“双碳”背景下碳排放的边际外部性成本及最佳碳税的思考

气候变暖与环境恶化已成为人类生存和发展的重大威胁。鉴于碳排放具有负外部性,研究碳排放的边际外部性成本并探究最佳碳税,对于推进实现“双碳”目标具有重要意义。本文通过构建一个无限期的多部门新古典增长模型,探究碳排放的边际外部性成本及其影响因素,并对最优的碳税政策进行思考。研究结果表明：当居民消费效用函数呈对数形式、大气损害与产量成正比、大气中的碳含量存在线性关系和储蓄率不变等假设条件成立时,碳排放的边际外部性成本与产出成正比,且比例只与贴现率、大气损害函数和大气中的碳消散结构有关。因此,在碳税政策的制定上,要坚持经济发展与生态环境保护并重,分阶段动态优化调整碳税税率：在高贴现率时期提高碳税税率,分行业施行碳税政策和补贴政策,同时为了避免经济社会遭受到较大的冲击,起初征收碳税时税率不宜过高;考虑不同体量企业收入差距和负担能力,采用累进碳税征收机制;分地区实施差别税率,统筹区域协调发展。     

Integrating forage,wildlife, water,and fish projections with timber projections at the regional level: A case study in southern United States

The impact of timber management and land-use change on forage production, turkey and deer abundance, red-cockaded woodpecker colonies, water yield, and trout abundance was projected as part of a policy study focusing on the southern United States. The multiresource modeling framework used in this study linked extant timber management and land-area policy models with newly developed models for forage, wildlife, fish, and water. Resource production was integrated through a commonly defined land base that could be geographically partitioned according to individual resource needs. Resources were responsive to changes in land use, particularly human-related, and timber management, particularly the harvest of older stands, and the conversion to planted pine.     

野生动植物及其产品交易市场存在的问题及对策分析

分析了当前我国野生动植物利用产业发展所显现的资源培育产业发展迅速、企业规模化和集约化发展趋势明显、进口贸易激增等特征，对我国野生动植物及其产品的交易市场现状及其存在的非法交易多、市场杂乱、监管难度大等问题进行了深入分析，提出构建野生动植物及其产品专业市场体系和野生动植物及其产品的标记体系相结合的监管制度的政策建议。     

Passive and active adaptive management: approaches and an example

Adaptive management is a framework for resource conservation that promotes iterative learning-based decision making. Yet there remains considerable confusion about what adaptive management entails, and how to actually make resource decisions adaptively. A key but somewhat ambiguous distinction in adaptive management is between active and passive forms of adaptive decision making. The objective of this paper is to illustrate some approaches to active and passive adaptive management with a simple example involving the drawdown of water impoundments on a wildlife refuge. The approaches are illustrated for the drawdown example, and contrasted in terms of objectives, costs, and potential learning rates. Some key challenges to the actual practice of AM are discussed, and tradeoffs between implementation costs and long-term benefits are highlighted.     

BIOLOGICAL AND ECONOMIC IMPLICATIONS OF SACRAMENTO WATERSHED MANAGEMENT OPTIONS1

ABSTRACT: This paper brings together spatially and temporally explicit mechanistic models of hydrodynamic, water quality, and ecological processes with an economic model to examine water management alternatives for California's Sacramento River and Delta ecosystem, a large‐scale watershed. Overallocated water supplies in most years, combined with increasing demand for water for environmental purposes, have created a politically charged atmosphere and a need for quantitative assessment of the implications of policy alternatives. By developing and analyzing a common set of policy scenarios, this integrated framework allows us to consider tradeoffs between agricultural economic factors, water quality, and population dynamics for two at‐risk fish species. We analyze two rather extreme types of policy options; one involves structural modifications to change the flow of water within the watershed but no change in water diversions, while the other reallocates water from agricultural users to fish and wildlife. Results suggest that substantial environmental improvements could be made at a relatively modest cost to farmers (1 to 4 percent reductions in revenues) but that those costs could be significant locally. In addition to tradeoffs between farmers and environmental interests, results suggest that policy makers may need to balance competing environmental objectives.     

