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1.
To combine the rational use of marine benthic resources and economic development of small-scale fishers, Chile passed legislation in 1991 establishing a comanagement policy that grants exclusive territorial user rights for fisheries (TURFs) to artisanal fisher organizations in well-defined inshore coastal areas, known as Management and Exploitation Areas for Benthic Resources (MEABRs). In general the policy has been proclaimed a management and economic success because benthic resource abundances have increased inside MEABRs in comparison with open-access areas. However, there is a lack of studies assessing the impact of this management policy on nontargeted subtidal species and community assemblages and the policy's implications for biodiversity and conservation. This study starts to fill this gap and links the allocation of TURFs for benthic resources with add-on conservation benefits for species that are not directly linked with the fishery policy. Comparative subtidal surveys inside vs. outside MEABRs were used to assess the effects of three MEABRs on managed targeted benthic species, biodiversity (species richness), and community assemblages in central Chile. Surveys focused exclusively on subtidal kelp forest habitats dominated by Lessonia trabeculata, spanning 4-12 m in depth and with similar levels of habitat complexity. The study comprised: (1) quantification of kelp forest complexity, (2) understory survey of sessile species, (3) quantification of conspicuous benthic macroinvertebrates, including those under management, and (4) quantification of reef-fish species inside the kelp habitat. Results showed population enhancement of target-managed invertebrates inside MEABRs. Moreover, reef-fish species were significantly more diverse and abundant inside MEABRs, and community assemblages of nontarget benthic invertebrates and reef fish were significantly different inside vs. outside MEABRs. The comanagement of inshore benthic resources in Chile, through MEABRs aims for the sustainability of invertebrate and algae stocks. However, our study shows that this management tool, which in practice restricts access to the entire management area, provides important conservation add-on effects for species that are not the focus of the management policies. Therefore, in Chile, the hundreds of already established MEABRs could represent an important ancillary network, which complements the biodiversity objectives of fully protected areas such as no-take marine protected areas or others.  相似文献   

2.
Why Economics Matters for Endangered Species Protection   总被引:3,自引:0,他引:3  
Abstract: We offer three reasons why economics matters more to species protection than many people think and what this implies for the ongoing debate over the reauthorization of the Endangered Species Act of 1973. Economics matters because (1) human behavior generally, and economic parameters in particular, help determine the degree of risk to a species; (2) in a world of scarce resources, the opportunity cost of species protection—the costs of reduced resources for other worthwhile causes—must be taken into account in decision making; and (3) economic incentives are critical in shaping human behavior, and consequently the recovery of species. Endangered species protection that explicitly addresses these basic principles can avoid wasting valuable resources that yield no gain in species protection.  相似文献   

3.
Abstract: The 1994 amendments to the U.S. Marine Mammal Protection Act required, for the first time, an assessment of the status of every marine mammal stock in the United States. We draw conclusions about the status of marine mammals from assessments of 153 stocks conducted to meet the requirements of these amendments. We found important regional differences in the status of stocks. Most stocks in the Atlantic and Pacific experience human-induced mortality (takes), primarily from gill-net fisheries. The proportion of stocks with takes was lower in the Gulf of Mexico and Hawaii, areas with few gill-net fisheries. Estimated takes exceeded removal limits for 29% of stocks in the Atlantic, 14% in the Pacific, 8% in Alaska, 7% in the Gulf of Mexico, and 0% in Hawaii. Twenty-eight stocks are listed as threatened or endangered under the U.S. Endangered Species Act. Most, but not all, baleen whale stocks are recovering after cessation of commercial harvests. Many species of pelagic cetaceans, including beaked and sperm whales, are vulnerable to mortality in pelagic drift-net fisheries. Most pinniped stocks experience takes, but none of these takes exceeds removal limits, and all pinniped stocks on mainland coasts of the United States are increasing in abundance. Quantitative data on trends in abundance are available for few cetacean stocks, emphasizing the difficulty of monitoring trends in these species. These stock assessments have greatly advanced our understanding of the status of marine mammals in the United States, but information gaps remain, particularly regarding stock structure and possible mortality in unmonitored fisheries.  相似文献   

