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1.
Local communities play an increasingly important role in the management and conservation of forests at local and global scales. Conventional analyses of community forest management tend to view the outcomes of these efforts, as with common pool resources (CPRs) more generally, as contingent on the ability of local institutions to control collective levels of extractive use and enforce group rules. This paper provides a case study of a community forest in southern Michigan, in the Midwestern United States, that challenges these assumptions about community-based forest management. The factors driving change in this forest are not tied to excessive extraction or disturbance by human agents but rather the proliferation of shade-tolerant invasive species. The community institutions and values that made it possible for the forest to grow and mature now threaten its very existence. By discouraging any form of active management, the forest has become susceptible to the growing pressures of human-induced environmental change such as the introduction of exotic plant species. Biodiversity conservation in such contexts consequently relies not only on restraining local forest utilization practices or the preservation of land from development, but on active management interventions by local forest users. Understanding the impact of community management on CPRs in human-dominated ecosystems will require broadening the scope of analysis to account for the importance of active management and the potentially deleterious effects of preservationist approaches on native biota.
Fred NelsonEmail:
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2.
The discussion about the impact of pastoralists on ecosystems has been profoundly shaped by Hardin’s tragedy of the commons that held pastoralists responsible for overgrazing the range. Research has shown that grazing ecosystems are much more complex and dynamic than was previously assumed and that they can be managed adaptively as commons. However, proponents and critics of Hardin’s thesis continue to argue that open access to common-pool resources inevitably leads to a tragedy of the commons. A longitudinal study that we conducted of pastoral mobility and primary production in the Logone floodplain in the Far North Region of Cameroon suggest that open access does not have to lead to a tragedy of the commons. We argue that this pastoral system is best conceptualized as an open system, in which a combination of individual decision-making and coordination of movements leads to an ideal-free type of distribution of mobile pastoralists. We explain how this self-organizing system of open access works and its implications for theories of management of common-pool resources and our understanding of pastoral systems.  相似文献   

3.
4.
This study focuses on individuals’ subjective reasons for complying with rules for common pool resource management. We examine the topic of individual rule compliance, which the commons literature has addressed only marginally, and outline recent empirical findings. Hypotheses are derived based on rule compliance theory and explored using data gathered in a Cuban community sharing a solar energy system. The statistical analyses reveal that compliance with rules for energy management is influenced by various factors. Depending on the particular rule, factors such as sanctioning, legitimacy, and compatibility, among others, influence the frequency of individual rule compliant behavior to differing extents.  相似文献   

5.
Jo?o Queiroz 《Biosemiotics》2012,5(3):319-329
Against the view that symbol-based semiosis is a human cognitive uniqueness, we have argued that non-human primates such as African vervet monkeys possess symbolic competence, as formally defined by Charles S. Peirce. Here I develop this argument by showing that the equivocal role ascribed to symbols by ??folk semiotics?? stems from an incomplete application of the Peircean logical framework for the classification of signs, which describes three kinds of symbols: rheme, dicent and argument. In an attempt to advance in the classifying semiotic processes, Peirce proposed several typologies, with different degrees of refinement. Around 1903, he developed a division into ten classes. According to this typology, symbols can be further analysed in three subclasses (rheme, dicent, argument). I proceed to demonstrate that vervet monkeys employ dicent symbols. There are remarkable implications of this argument since ??symbolic species theory?? fails to explore the vast Peircean semiotic philosophy to frame questions regarding the emergence and evolution of symbolic processes.  相似文献   

6.

Context

Identifying patients at risk for adverse outcomes of Clostridium difficile infection (CDI), including recurrence and death, will become increasingly important as novel therapies emerge, which are more effective than traditional approaches but very expensive. Clinical prediction rules (CPRs) can improve the accuracy of medical decision-making. Several CPRs have been developed for CDI, but none has gained a widespread acceptance.

Methods

We systematically reviewed studies describing the derivation or validation of CPRs for unfavourable outcomes of CDI, in medical databases (Medline, Embase, PubMed, Web of Science and Cochrane) and abstracts of conferences.

Results

Of 2945 titles and abstracts screened, 13 studies on the derivation of a CPR were identified: two on recurrences, five on complications (including mortality), five on mortality alone and one on response to treatment. Two studies on the validation of different severity indices were also retrieved. Most CPRs were developed as secondary analyses using cohorts assembled for other purposes. CPRs presented several methodological limitations that could explain their limited use in clinical practice. Except for leukocytosis, albumin and age, there was much heterogeneity in the variables used, and most studies were limited by small sample sizes. Eight models used a retrospective design. Only four studies reported the incidence of the outcome of interest, even if this is essential to evaluate the potential usefulness of a model in other populations. Only five studies performed multivariate analyses to adjust for confounders.

