的情况上.对搜集到的基因简并度特性利用聚类计算进行分析,找到了一些特殊的功能类,属于其中某类功能的基因能够通过聚类分析聚合到一起,从而说明简并度特性也是相近的,这为从基因的简并度特性预测表达物的功能提供了线索.  相似文献   

16.
Community detection has drawn a lot of attention as it can provide invaluable help in understanding the function and visualizing the structure of networks. Since single objective optimization methods have intrinsic drawbacks to identifying multiple significant community structures, some methods formulate the community detection as multi-objective problems and adopt population-based evolutionary algorithms to obtain multiple community structures. Evolutionary algorithms have strong global search ability, but have difficulty in locating local optima efficiently. In this study, in order to identify multiple significant community structures more effectively, a multi-objective memetic algorithm for community detection is proposed by combining multi-objective evolutionary algorithm with a local search procedure. The local search procedure is designed by addressing three issues. Firstly, nondominated solutions generated by evolutionary operations and solutions in dominant population are set as initial individuals for local search procedure. Then, a new direction vector named as pseudonormal vector is proposed to integrate two objective functions together to form a fitness function. Finally, a network specific local search strategy based on label propagation rule is expanded to search the local optimal solutions efficiently. The extensive experiments on both artificial and real-world networks evaluate the proposed method from three aspects. Firstly, experiments on influence of local search procedure demonstrate that the local search procedure can speed up the convergence to better partitions and make the algorithm more stable. Secondly, comparisons with a set of classic community detection methods illustrate the proposed method can find single partitions effectively. Finally, the method is applied to identify hierarchical structures of networks which are beneficial for analyzing networks in multi-resolution levels.  相似文献   

17.
Nobuhiro G   Haruo Abe 《Biopolymers》1981,20(5):991-1011
A statistical-mechanical model (a noninteracting local structure model) of folding and unfolding transition in globular proteins is described and a formulation is given to calculate the partition function. The process of transition is discussed in this model within the framework of equilibrium statistical mechanics. In order to clarify the range of applicability of such an approach, the characteristics of the folding and unfolding transition in globular proteins are analyzed from the statistical-physical point of view. A theoretical advantage is pointed out in studying folding and unfolding processes taking place as conformational fluctuations in individual protein molecules under macroscopic equilibrium at the melting temperature. In this case, paths of folding and unfolding are shown to be identical in the statistical sense. A key to the noninteracting local structure model lies in the concept of local structures and the assumption of the absence of interactions between local structures. A local structure is defined as a continuous section of the chain which takes the same or similar local conformation as in the native conformation. The assumption of the absence of inter-actions between local structures endows the model with the remarkable character that its partition function can be calculated exactly; thereby the equilibrium population of various conformations along the folding and unfolding paths can be discussed only by a knowledge of the folded native conformation.  相似文献   

18.
The adaptive potential of restored communities is important to their long‐term sustainability, particularly in the face of changing environmental conditions such as climate change. The genetic diversity of rainforest plants in restoration projects and their suitability to current and future environmental site conditions are important considerations for restoration practitioners and seed suppliers. Presented here are the results from a survey of rainforest restoration practitioners in North East New South Wales and South East Queensland, Australia. The survey canvassed practitioners’ perspectives on local provenancing, genetic diversity and other aspects of restoration that have the potential to influence the long‐term success of restored rainforest communities. All respondents to this survey typically included a planting component in their restoration projects (whether for reconstruction or to supplement assisted regeneration). Planting represents an anthropogenic selection and translocation of genotypes to a restoration site. As a result, considerations of genetic origin and the potential implications to the restored rainforest community are relevant to most restoration projects. This industry survey's results showed that genetic diversity and local provenancing are concepts of importance to practitioners. However, there seems to be a lack of clarity within the industry about how to define local provenance and how the concepts of local provenancing and genetic diversity influence each other. The results indicated that local provenancing remains the preferred provenancing strategy amongst practitioners, with inclusion of non‐local provenance seed not regarded as an effective means of improving genetic diversity. This is despite researchers highlighting the limitations of local provenancing, particularly in highly fragmented landscapes, and despite the publication of numerous alternative provenancing strategies. Rainforest restoration may benefit from practitioners questioning the appropriateness of local provenancing to their restoration projects and considering that in some circumstances exclusive reliance on local provenance stock may in fact be worse, not better, for the long‐term sustainability of restored communities.  相似文献   

19.
Local adaptation experiments are widely used to quantify the levels of adaptation within a heterogeneous environment. However, theoretical studies generally focus on the probability of fixation of alleles or the mean fitness of populations, rather than local adaptation as it is commonly measured experimentally or in field studies. Here, we develop mathematical models and use them to generate analytical predictions for the level of local adaptation as a function of selection, migration and genetic drift. First, we contrast mean fitness and local adaptation measures and show that the latter can be expressed in a simple and general way as a function of the spatial covariance between population mean phenotype and local environmental conditions. Second, we develop several approximations of a population genetics model to show that the system exhibits different behaviours depending on the rate of migration. The main insights are the following: with intermediate migration, both genetic drift and migration decrease local adaptation; with low migration, drift decreases local adaptation but migration speeds up adaptation; with high migration, genetic drift has no effect on local adaptation. Third, we extend this analysis to cases where the trait under selection is continuous using classical quantitative genetics theory. Finally, we discuss these results in the light of recent experimental work on local adaptation.  相似文献   

20.
ABSTRACT: Gender is one of the main variables that influence the distribution of local knowledge. We carried out a literature review concerning local mycological knowledge, paying special attention to data concerning women's knowledge and comparative gender data. We found that unique features of local mycological knowledge allow people to successfully manage mushrooms. Women are involved in every stage of mushroom utilization from collection to processing and marketing. Local mycological knowledge includes the use mushrooms as food, medicine, and recreational objects as well as an aid to seasonal household economies. In many regions of the world, women are often the main mushroom collectors and possess a vast knowledge about mushroom taxonomy, biology, and ecology. Local experts play a vital role in the transmission of local mycological knowledge. Women participate in the diffusion of this knowledge as well as in its enrichment through innovation. Female mushroom collectors appreciate their mycological knowledge and pursue strategies and organization to reproduce it in their communities. Women mushroom gatherers are conscious of their knowledge, value its contribution in their subsistence systems, and proudly incorporate it in their cultural identity.  相似文献   

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