SOIL EROSION AND GROUND WATER POLLUTION TRADEOFFS FOR NONIRRIGATED FARMING SYSTEMS1

ABSTRACT: Traditional focus on reducing one environmental externality may cause another externality to increase. This article examines the environmental and economic costs of abating soil loss and (or) nitrate leaching through alternative optimal production systems in the nonirrigated farming systems of Northeastern Oregon. Models estimating soil loss and nitrate‐nitrogen leaching rates associated with current production processes, are linked to a Multi‐Objective Programming (MOP) model. The results show that site specific conditions influence the level of abatement expenditures and optimal production strategies to reduce soil loss and leaching rates. Moreover, while existing production strategies are effective in reducing soil loss at little cost, no strategies could be identified to reduce nitrate leaching rate on some soils.     

Evaluating internalization of multifunctionality by farm diversification: evidence from educational dairy farms in Japan

Farm diversification by farmers' open-door policy generates opportunities for farmers to internalize externalities of multifunctionality. Although the educational function of agriculture is an example of such an open-door policy and is attracting growing attention, this function has been little explored. To promote farm diversification in this direction, this paper examined how and to what degree farmers internalize externalities of multifunctionality by focusing on the educational function provided by dairy farming, i.e., farming experience services, in Japan. The main findings were as follows. First, we can say that the educational function is determined by ordinary technical jointness as well as institutional jointness, which is represented by food culture and the agrarian heritage. Both the technical and institutional jointness enhanced the externality. Because of these two working factors, there is a U-shaped relationship between farm diversification and provision of farming experience services. Second, however, an empirical evaluation indicated that farmers only partially internalize educational externalities by treating them as supplementary services combined with processed milk products. Therefore, appropriate integrated management of these newly emerging educational services to become a viable market should be fully addressed in the future, especially for family farms.     

Using Wildlife as Receptor Species: A Landscape Approach to Ecological Risk Assessment

To assist risk assessors at the Department of Energy’s Savannah River Site (SRS), a Geographic Information System (GIS) application was developed to provide relevant information about specific receptor species of resident wildlife that can be used for ecological risk assessment. Information was obtained from an extensive literature review of publications and reports on vertebrate- and contaminant-related research since 1954 and linked to a GIS. Although this GIS is a useful tool for risk assessors because the data quality is high, it does not describe the species’ site-wide spatial distribution or life history, which may be crucial when developing a risk assessment. Specific receptor species on the SRS were modeled to provide an estimate of an overall distribution (probability of being in an area). Each model is a stand-alone tool consisting of algorithms independent of the GIS data layers to which it is applied and therefore is dynamic and will respond to changes such as habitat disturbances and natural succession. This paper describes this modeling process and demonstrates how these resource selection models can then be used to produce spatially explicit exposure estimates. This approach is a template for other large federal facilities to establish a framework for site-specific risk assessments that use wildlife species as endpoints.Current address: Biology Department, University of South Dakota, Vermillion, SD 57069     

Component modeling for the spatial representation of wildlife movements

This paper has two main objectives: (1) to discuss the basics of component modeling and its conceptual implications in environmental modeling; and (2) based on this discussion, to present a component-based design to support the simulation of wildlife movements. Components are independently developed, ready-to-use software units that can be assembled together to construct a modeling system. The conceptual implications of component modeling for the representation of environmental phenomena are discussed. A comparison is made between these conceptual implications and those of the more familiar object-oriented approach. A component-based design for supporting the simulation of wildlife movements is presented in this paper in order to illustrate how component modeling can be used to support the spatial representation of ecological phenomena and processes.     