Conclusions

The lack of weighing variables, of validation, calibration and measures of reproducibility, the weak validities and performances when assessed, and the absence of sensitivity analyses, all led to suboptimal quality and debatable utility of those CPRs. Evidence-based tools developed through appropriate prospective cohorts would be more valuable for clinicians than empirically-developed CPRs.  相似文献   

7.
This paper investigates the impact of human out-migration on long-standing commons institutions in the Sierra Norte of Oaxaca. Local communities have been increasingly engaged with national and international markets for wage labour, with many losing a significant percentage of their resident populations. This paper shows how demographic and cultural change is impacting the two social institutions—cargos and tequios—that underpin the highly autonomous form of governance the region is famed for. The loss of able-bodied men and women has meant that these customary systems are struggling to remain operational. A number of responses and institutional adaptations have been introduced by community authorities, including the forging of translocal ties that show potential for reducing the vulnerability of affected villages. While migration was temporary or circular from the 1970s to the 1990s, more permanent forms of migration have come to dominate since that time. Such a shift undermines adaptation efforts at the community level. Within this context, the lessons for commons theory are discussed, while a new layer of complexity is added to the body of work examining the consequences of rural depopulation on Mexican village life and landscapes.  相似文献   

8.
Nitrogen (N) fertiliser management is increasingly important in sugarcane production as imperatives to reduce environmental impacts of N escalate. In this paper we report testing of a new concept for N management in sugarcane, the N Replacement system. This system relies on soil N cycling to ??buffer?? differences in crop N needs and N fertiliser supply to individual crops, and aligns N applications with actual cane production over the longer-term rather than potential production. In 11 experiments, conducted in a wide range of environments over two to five crops, cane and sugar yields in the N Replacement treatment were similar to those achieved with the farmers?? conventional N management, with a trend over successive crops for yields to increase relative to conventional management. At sites where experiments ran for at least 4 years, this trend resulted in cumulative sugar yields being higher in the N Replacement treatment. Average N applications were 35% lower in the N Replacement treatment, and N lost to the environment was estimated to be ??50% lower. Soil N ??buffering?? was adequate to maintain sufficient N supply to crops even when yields were up to 30% greater than expected. Thus, it is not necessary to align fertiliser applications to potential sugarcane yields, which are rarely achieved in practice. Our results show that the ecologically-based N Replacement system has promise to deliver superior environmental outcomes without significantly reducing production of sugarcane, and potentially other semi-perennial crops, in the tropics and subtropics. Further evaluation of the system will be beneficial, and there is scope for determining more site-specific values of parameters in the system. However, care must be taken to evaluate the system over sufficient time frames (e.g. >2 crops) so that productivity improvement trends in the N Replacement system can be expressed.  相似文献   

9.
Biodiversity and stakeholder participation   总被引:1,自引:0,他引:1  
Consensus building through stakeholder participation is a promising new trend that takes into account the interactive character of the communication process. There is a growing realisation that stakeholder participation has a significant role to play in the development and delivery of biodiversity policy and practice. Experience and best practice from activities such as the designation and management of Natura 2000 and Integrated Coastal Zone Management shows that problem solving and conflict management are significantly enhanced through participative processes. There is therefore the potential for a change to take place in the way that biodiversity policy is developed and implemented. This brings challenges to the biodiversity community in terms of developing new skills and processes and in engaging with new agendas and sectors.  相似文献   

10.
Multidisciplinary Approaches to Natural Resource Management   总被引:1,自引:1,他引:0  
Counter-acting forces to increase rural production and/or its efficiency, and to sustain an ecosystem now recognised to be under increasing and destructive pressures have created exigencies in achieving balanced natural resource management (NRM). Nowhere is this more apparent than in the management of the Murray Darling System in south-eastern Australia. All actions affecting natural resources impinge on the ecosystems that support those resources, the economy based on them, and the human society and culture connected to them. Change is best managed with the cooperation of those most affected. If NRM is to be achieved through informed community decisions, there is a need for a multidisciplinary process, drawing on specialist (intra-disciplinary) expertise, and a requirement to pull the resultant knowledge into an integrated form which supports decision-making at the management and community level. We propose a framework that identifies tasks necessary to support community decision-making and inject specialist technical knowledge into the process. For complex NRM issues, it is likely that there is insufficient information in one or more disciplines to support a strong decision. Where possible, this should lead to the interposition of targeted pilot trials, based on principles of adaptive management, prior to the final assessment and (presumedly) management plans. These ‘management experiments’ follow a similar path to specialist hypotheses and measurements (based on the same management intervention) followed by an integrated assessment. It appears that identification of, and engagement with, components of the community, and analytical techniques to support integrated assessment are two major areas in which new knowledge is urgently needed.  相似文献   