4.
In the management of natural resources, regulation often induces behavioral responses by resource users that ultimately undermine stated policy objectives. Examples of these unintended consequences have been associated with regulations ranging from the Endangered Species Act to laws governing clean air. In this paper we investigate an unintended behavioral response that can be triggered by conservation measures in multispecies fishery management, which leads to increased targeting of the species the conservation measures are meant to protect. Harvest is subject to stochastic variation, with output partially determined by the probability of encountering species of interest, either due to targeting or avoidance. Given the right conditions, an intertemporal arbitrage opportunity arises due to the fact that by targeting a stock in the current period, the probability of encountering that stock in the next period, when announced conservation measures are implemented, decreases. We present an empirical case study that supports the findings of the theoretical model. The results indicate that, by targeting so called weak stocks, some New England fishermen are willing to trade off increased costs today for increased expected profits in the future. To prevent the potentially harmful effects of this behavioral response, a manager may adopt precautionary provisions at the time a quota reduction is announced, or alternatively allow the industry to bank part of its current season's quota in order to alleviate the consequences of the reduction in the ensuing period. These results highlight the challenge of developing effective conservation strategies.  相似文献   

5.
The U.S. Endangered Species Act grants protection to species, subspecies, and "distinct population segments" of vertebrate species. Historically, Congress included distinct population segments into endangered species legislation to enable the U.S. Fish and Wildlife Service to implement a flexible and pragmatic approach in listing populations of vertebrate species. Recently, the U.S. Fish and Wildlife Service and the National Marine Fisheries Service have proposed a policy that would narrowly define distinct population segments as evolutionarily significant units based on morphological and genetic distinctiveness between populations. Historically, the power to list species or populations as distinct population segments has been used to tailor management practices to unique circumstances; grant varied levels of protection in different parts of a species' range; protect species from extinction in significant portions of their ranges as well as to protect populations that are unique evolutionary entities. A strict redefinition of distinct population segments as evolutionarily significant units will compromise management efforts because the role of demographic and behavioral data will be reduced. Furthermore, strictly cultural, economic, or geographic justifications for listing populations as threatened or endangered will be greatly curtailed.  相似文献   

6.
Recent publications have reaffirmed that the red wolf ( Canis rufus ) is a hybrid of the coyote and the gray wolf. Besides the implications these results will likely have for future conservation efforts and allotment of resources through the Endangered Species Act for recovery of the red wolf, it is likely that broader consequences will be felt throughout the conservation community as species come under the scrutiny of a more powerful means of taxonomic identification. As molecular technology is refined in its ability to resolve taxonomic histories and uncertainties, it is likely that hybridization event(s) will be recognized in more species. This may be of particular importance for large carnivores, whose small population sizes make them susceptible to hybridization episodes with closely related, sympatric species. Because of negative perceptions, powerful antipredator advocates, conservation and resource constraints, and an enigmatic hybrid policy within the Endangered Species Act, how red-wolf taxonomy is decided by the U.S. Fish and Wildlife Service may affect the future of large carnivores in general.  相似文献   

7.
An important element of resource management and conservation is an understanding of the tradeoffs between marketed products, such as timber, and measures of environmental quality, such as biodiversity. In this paper, we develop an integrated economic-ecological spatial optimization model that we then apply to evaluate alternate forest policies on a 560,000 km2 study region of managed boreal forest in Alberta and British Columbia, Canada. The integrated model incorporates dynamic forest sector harvesting, current levels of oil and gas sector development, coarse-filter or habitat-based old forest indicators, a set of empirical forest bird abundance models, and statistical models of the natural and current fire regimes. Using our integrated model, economic tradeoff curves, or production possibility frontiers, are developed to illustrate the cost of achieving coarse-filter targets by a set time (50 years) within a 100-year time horizon. We found levels of ecological indicators and economic returns from the timber industry could both be increased if spatial constraints imposed by the current policy environment were relaxed; other factors being equal, this implies current policy should be revised. We explore the production possibility frontier's relationship to the range of natural variation of old forest habitat, and show how this range can be used to guide choices of preferred locations along the frontier. We also show that coarse-filter constraints on the abundance of certain habitat elements are sufficient to satisfy some fine-filter objectives, expressed as the predicted abundances of various species of songbirds.  相似文献   

