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1.
Land managers decide how to allocate resources among multiple threats that can be addressed through multiple possible actions. Additionally, these actions vary in feasibility, effectiveness, and cost. We sought to provide a way to optimize resource allocation to address multiple threats when multiple management options are available, including mutually exclusive options. Formulating the decision as a combinatorial optimization problem, our framework takes as inputs the expected impact and cost of each threat for each action (including do nothing) and for each overall budget identifies the optimal action to take for each threat. We compared the optimal solution to an easy to calculate greedy algorithm approximation and a variety of plausible ranking schemes. We applied the framework to management of multiple introduced plant species in Australian alpine areas. We developed a model of invasion to predict the expected impact in 50 years for each species-action combination that accounted for each species’ current invasion state (absent, localized, widespread); arrival probability; spread rate; impact, if present, of each species; and management effectiveness of each species-action combination. We found that the recommended action for a threat changed with budget; there was no single optimal management action for each species; and considering more than one candidate action can substantially increase the management plan's overall efficiency. The approximate solution (solution ranked by marginal cost-effectiveness) performed well when the budget matched the cost of the prioritized actions, indicating that this approach would be effective if the budget was set as part of the prioritization process. The ranking schemes varied in performance, and achieving a close to optimal solution was not guaranteed. Global sensitivity analysis revealed a threat's expected impact and, to a lesser extent, management effectiveness were the most influential parameters, emphasizing the need to focus research and monitoring efforts on their quantification.  相似文献   
2.
ABSTRACT

This paper analyzes the discursive struggle over the reach and containment of spectacle in environmental politics to provide (a) case study-based evidence of how, on one hand, transnationally shared environmental awareness and concern, emerging in part through spectacle, is translating into expectations of participation and demands for accountability, and (b) how this is already impacting the ways in which environmental politics is being understood and enacted locally, regionally and transnationally. Drawing on recent mediated debate over the Great Barrier Reef, it finds that while the transnational is clearly an ambition for environmental campaigners, and the perception that transnational publics are emerging is already impacting environmental politics, the potency of these publics and their capacity to meaningfully negotiate accountability is yet to be empirically confirmed. Nevertheless, measures to contain spectacle are providing a potency for a transnational public sphere, even if in reality it is still little more than a specter.  相似文献   
3.
The level of water demand for supplemental irrigation and the impact of such demand on water supplies were estimated, as a function of the price of corn (Zea Mays L.). The method of estimation was based on an economic analysis of irrigation practice which assumed constant irrigation costs, profit maximizing behavior on the part of irrigators, and which was deliberately structured to underestimate the level of irrigation water use. The analysis was applied to and used data from the Little Wabash basin in Illinois. No irrigation was predicted at a corn price below $3.50 per bushel. Between $3.50 and about $6.50 per bushel, irrigation was estimated to be profitable for a small region of the basin where acceptable groundwater was available. Above about $6.50 to $7.50, irrigation was found to be profitable in the remainder of the basin, where impoundment storage was required. The potential impact on the water resources of the basin is significant. For a corn price between $3.50 and about $6.50, the probability of a shortfall, defined as the event where the potential demand exceeds the supply, was estimated to be between 2 percent and 20 percent during the growing season. Above about $7.50, this probability was found to be about one-third. The development of policies to control withdrawals for irrigation and other uses is endorsed.  相似文献   
4.
Many objectives motivate ecological restoration, including improving vegetation condition, increasing the range and abundance of threatened species, and improving species richness and diversity. Although models have been used to examine the outcomes of ecological restoration, few researchers have attempted to develop models to account for multiple, potentially competing objectives. We developed a combined state‐and‐transition, species‐distribution model to predict the effects of restoration actions on vegetation condition and extent, bird diversity, and the distribution of several bird species in southeastern Australian woodlands. The actions reflected several management objectives. We then validated the models against an independent data set and investigated how the best management decision might change when objectives were valued differently. We also used model results to identify effective restoration options for vegetation and bird species under a constrained budget. In the examples we evaluated, no one action (improving vegetation condition and extent, increasing bird diversity, or increasing the probability of occurrence for threatened species) provided the best outcome across all objectives. In agricultural lands, the optimal management actions for promoting the occurrence of the Brown Treecreeper (Climacteris picumnus), an iconic threatened species, resulted in little improvement in the extent of the vegetation and a high probability of decreased vegetation condition. This result highlights that the best management action in any situation depends on how much the different objectives are valued. In our example scenario, no management or weed control were most likely to be the best management options to satisfy multiple restoration objectives. Our approach to exploring trade‐offs in management outcomes through integrated modeling and structured decision‐support approaches has wide application for situations in which trade‐offs exist between competing conservation objectives.  相似文献   
5.
Abstract

Sustainability has come to play a dominant discursive role in the UK planning system, particularly relating to urban regeneration. The purpose of this paper is to evaluate the role that sustainability plays in a major regeneration programme, known as Eastside, currently underway in Birmingham, the UK. That this £6 billion redevelopment is now widely talked about by such key players as Birmingham City Council and the Regional Development Agency, Advantage West Midlands, as having a central sustainability agenda points to the growing importance of the ideal of sustainability in planning and regeneration agendas. In this paper, we investigate in detail how and why sustainability has become part of the planning discourse for Eastside and critically evaluate what impact, if any, this is having on public policy decision-making.  相似文献   
6.