11.
Contemporary theoretical accounts of common pool resource management assume that communities are able to develop institutions for sustainable resource management if they are given security of access and appropriate rights of management. In recent years comprehensive legal reforms of communal rural resource management in Namibia have sought to create an institutional framework linking the sustainable use of natural resources (game, water, forest) and rural development. The state, however, ceded rights to rural communities in an ambiguous and fragmented manner, creating a number of instances of overlapping property rights and different legal conditions for different natural resources. Nowadays communities grapple with the challenge of developing institutions for these resource-centered “new commons”. This paper describes the process of local institutional development, focusing on the challenges arising from the necessity to define group boundaries, the issues arising from monitoring and sanctioning within newly defined institutions, and the ideological underpinnings of different trajectories of communal resource management.  相似文献   

12.
This study describes the symbolic process by which individuals attempted to realize, in organizational form, their variant interpretations of an extended metaphor—community mental health. Their metaphoric construals were embedded in everyday discourse and were initially unrecognized by participants at a community mental health center. The metaphoric process, that is, the movement involving the emergence, interpretation, and realization of these metaphors, was mediated by the self-images of the participants. They had embarked upon an innovative project to realize, in part, an ideal sense of self. The latter was a key factor in the development of new construals of community mental health and the implementation of these construals. [metaphor, symbolic process, self, mental health]  相似文献   

13.
Informed by anthropologist Stephen Gudeman’s dialect between the interacting realms of community and market economies, I seek in this article to focus on aspects of the commons and the shared values of a community that might be referred to as the ‘spiritual commons’. The phrase speaks specifically to the ideas and practices that guide the ritual and spiritual elements of social life. I argue that the spiritual commons is not a realm set apart from economic life but integral to its reproduction. Gift exchange, sacrifice and commensality enacted as expressions of religious sociality represent economies of symbolic goods that serve both material and ideational ends. The article draws upon ethnographies of eastern Indonesia and the comparative possibilities expressed in case studies from Islamic southeast Sulawesi and Catholic Flores.  相似文献   

14.
A replicate long-term experiment was conducted using anaerobic digestion (AD) as a model process to determine the relative role of niche and neutral theory on microbial community assembly, and to link community dynamics to system performance. AD is performed by a complex network of microorganisms and process stability relies entirely on the synergistic interactions between populations belonging to different functional guilds. In this study, three independent replicate anaerobic digesters were seeded with the same diverse inoculum, supplied with a model substrate, α-cellulose, and operated for 362 days at a 10-day hydraulic residence time under mesophilic conditions. Selective pressure imposed by the operational conditions and model substrate caused large reproducible changes in community composition including an overall decrease in richness in the first month of operation, followed by synchronised population dynamics that correlated with changes in reactor performance. This included the synchronised emergence and decline of distinct Ruminococcus phylotypes at day 148, and emergence of a Clostridium and Methanosaeta phylotype at day 178, when performance became stable in all reactors. These data suggest that many dynamic functional niches are predictably filled by phylogenetically coherent populations over long time scales. Neutral theory would predict that a complex community with a high degree of recognised functional redundancy would lead to stochastic changes in populations and community divergence over time. We conclude that deterministic processes may play a larger role in microbial community dynamics than currently appreciated, and under controlled conditions it may be possible to reliably predict community structural and functional changes over time.  相似文献   

15.

Purpose

In an effort to develop a whole building Life Cycle Assessment (LCA) tool, National Institute of Standards and Technology (NIST) is transforming new bottom-up Building for Environmental and Economic Sustainability (BEES) data into a hybrid database in which the strengths of both bottom-up and top-down approaches can be combined. The objective of this paper is to describe the framework and the process under which the hybrid BEES database is being built, with an emphasis on its accounting structure. This paper can support other efforts to build hybrid Life Cycle Inventory (LCI) databases.