SIMULATION AND DECISIONMAKING: THE PLATTE RIVER BASIN IN NEBRASKA1

Substantial conflict exists over water management and allocation in the Platte River Basin of Nebraska. An interdisciplinary computer simulation model, representing the water quantity, water quality, environmental, and economic dimensions of the conflict, was developed in order to analyze the tradeoffs among allocation scenarios. Most importantly, decisionmakers and interest groups were involved in model development. Simulation results for a base case and two scenarios are presented. One scenario favors protection of instream flow for wildlife; the other favors water diversions for agriculture. Impacts of the instream flow scenario, as measured by the amount of land irrigated, groundwater levels, the amount of wildlife habitat for cranes and catfish, and net agricultural benefits did not differ greatly from those of the base case. However, impacts of the diversion scenario were substantial. On the negative side, instream flows and wildlife habitat declined an average of 39 percent; while, on the positive side, groundwater levels and net agricultural benefits each increased 6 percent. The modeling process was successful insofar as it promoted an understanding among the highly diverse interest groups of the systems nature of the Basin. One agreement on a water diversion schedule among three of the parties has been reached, partly as a result of this process. More comprehensive compromises have not yet been forged. Our experience, however, indicates that modeling success at the policymaking level depends more on the extent to which the policymakers understand the model than it does on model sophistication.     

Sustainable Water Resources Management in a Conflict Resolution Framework1

Abstract: A decision support system for sustainable water resources management in a water conflict resolution framework is developed to identify and evaluate a range of acceptable alternatives for the Geum River Basin in Korea and to facilitate strategies that will result in sustainable water resource management. Working with stakeholders in a “shared vision modeling” framework, sustainable management strategies are created to illustrate system tradeoffs as well as long‐term system planning. A multi‐criterion decision‐making (MCDM) approach using subjective scales is utilized to evaluate the complex water resource allocation and management tradeoffs between stakeholders and system objectives. The procedures used in this study include the development of a “shared vision model,” a simulated decision‐making support system (as a tool for sustainable water management strategies associated with water conflicts, management options, and planning criteria), and the application of MCDM techniques for evaluating alternatives provided by the model. The research results demonstrate the utility of the sustainable water resource management model in aid of MCDM techniques in facilitating flexibility during initial stages of alternative identification and evaluation in a basin suffering from severe water conflicts.     

FISH AND WILDLIFE ENHANCEMENT THROUGH WATER RESOURCES DEVELOPMENT1

.Fish and wildlife enhancement through water resources development implies fish and wildlife will be enhanced or benefit directly from such development. As a matter of practicality, the opposite may be the case in that wildlife lands of prime value and stream fisheries are often lost or severely altered as a result of reservoir construction or stream channelization. Additionally, estuarine fish and wildlife can also suffer from water resources development due to reductions in volume of fresh waters reaching the estuaries and adjacent marshes. In some instances waterfowl habitat can be created by reservoir construction and with good planning waterfowl habitat and use may be enhanced. To offset losses of thousands of acres of wildlife habitat when a river system is to be totally harnessed, planners could set aside sufficiently large natural areas dedicated for use by wildlife. This, however, would be replacement rather than enhancement. Reservoir fisheries can be enhanced with good planning to include timber clearing, shoreline clearing, boat road clearing, variable level drawoff devices and tailrace escapement channels. To sum up, it is possible for some species offish and wildlife to be enhanced through water resources development but only at the expense of others, and then only through careful and integrated planning.     

A comprehensive set of resource use indicators from the micro to the macro level

Many of today's most urgent environmental problems arise from increasing volumes of worldwide production and consumption and the associated use of natural resources, including renewable and non-renewable raw materials, energy, water and land. Solid indicators to measure different dimensions of anthropogenic resource use are essential for designing appropriate policy measures for a sustainable management of these resources. Based on a brief review of the current state of the art of resource use indicators, this paper suggests a new set of complementary resource use indicators, combining existing measures for resource use. The suggested indicator set covers the core resource input categories of materials, water and land area and includes the output category of greenhouse gas emissions. This set can be applied consistently from the micro level of products and companies up to the macro level of countries and world regions. All suggested indicators take a life-cycle wide perspective on production and consumption activities. This set of indicators deals with the issue of the overall scale of the human production and consumption system. It can be regarded as the general indicator framework, based on which more specific indicators, for example, on different environmental impacts related to natural resource use, can be calculated.     

