The theory for a general equilibrium ecosystem model that can include large number of interacting species is presented. Features include: (1) individual plants and animals are assumed to behave as if they are maximizing their net energy intake, (2) short- and long-run equilibriums are obtained, (3) species’ population adjustments depend on individual net energies. The theory is applied using simulations of an eight-species Alaskan marine ecosystem for which a “natural” equilibrium is calculated. Humans are introduced by adding a regulated open access fishery that harvests one of the species. Fishing impacts the fish population as well as the populations of other species, including Stellar sea lions, an endangered species. The sensitivity of fish and nonfish species populations to harvesting are calculated. 相似文献
Objective: The objective of this study was to leverage a state health department's operational data to allocate in-kind resources (children's car seats) to counties, with the proposition that need-based allocation could ultimately improve public health outcomes.
Methods: This study used a retrospective analysis of administrative data on car seats distributed to counties statewide by the Georgia Department of Public Health and development of a need-based allocation tool (presented as interactive supplemental digital content, adaptable to other types of in-kind public health resources) that relies on current county-level injury and sociodemographic data.
Results: Car seat allocation using public health data and a need-based formula resulted in substantially different recommended allocations to individual counties compared to historic distribution.
Conclusions: Results indicate that making an in-kind public health resource like car seats universally available results in a less equitable distribution of that resource compared to deliberate allocation according to public health need. Public health agencies can use local data to allocate in-kind resources consistent with health objectives; that is, in a manner offering the greatest potential health impact. Future analysis can determine whether the change to a more equitable allocation of resources is also more efficient, resulting in measurably improved public health outcomes. 相似文献
Trophy hunting can provide economic incentives to conserve wild species, but it can also involve risk when rare species are hunted. The anthropogenic Allee effect (AAE) is a conceptual model that seeks to explain how rarity may spread the seeds of further endangerment. The AAE model has increasingly been invoked in the context of trophy hunting, increasing concerns that such hunting may undermine rather than enhance conservation efforts. We question the appropriateness of uncritically applying the AAE model to trophy hunting for 4 reasons. First, the AAE assumes an open‐access resource, which is a poor characterization of most trophy‐hunting programs and obscures the potential for state, communal, or private‐property use rights to generate positive incentives for conservation. Second, study results that show the price of hunting increases as the rarity of the animal increases are insufficient to indicate the presence of AAE. Third, AAE ignores the existence of biological and behavioral factors operating in most trophy‐hunting contexts that tend to regulate the effect of hunting. We argue that site‐specific data, rather than aggregated hunting statistics, are required to demonstrate that patterns of unsustainable exploitation can be well explained by an AAE model. Instead, we suggest that conservation managers seeking to investigate and identify constraints that limit the potential conservation role of trophy hunting, should focus on the critical governance characteristics that shape the potential conservation role of trophy hunting, such as corruption, insecure property rights, and inadequate sharing of benefits with local people. Aplicación del Modelo Antropogénico del Efecto Allee sobre la Caza de Trofeos como una Herramienta de Conservación 相似文献
SUMMARY In many developing countries, the determination of a ranking of investments designed to improve and extend the road system is a commonplace prerequisite of planning for the transport sector as a whole and the road sub-sector within it. A major objective of determining investment priorities is to secure the greatest efficiency in the use of resources allocated to the sector and, for this reason, any system of assigning priorities must rely upon conventional investment appraisal techniques producing quantifiable measures of worth. Exercises of this kind, in which road investments are identified and ranked, are usually undertaken to produce a road sector investment plan. The implementation of such plans is, however, often compromised because of perceived deficiencies with a methodology which places undue reliance on investment appraisal and fails to properly address the issue of public interest and sustainability. This paper attempts to produce a pragmatic set of ground rules which, while mindful of the need to promote economic efficiency, allow for other factors to be embraced in a more holistic methodology. 相似文献