Methods

The BEES hybridization utilizes the most detailed supply and use tables (SUTs)??known as item-level data??focusing particularly on the construction sectors. First, the partial SUTs at the item level are constructed and connected to standard SUTs that describe the rest of the economy, which is then followed by balancing and ??redefinition.?? Second, item-level environmental data are compiled and then also balanced and redefined, which completes the compilation of the bi-resolution SUTs with environmental data. Third, the bi-resolution SUTs are integrated with the BEES data that have been converted into matrix form. Because the completely rolled out BEES technology matrix involves a significant number of products, the integration prioritizes the product groups that are potentially the most significant contributors to the LCIA results for buildings.

Results

This step-by-step procedure will enable the creation of a hybridized BEES database, combining the strengths of both the bottom-up, process-based data and the top-down, input-output data with enhanced resolution. The benefit of hybridization at the database level??as opposed to at the individual LCA study level??is that whole-building LCA users can adopt the hybrid BEES approach, with its benefit of a more complete system definition, without the training or effort that would be required to construct a hybrid system from scratch. In addition, reformulation of new BEES data into a matrix structure better facilitates the parametric LCA application that is central to NIST??s vision to develop a tool for assessing the sustainability performance of energy technologies and systems in an integrated building design context.

Conclusions

There are currently a number of initiatives being organized to implement a hybrid approach at the LCI database level. In laying out the methodological framework for efficiently transforming an existing LCI database into a hybrid database, this paper can support future development of hybrid LCI databases.  相似文献   

16.

Background

Diagnostic clinical prediction rules (CPRs) are developed to improve diagnosis or decrease diagnostic testing. Whether, and in what situations diagnostic CPRs improve upon clinical judgment is unclear.

Methods and Findings

We searched MEDLINE, Embase and CINAHL, with supplementary citation and reference checking for studies comparing CPRs and clinical judgment against a current objective reference standard. We report 1) the proportion of study participants classified as not having disease who hence may avoid further testing and or treatment and 2) the proportion, among those classified as not having disease, who do (missed diagnoses) by both approaches. 31 studies of 13 medical conditions were included, with 46 comparisons between CPRs and clinical judgment. In 2 comparisons (4%), CPRs reduced the proportion of missed diagnoses, but this was offset by classifying a larger proportion of study participants as having disease (more false positives). In 36 comparisons (78%) the proportion of diagnoses missed by CPRs and clinical judgment was similar, and in 9 of these, the CPRs classified a larger proportion of participants as not having disease (fewer false positives). In 8 comparisons (17%) the proportion of diagnoses missed by the CPRs was greater. This was offset by classifying a smaller proportion of participants as having the disease (fewer false positives) in 2 comparisons. There were no comparisons where the CPR missed a smaller proportion of diagnoses than clinical judgment and classified more participants as not having the disease. The design of the included studies allows evaluation of CPRs when their results are applied independently of clinical judgment. The performance of CPRs, when implemented by clinicians as a support to their judgment may be different.

Conclusions

In the limited studies to date, CPRs are rarely superior to clinical judgment and there is generally a trade-off between the proportion classified as not having disease and the proportion of missed diagnoses. Differences between the two methods of judgment are likely the result of different diagnostic thresholds for positivity. Which is the preferred judgment method for a particular clinical condition depends on the relative benefits and harms of true positive and false positive diagnoses.  相似文献   

17.
Port-state jurisdiction has been used as a means of circumventing the inadequacies of enforcement on the high seas and of flag states’ ineffectiveness, but also the absence of international rules due to lack of consensus at the international level. Pressing and complex problems related to the global environment and global commons, such as depletion of fisheries, marine and atmosphere pollution, and climate change, and foot-dragging in the international community to effectively cooperate to tackle these problems have brought the concept of unilateral regulation of extraterritorial activities to the forefront. In this respect, the role of the port state, as a first point of contact for industries engaged in activities harmful to the global commons (i.e., fishing and shipping), is increasingly important. This article examines the scope and limits of port-state jurisdiction with respect to measures that may have an extraterritorial impact in the light of the law of the sea and international rules on jurisdiction. The aim of the article is to assess whether the practice of port states in exercising jurisdiction has contributed to developments regarding the exercise of (extraterritorial) jurisdiction as a regulatory tool for the protection of global commons. By identifying elements of current state practice regarding exercise of port-state jurisdiction, the article advances a framework for the most effective exercise of port-state jurisdiction for the protection of global commons with reference to the principle of common concern.  相似文献   