实施最严格的野生动物保护:中国现状与改革方向

随着全球工业化和城市化的快速发展,野生动物及其栖息地保护面临着前所未有的挑战。本文识别了我国的野生动物保护存在的主要问题:(1)现行《野生动物保护法》对野生动物保护范围界定过窄,资源利用主导思维干扰了野生动物保护,缺乏对生态系统与生物安全的足够重视。(2)由于现行野生动物保护立法、执法和管理制度不健全甚至缺失,导致野生动物驯养繁殖交易市场长期混乱,甚至成为非法野生动物交易的"洗白工具"。(3)社会公众群体尊重和保护野生动物意识淡薄,全民参与和监督举报机制不健全。本文认为,我国应该实施最严格的野生动物保护制度,实现人与野生动物平等、文明、和谐相处,建议:(1)树立尊重野生动物物种生存权、人与野生动物文明和谐相处的理念,摒弃野生动物资源利用观,重构人与野生动物平等共存关系。(2)清晰界定野生动物法律定义,扩大野生动物保护范围,围绕捕猎、繁育、运输、储存、转让、食用等环节,全面、科学、精准地构建最严格的野生动物保护制度。(3)立足于全面保护野生动物,严格禁止滥食滥用野生动物和过度商业化利用,实行野生动物保护利用特许制度,并大幅提高标准严格控制交易和利用,建立职责清晰的执法监管和惩治体系。(4)建立最严格的野生动物保护公众参与和司法治理体系,实施野生动物非法贸易、猎杀的行政公益诉讼制度,引导公众建立爱护保护野生动物、不食不用野生动物的文明行为,最终实现人类社会与野生动物的文明和谐共处。     

Evaluation and valuation of wildlife resources

Issues of resource conservation and development are essentially about choice between alternative uses of land. Resource evaluation in rural planning has usually been based on assessments of land quality or capability in relation to a variety of alternative uses. In the case of wildlife, choices have to be made as to whether the wildlife resource is worth conserving at all and if so, which sites should be used. Considerable efforts have been made to rationalise, improve and make explicit the way in which choices are made, and this paper reviews the current position and draws attention to issues and developments which could lead to improvements in current practice.     

SOIL CONSERVATION PRACTICES AND WATER QUALITY: IS EROSION CONTROL THE ANSWER?1

ABSTRACT: This paper is a computer simulation analysis of an agricultural nonpoint pollution problem. Computer modeling is a universally applicable tool that can be used for establishing the linkages between and the quality of agricultural runoff in both surface and subsurface flow. The tradeoffs between the costs of soil conservation practices and water quality are reported, and the economic implications of such tradeoffs are discussed. Soil and nutrient losses resulting from crop production practices are analyzed using a field-scale computer simulation model (CREAMS). No-till planting, reduced tillage, and sod waterway systems are more cost effective than other practices for controlling soil and nutrient runoff losses. Nitrate leaching losses are increased slightly by most soil conservation practices. Terrace systems and permanent vegetative cover impose the greatest societal cost for water quality protection. Public cost sharing and tax incentives encourage farmers to adopt expensive structural practices, and policies are needed to get cost-effective practices implemented on critical acreage. Extensive treatment of land is necessary for agricultural best management practices (BMPs) to significantly improve water quality in areas that are intensively farmed.     

Assessing the Effects of Management Alternatives on Habitat Suitability in a Forested Landscape of Northeastern China