8.
Accounting for Uncertainty in Making Species Protection Decisions   总被引:1,自引:0,他引:1  
Abstract:  Uncertainty gives rise to two decision errors in implementing the U.S. Endangered Species Act: listing species that are not in danger of extinction and delisting species that are in danger of extinction. I evaluated four methods (minimum standard, precautionary principle, minimax regret criterion, adaptive management) for deciding whether to list or delist a species when there is uncertainty about how those decisions are likely to influence survival of the species. A safe minimum standard criterion preserves some minimum amount or safe standard (population) of a species unless maintaining that amount generates unacceptable social cost. The precautionary principle favors not delisting a species when there is insufficient evidence on the efficacy of state management plans for protecting them. A minimax regret criterion selects the delisting decision that minimizes the maximum loss likely to occur under alternative ecosystem states. When the cost of making a correct decision is less than the cost of making an incorrect decision, the minimax regret criteria indicates that delisting is the optimal decision. Active adaptive management employs statistically valid experiments to test hypotheses about the likely impacts of delisting decisions. Safe minimum standard and minimax regret criterion are not compatible with the U.S. Endangered Species Act. The precautionary principle comes closest to describing how federal agencies make delisting decisions. Active adaptive management is scientifically superior to the other methods but is costly and time consuming and may not be compatible with the U.S. National Environmental Policy Act.  相似文献   

9.
In the absence of complete control in a regulated industry, effective management requires prediction of firms' behavioral responses to public policy. This paper develops a discrete choice model of supply response under uncertainty and applies it to fishery choice problems of New England fishing firms. While fishermen demonstrate a bias towards remaining within the same fishery, sufficient incentives, in terms of changes in expected returns and risk, are shown to elicit response. Due to extreme uncertainty concerning population dynamics of fish stocks, a satisficing approach to management, facilitated by this type of modelling, may be more appropriate than bioeconomic optimization.  相似文献   

10.
Abstract: Law plays an important role in shaping land management decisions. The success of efforts to conserve biodiversity thus depends to a large degree on how well scientific knowledge is translated into public policy. Unfortunately, the Endangered Species Act, the United States's strongest legal tool for conserving bidodiversity, contains serious biological flaws. The statute itself, as well us agency regulations and policies that implement the law include provisions that fail to account accurately for important biological concepts such us ecosystem conservation, patch dynamics, and the probabilistic nature of stochastic threats to a species' persistence. Moreover, the procedures of federal agencies charged with implementing the Endangered Species Act in some cases make it difficult for interested outside reviewers to evaluate the agencies' scientific findings and methodology. However, the Endangered Species Act also gives interested individuals and groups several opportunities to provide input into the process of managing threatened and endangered species. Conservation biologists should practice focused advocacy by taking advantage of such opportunities to steer law in a more biologically sound direction.  相似文献   

11.
The goal of ecosystem-based management (EBM) is to support a sustainable and holistic multisectored management approach, and is recognized in a number of international policy frameworks. However, it remains unknown how these goals should be linked to assessments and management plans for marine fauna, such as mammals and fish stocks. It appears particularly challenging to carry out trade-off analyses of various ocean uses without a framework that integrates knowledge of environmental, social, and economic benefits derived from nonstationary marine fauna. We argue this gap can be filled by applying a version of the ecosystem-service approach at the population level of marine fauna. To advance this idea, we used marine mammals as a case study to demonstrate what indicators could operationalize relevant assessments and deliver an evidence base for the presence of ecosystem services and disservices derived from marine mammals. We found indicators covering common ecosystem service categories feasible to apply; examples of indicator data are already available in the literature for several populations. We encourage further exploration of this approach for application to marina fauna and biodiversity management, with the caveat that conceptual tensions related to the use of the ecosystem service concept itself needs to be addressed to ensure acceptance by relevant stakeholders.  相似文献   

