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1.
The sustainable use of resources requires that management practices and institutions take into account the dynamics of the ecosystem. In this paper, we explore the role of local ecological knowledge and show how it is used in management practices by a local fishing association in a contemporary rural Swedish community. We focus on the local management of crayfish, a common-pool resource, and also address the way crayfish management is linked to institutions at different levels of Swedish society. Methods from the social sciences were used for information gathering, and the results were analyzed within the framework of ecosystem management. We found that the practices of local fishing association resemble an ecosystem approach to crayfish management. Our results indicate that local users have substantial knowledge of resource and ecosystem dynamics from the level of the individual crayfish to that of the watershed, as reflected in a variety of interrelated management practices embedded in and influenced by institutions at several levels. We propose that this policy of monitoring at several levels simultaneously, together with the interpretation of a bundle of indicators and associated management responses, enhances the possibility of building ecological resilience into the watershed. Furthermore, we found that flexibility and adaptation are required to avoid command-and-control pathways of resource management. We were able to trace the development of the local fishing association as a response to crisis, followed by the creation of an opportunity for reorganization and the recognition of slow ecosystem structuring variables, and also to define the role of knowledgeable individuals in the whole process. We discuss the key roles of adaptive capacity, institutional learning, and institutional memory for successful ecosystem management and conclude that scientific adaptive management could benefit from a more explicit collaboration with flexible community-based systems of resource management for the implementation of policies as experiments. Received 26 April 2000; accepted 13 October 2000.  相似文献   

2.
There are two broadly conceptualized ways in which conservation knowledge may evolve: the depletion crisis model and the ecological understanding model. The first one argues that developing conservation thought and practice depends on learning that resources are depletable. Such learning typically follows a resource crisis. The second mechanism emphasizes the development of conservation practices following the incremental elaboration of environmental knowledge by a group of people. These mechanisms may work together. Following a perturbation, a society can self-organize, learn and adapt. The self-organizing process, facilitated by knowledge development and learning, has the potential to increase the resilience (capability to absorb disturbance and reorganize while undergoing change) of resource use systems. Hence, conservation knowledge can develop through a combination of long-term ecological understanding and learning from crises and mistakes. It has survival value, as it increases the resilience of integrated social--ecological systems to deal with change in ways that continue to sustain both peoples and their environments.  相似文献   

3.
How can decision makers reconcile the demand for increasingly reliable services drawn from the environment (including water and power) with the desire for both a better environment and more environmental amenities? In this paper, which is based on US case studies of ecosystem rehabilitation initiatives in the San Francisco Bay-Delta, the Columbia River Basin in the Pacific Northwest, and the Florida Everglades, we focus on several notable problems in current management practice. We assess the role of adaptive management and identify five areas of major innovation by which ecologists and the authorities that operate large water and hydropower systems attempt to reconcile the tension between maintaining service reliability and promoting ecological rehabilitation. The implications of the findings for a wider framework within which ecosystems can be matched to the most appropriate management regime are related specifically to aquatic-terrestrial ecosystems. Finally, we emphasize the importance of redefining ecosystem functions and services so that the inherent conflict between high-reliability services and ecosystem rehabilitation can be reconciled.  相似文献   

4.
Ecosystem stability and the response of ecosystems to disturbance are of crucial importance for conservation management, especially when the object is to maintain and/or to restore early-successional communities. This paper provides a selective review of ecosystem stability from a conservation perspective. Existing models of ecosystem resilience are discussed in relation to the management of successional habitats. A multivariate model for measuring stability and resilience based on Canonical Correspondence Analysis (CCA) is outlined. The criteria for the model to work are explained and the model is tested on vegetation and soil data from the Dorset Heaths. The model provides a mechanism for bringing together measurements of both structure (species composition) and function (ecosystem properties, both biotic and abiotic), to measure stability and resilience of ecosystems. The model can also be used to measure the success of management in restoring communities and to provide information to conservation policy makers and land managers.  相似文献   

5.
We have obtained frameshift mutations of the bacteriophage T4 gene 67 by manipulating restriction cleavage sites within the gene cloned onto small plasmids. When these mutated genes were recombined back into the T4 genome the resulting phages were inviable. They could only be propagated by complementation in strains carrying a cloned, non-mutated copy of the gene on a plasmid. These experiments demonstrate that gene 67 is essential for T4 growth. Electron microscopy of bacteria infected with 67? phages revealed that phage head morphogenesis was blocked at an early stage and particles resembling abnormal preheads were found in large numbers. The gene 67 product, PIP, is therefore essential for correct prehead assembly.  相似文献   

6.
 For effective mitigation of human impacts, quantitative models are required that facilitate a comprehensive analysis of the effects of human activity on reefs. Fuzzy logic procedures generate a complex dose-response surface that models the relationships among coral abundance and various inputs (e.g., physical damage, sedimentation, nutrient influx), within the context of the abiotic marine environment. This is linked to a nonlinear economic structure incorporating technical interventions (e.g., pollution treatment) and policy interventions (e.g., taxation) in eight economic sectors. Optimization provides insights into the most cost-effective means for protecting coral reefs under different reef quality targets. The research demonstrates that: (1) it is feasible to use fuzzy logic to model complex interactions in coral reef ecosystems; and, (2) conventional economic procedures for modeling cost-effectiveness can result in sub-optimal policy choices when applied to complex systems such as coral reefs. In Montego Bay, Jamaica, up to a 20% increase in coral abundance may be achievable through using appropriate policy measures having a present value cost of US$153 million over 25 years; a 10% increase is achievable at a cost of US$12 million. Accepted: 20 June 1999  相似文献   

7.
The two-phase life history of most marine fishes and invertebrates has enormous implications for dispersal, population connectivity, and resource management. Pelagic dispersal larvae of marine animals traditionally thought to ensure that populations are widespread, that chances of local extinction are low, and that marine protected areas (MPA) can easily function to replenish both their own populations and those of unprotected areas. Traditionally, dispersal is considered to depend primarily on two variables: pelagic larva duration and far-field currents. These conclusions arise from the open population paradigm and are usually accompanied by a simplifying assumption: larvae are distributed passively by far-field currents. Unfortunately, they ignore the complex reality of circulation and hydrological connectivity of reefs, and do not consider newly-demonstrated behavioural capabilities of coral-reef fish larvae. Far-field circulation varies with depth and often excludes water bodies where propagules are released, and this has important implications for predicting trajectories of even passive larvae. However, larvae are not passive: late-stage larvae of coral-reef fishes can swim faster than currents for long periods, can probably detect reefs at some distance, and can actively find them. This behaviour is flexible, which greatly complicates modelling of larval fish trajectories. Populations at ecological (as opposed to evolutionary) scales are probably less open and more subdivided than previously assumed. All this means that dispersal predictions based solely on far-field water circulation are probably wrong. An emerging view of larval-fish dispersal is articulated that takes these new data and perspectives into account. This emerging view shows that re-evaluation of traditional views in several areas is required, including the contribution of larval-fish biology and dispersal to biodiversity patterns, the way reef fishes are managed, and the way in which MPA are thought to operate. At evolutionary and zoogeographic scales, reef-fish populations are best considered to be open.  相似文献   

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