18.
Soil and crop management strategies to prevent iron deficiency in crops   总被引:5,自引:0,他引:5  
Plants and humans cannot easily acquire iron from their nutrient sources although it is abundant in nature. Thus, iron deficiency is one of the major limiting factors affecting crop yields, food quality and human nutrition. Therefore, approaches need to be developed to increase Fe uptake by roots, transfer to edible plant portions and absorption by humans from plant food sources. Integrated strategies for soil and crop management are attractive not only for improving growing conditions for crops but also for exploiting a plant??s potential for Fe mobilization and utilization. Recent research progress in soil and crop management has provided the means to resolve complex plant Fe nutritional problems through manipulating the rhizosphere (e.g., rhizosphere fertilization and water regulation), and crop management (includes managing cropping systems and screening for Fe efficient species and varieties). Some simple and effective soil management practices, termed ??rhizosphere fertilization?? (such as root feeding and bag fertilization) have been developed and widely used by local farmers in China to improve the Fe nutrition of fruit plants. Production practices for rice cultivation are shifting from paddy-rice to aerobic rice to make more efficient use of irrigation water. This shift has brought about increases in Fe deficiency in rice, a new challenge depressing iron availability in rice and reducing Fe supplies to humans. Current crop management strategies addressing Fe deficiency include Fe foliar application, trunk injection, plant breeding for enriched Fe crop species and varieties, and selection of cropping systems. Managing cropping systems, such as intercropping strategies may have numerous advantages in terms of increasing Fe availability to plants. Studies of intercropping systems on peanut/maize, wheat/chickpea and guava/sorghum or -maize increased Fe content of crops and their seed, which suggests that a reasonable intercropping system of iron-efficient species could prevent or mitigate Fe deficiency in Fe-inefficient plants. This review provides a comprehensive comparison of the strategies that have been developed to address Fe deficiency and discusses the most recent advance in soil and crop management to improve the Fe nutrition of crops. These proofs of concept studies will serve as the basis for future Fe research and for integrated and optimized management strategies to alleviate Fe deficiency in farmers?? fields.  相似文献   

19.
It is well known that predation/harvesting on a species subjected to an infectious disease can affect both the infection prevalence and the population dynamics. In this paper, I model predator?Cprey?Cpathogen interactions in the case where the presence of a predator indirectly affects the transmission rate of the infection in its prey. I call this phenomenon the predator-dependent disease transmission. Such a scenario can arise, for example, as a consequence of anti-predator defence behaviour, debilitating the immune system of the prey. Although being well documented, the predator-dependent disease transmission has rarely been taken into account in ecoepidemiological models. Mathematically, I consider a classical S-I-P ecoepidemiological model in which the infected and/or the healthy host can be consumed by a predator where the coefficient in the mass action transmission term is predator-dependent. Investigation of the model shows that including such a predator-dependent disease transmission can have important consequences for shaping predator?Cprey?Cpathogen interactions. In particular, this can enhance the survival of the predator, restricted in a system with a predator-independent disease transmission. I demonstrate the emergence of a disease-mediated strong Allee effect for the predator population. I also show that in the system with predator-dependent disease transmission, the predator can indirectly promote epidemics of highly virulent infectious diseases, which would die out in a predator-free system. Finally, I argue that taking into account predator-dependent disease transmission can have a destabilizing effect in a eutrophic environment, which can potentially cause the extinction of both species. I also show that including the predator-dependent disease transmission may increase the infection prevalence, and this fact will question the ??keeping herds healthy?? hypothesis concerning the management of wildlife infections by natural predators.  相似文献   

20.
Complexity and Transition Management   总被引:1,自引:0,他引:1  
This article presents a framework, transition management, for managing complex societal systems. The principal contribution of this article is to articulate the relationship between transition management and complex systems theory. A better understanding of the dynamics of complex, adaptive systems provides insight into the opportunities, limitations, and conditions under which it is possible to influence such systems. Transition management is based on key notions of complex systems theory, such as variation and selection, emergence, coevolution, and self-organization. It involves a cyclical process of phases at various scale levels: stimulating niche development at the micro level, finding new attractors at the macro level by developing a sustainability vision, creating diversity by setting out experiments, and selecting successful experiments that can be scaled up.  相似文献   

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