12.
Economics of the fishery has focused on the wastefulness of common pool resource exploitation. Pure open access fisheries dissipate economic rents and degrade biological stocks. Biologically managed fisheries also dissipate rents but are thought to hold biological stocks at desired levels. We develop and estimate an empirical bioeconomic model of the Gulf of Mexico gag fishery that questions the presumptive success of biological management. Unlike previous bioeconomic life history studies, we provide a way to circumvent calibration problems by embedding our estimation routine directly in the dynamic bioeconomic model. We nest a standard biological management model that accounts for complex life history characteristics of the gag. Biological intuition suggests that a spawning season closure will reduce fishing pressure and increase stocks, and simulations of the biological management model confirm this finding. However, simulations of the empirical bioeconomic model suggest that these intended outcomes of the spawning closure do not materialize. The behavioral response to the closure appears to be so pronounced that it offsets the restriction in allowable fishing days. Our results indicate that failure to account for fishing behavior may play an important role in fishery management failures.  相似文献   

13.
Historically, all capture fisheries have proven hard to manage; internationally shared stocks face an additional impediment to effective management. Previous fisheries studies estimate gains from cooperation for particular species or locations, but evidence is lacking on the wider effect that international sharing has in relation to other variables that affect stock status. This paper is an attempt to shed a broader light on the effect of sharing by identifying whether shared fish stocks are systematically more exploited. I compile exploitation status, biological and economic data into a unique two-period panel of more than 200 fish stocks from around the globe with which I test the theoretical implications of sharing. The empirical results from ordered category estimation suggest that shared stocks are indeed more prone to overexploitation.  相似文献   

14.
This paper looks for positive spillovers from the legal protection of one species to the welfare of others and for evidence of economies of scope in the costs associated with protecting species under the Endangered Species Act. The analysis uses data on the intensity of interest-group comment activity in response to proposals to protect new species. The results suggest that these phenomena are significant, strengthening arguments that wildlife-protection policy should be shifted toward species groups or ecosystems. However, the findings are also consistent with diminishing public willingness-to-pay for protected species in a given area, a pattern which also has public-policy implications.  相似文献   

15.
In this study, China’s current macro-environmental policies as well as their implementation and management tools are analyzed. By using the basic economic methodology, detailed studies are conducted focusing on the implementation effect of contemporary China’s typical environmental policy of the total pollutant discharge quantity control type, and also the two types of environmental management tools are compared from the perspective of implementation costs and policy uncertainty. By introduction of distributed management tools into the implementation of environmental policies, market-oriented means and the methods of economic analysis are introduced into environmental policy decision-making mechanisms, which could afford a new method for changing the current relatively low efficiency of environmental policy, solving the problem of “government failure” in environmental policy implementation, and providing a new way to make environmental policy system more flexible and more efficient. It is of great practical significance to solve China's current structural, complex and accumulative environmental problems.  相似文献   

16.
A Critique of the Recovery of Greenback Cutthroat Trout   总被引:2,自引:0,他引:2  
Abstract: There are no examples of recovery of fish listed under the U.S. Endangered Species Act, but the number of federally threatened greenback cutthroat trout (  Oncorhynchus clarki stomias ) populations is approaching the delisting goal. We evaluated recovery of this subspecies in light of developing theory in conservation biology and with regard to recovery of other salmonids in the inland western United States. Four of the five criteria used to define populations that would count toward delisting appeared to underestimate the risk of extinction of those populations. Typically, recovery goals for numbers of greenback cutthroat trout populations were less stringent than those for other inland salmonids petitioned for listing or listed as threatened under the Endangered Species Act and were comparable to those for a federally endangered species. Before delisting is considered, we propose that historical populations be replicated in additional waters to protect genetic diversity and that existing populations be enlarged to reduce their vulnerability to demographic variation, to increase their access to refugia, and to permit reestablishment of mobile life histories. Existing stocks should also be evaluated to determine whether they represent distinct population segments.  相似文献   