Forest management often has cumulative, long-lasting effects on wildlife habitat suitability and the effects may be impractical to evaluate using landscape-scale field experiments. To understand such effects, we linked a spatially explicit landscape disturbance and succession model (LANDIS) with habitat suitability index (HSI) models to assess the effects of management alternatives on habitat suitability in a forested landscape of northeastern China. LANDIS was applied to simulate future forest landscape changes under four management alternatives (no cutting, clearcutting, selective cutting I and II) over a 200-year horizon. The simulation outputs were linked with HSI models for three wildlife species, the red squirrel (Sciurus vulgaris), the red deer (Cervus elaphus) and the hazel grouse (Bonasa bonasia). These species are chosen because they represent numerous species that have distinct habitat requirements in our study area. We assessed their habitat suitability based on the mean HSI values, which is a measure of the average habitat quality. Our simulation results showed that no one management scenario was the best for all species and various forest management scenarios would lead to conflicting wildlife habitat outcomes. How to choose a scenario is dependent on the trade-off of economical, ecological and social goals. Our modeling effort could provide decision makers with relative comparisons among management scenarios from the perspective of biodiversity conservation. The general simulation results were expected based on our knowledge of forest management and habitat relationships of the species, which confirmed that the coupled modeling approach correctly simulated the assumed relationships between the wildlife, forest composition, age structure, and spatial configuration of habitat. However, several emergent results revealed the unexpected outcomes that a management scenario may lead to.     

Wildlife resource utilisation at Moremi Game Reserve and Khwai community area in the Okavango Delta, Botswana

This paper uses the concept of sustainable development to examine the utilisation of wildlife resources at Moremi Game Reserve (MGR) and Khwai community area (NG 18/19) in the Okavango Delta, Botswana. Using both secondary and primary data sources, results show that the establishment of MGR in 1963 led to the displacement of Khwai residents from their land; affected Basarwa's hunting and gathering economy; marked the beginning of resource conflicts between Khwai residents and wildlife managers; and, led to the development of negative attitudes of Khwai residents towards wildlife conservation. Since the late 1980s, a predominantly foreign owned tourism industry developed in and around MGR, however, Khwai residents derive insignificant benefits from it and hence resource conflicts increased. In an attempt to address problems of resource conflicts and promote sustainable wildlife utilisation, the Botswana Government adopted the Community-Based Natural Resource Management (CBNRM) programme, which started operating at Khwai village in 2000. The CBNRM programme promotes local participation in natural resource management and rural development through tourism. It is beginning to have benefits to Khwai residents such as income generation, employment opportunities and local participation in wildlife management. These benefits from CBNRM are thus having an impact in the development of positive attitudes of Khwai residents towards wildlife conservation and tourism development. This paper argues that if extended to MGR, CBNRM has the potential of minimising wildlife conflicts between Khwai residents and the wildlife-tourism sectors. This approach may in the process promote the sustainable wildlife use in and around MGR.     

Understanding Factors That Influence Stakeholder Trust of Natural Resource Science and Institutions

Building trust between resource users and natural resource institutions is essential when creating conservation policies that rely on stakeholders to be effective. Trust can enable the public and agencies to engage in cooperative behaviors toward shared goals and address shared problems. Despite the increasing attention that trust has received recently in the environmental management literature, the influence that individual cognitive and behavioral factors may play in influencing levels of trust in resource management institutions, and their associated scientific assessments, remains unclear. This paper uses the case of fisheries management in the northeast to explore the relationships between an individual’s knowledge of the resource, perceptions of resource health, and participatory experience on levels of trust. Using survey data collected from 244 avid recreational anglers in the Northeast U.S., we test these relationships using structural equation modeling. Results indicate that participation in fisheries management is associated with increased trust across all aspects of fisheries management. In addition, higher ratings of resource health by anglers are associated with higher levels of trust of state and regional institutions, but not federal institutions or scientific methods.     

Animal Welfare and Organic Aquaculture in Open Systems

The principles of organic farming espouse a holistic approach to agriculture that promotes sustainable and harmonious relationships amongst the natural environment, plants, and animals, as well as regard for animals’ physiological and behavioral needs. However, open aquaculture systems—both organic and conventional—present unresolved and significant challenges to the welfare of farmed and wild fish, as well as other wildlife, and to environmental integrity, due to water quality issues, escapes, parasites, predator control, and feed-source sustainability. Without addressing these issues, it is unlikely that open net-pen aquaculture production can be compatible with the principles inherent to organic farming.