17.
In the late 1960's unrest between the aggregate industry and residents of high production municipalities threatened the availability of aggregate resources. At the request of the aggregate industry, the Ontario Provincial Government examined the situation and in 1971 passed The Pits and Quarries Control Act. The intent of the Act was to regulate the operation of pits and quarries and provide for their rehabilitation.Four years later, in 1975, the inadequacies of the Act prompted the establishment of the Ontario Mineral Aggregate Working Party to examine the situation and suggest changes. Despite considerable improvements brought about by the Pits and Quarries Control Act, 1971, difficulties such as resource protection still existed. The Working Party was a new concept to the Ontario Ministry of Natural Resources because it was composed of representatives of all groups concerned with the mineral aggregate question—various government ministries, regional and municipal councillors and staff, industry and special interest groups. Secondly, the Working Party incorporated a public participation program into its policy recommendations.New legislation, to be known as The Aggregates Act, was given first reading in the Ontario Legislature on June 14, 1979 and is expected to be passed before the end of 1979. It will replace the present Pits and Quarries Control Act. Also, policy guidelines are being formulated to aid municipalities in the preparation of official plans and zoning by-laws in an effort to designate and protect mineral aggregate resources for the future.Rehabilitation of pits and quarries continues to be a high priority item, as evidenced by the research being undertaken and funded by the Province. Efforts are also continuing in resource inventory and in public education, in an effort to promote acceptance of the aggregate industry. The management of aggregate resources in Ontario has progressed substantially in the past ten years, but a sustained effort in management and control must continue.  相似文献   

18.
A Diverse and Endangered Aquatic Ecosystem of the Southeast United States   总被引:6,自引:0,他引:6  
We document the biodiversity and conservation status of an extraordinarily diverse and endangered ecosystem in the United States that has failed to attract the same attention as tropical ecosystems—the rivers and streams of Alabama and adjoining states. Relative to North America as a whole, Alabama is a highlight of aquatic diversity supporting 38% of native fresh water fishes, 43% of native freshwater gill-breathing snails, 60% of native mussels, and 52% of native freshwater turtles. Of these, 41%, 77%, 34%, and 22% of the fishes, snails, mussels, and turtles, respectively, are endemic to Alabama and an adjacent state. Like many tropical systems of developing nations, this fauna is in an imperiled state, with 10%, 65%, 69%, and 43% of Alabama's fishes, gill-breathing snails, mussels, and turtles, respectively, considered either extinct, endangered, threatened, or of special concern. Unlike tropical systems, however, little effort has been made to protect the taxa and their habitats. Only 40% of fishes, 1% of gill-breathing snails, 32% of mussels, and 20% of freshwater turtles are formally listed as either threatened or endangered via the U.S. Endangered Species Act of 1973; no critical habitat has been protected. Clearly, the biodiversity crisis in not limited to tropical systems of developing nations. Although the Endangered Species Act of 1973 helps to ensure a future of sustainable diversity, efforts must be made to hasten recognition, protection, and recovery of critical habitat, particularly for hotspots such as the aquatic systems of Alabama.  相似文献   

19.
An alternative derivation of the irreversibility concept, with an application to the preservation of endangered species, is presented in this paper. The analysis involves a standard intertemporal welfare maximization procedure and is interested in the allocation of land between the production of economic goods and the preservation of species. Conversion of habitat is assumed to be irreversible. It is shown that the existence of utility value for species stocks, combined with increasing severity of the irreversibility constraint implies less conversion of species habitat than would occur in the absence of irreversibility.  相似文献   

20.
The large quattities of marine phytoplankton passing through the cooling systems of two Southern California coastal power plants were found to be greatly reduced in numbers (41.7%) and in volume (33.7%). The biomass killed from June, 1972 to May, 1973 amounted to approximately 1,700 tons of organic carbon. Phytoplankton mortalities were most pronounced from October to December when intake waters of 17° to 20°C were subjected to temperature elevations of 9 to 11C°, and were lowest from January to March when cooler ambient temperatures prevailed. There was no apparent reduction in phytoplankton stocks when the intake water was cooler than 15°C. Surviving cells in 25° and 26.5°C effluent waters were growing three times faster than influent populations, which suggests that power-plant effects on phytoplankton stocks are often short-lived. However, entrainment effects appear very disruptive, in changing the structure of phytoplankton communities and in constantly reducing species diversity (H′). Passage through the condenser tubes affected algal species differentially, killing diatoms in greater numbers (45.7%) than dinoflagellates (32.8%), and reinforcing the dominance of the two major species, Asterionella japonica and Gonyaulax polyedra, that were the most tolerant. The severity of the impact appears to be controlled by two interacting factors: intake water-temperature and magnitude of temperature increase. On this basis, use by coastal power plants of deep-sea water for cooling is strongly advocated.  相似文献   

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