Summary This paper outlines the second phase of an ecotourism project undertaken in the Santa Elena community, in the Monteverde region of Costa Rica. The community originally established a rainforest reserve with the help of Youth Challenge International in an attempt to provide a wider economic base and employment for the area. The project has been successful in the first phase in that it is now drawing an annual income of US$40 000 and it employs guides and management from the local community. In terms of the underlying principles usually aligned with ecotourism it has been successful but it is now necessary to evaluate the impacts this project is having on the community. The second phase of the project was to assess the sociocultural impacts of ecotourism on that community and the paper outlines this phase.Stephen Wearing is a lecturer in the School of Leisure and Tourism Studies at the University of Technology, Sydney. He lectures and consults in the area of tourism and environmental planning, and parks and protected area management. His particular interest is in ecotourism projects with local communities and he has spent much of the last 4 years working on the Santa Elena Project. He is linked with Youth Challenge International and people interested in becoming involved or looking for assistance with community projects of this nature can contact him at the above address. Libby Larson recently graduated with a BA in Leisure Studies at the University of Technology, Sydney, focusing on social sciences in natural resource management. She has also worked in Costa Rica with Youth Challenge International and is particularly interested in ecotourism.  相似文献   
7.
Genetic diversity within species represents a fundamental yet underappreciated level of biodiversity. Because genetic diversity can indicate species resilience to changing climate, its measurement is relevant to many national and global conservation policy targets. Many studies produce large amounts of genome-scale genetic diversity data for wild populations, but most (87%) do not include the associated spatial and temporal metadata necessary for them to be reused in monitoring programs or for acknowledging the sovereignty of nations or Indigenous peoples. We undertook a distributed datathon to quantify the availability of these missing metadata and to test the hypothesis that their availability decays with time. We also worked to remediate missing metadata by extracting them from associated published papers, online repositories, and direct communication with authors. Starting with 848 candidate genomic data sets (reduced representation and whole genome) from the International Nucleotide Sequence Database Collaboration, we determined that 561 contained mostly samples from wild populations. We successfully restored spatiotemporal metadata for 78% of these 561 data sets (n = 440 data sets with data on 45,105 individuals from 762 species in 17 phyla). Examining papers and online repositories was much more fruitful than contacting 351 authors, who replied to our email requests 45% of the time. Overall, 23% of our email queries to authors unearthed useful metadata. The probability of retrieving spatiotemporal metadata declined significantly as age of the data set increased. There was a 13.5% yearly decrease in metadata associated with published papers or online repositories and up to a 22% yearly decrease in metadata that were only available from authors. This rapid decay in metadata availability, mirrored in studies of other types of biological data, should motivate swift updates to data-sharing policies and researcher practices to ensure that the valuable context provided by metadata is not lost to conservation science forever.  相似文献   
8.
In four modern trees, hydrogen and oxygen isotope ratios track the modern temperature records.In a 2000-yr sequence of a Japanese cedar, there are the same periodicities of variation of D/H and O18/O16 as have been found in O18/O16 in a Greenland ice well.The same periodicities are found in uranium and organic carbon concentrations versus depth in a sea core from the Santa Barbara Channel, and in carbon-14 variations in a sequence of Bristlecone pine from southern California.In a 2000-yr sequence of Japanese cedar and in a 1000-yr sequence of European oak D/H and O18/O16 are related to each other by a slope of 8, just as they are in world-wide precipitation.In a 72-yr sequence of Sequoia gigantea, measured year by year for its oxygen isotope ratios, the 10.5-yr cycle of sunspot numbers found, but not the 21-yr cycle of sunspot magnetism; this we believe indicates that the sun is affecting the earth's climate with non-magnetic particles, probably photons.All these phenomena are related to periodic changes in sea surface temperature caused by periodic changes in the sun.  相似文献   
9.
The behaviour of juvenile herring (Clupea harengus L.) feeding on Artemia sp. nauplii in both light and dark was recorded using an infra-red-sensitive television-recording technique. In the light, two modes of feeding were observed, particle biting and filtering, but in the dark only filtering was observed. Marked differences in swimming behaviour were seen between light and dark. In the light, the fish continued to school while feeding in both modes; in the dark, the school dispersed, the fish swam slower in tight circular paths and fed only by filtering. In the dark, filtering fish swam faster (0.11 m s-1) than non-filtering fish (0.07 m s-1). In the light, no difference in speed was measured between filtering and non-filtering fish (0.34 m s-1). Owing to the lower filtering speeds in the dark, the removal rate of nauplii from the water was much lower than in light, except in the highest prey concentrations. This suggests that if night-time filter-feeding takes place in the sea, it will be of importance only when exploiting dense patches of food.  相似文献   
10.
We devised a participatory modeling approach for setting management thresholds that show when management intervention is required to address undesirable ecosystem changes. This approach was designed to be used when management thresholds: must be set for environmental indicators in the face of multiple competing objectives; need to incorporate scientific understanding and value judgments; and will be set by participants with limited modeling experience. We applied our approach to a case study where management thresholds were set for a mat‐forming brown alga, Hormosira banksii, in a protected area management context. Participants, including management staff and scientists, were involved in a workshop to test the approach, and set management thresholds to address the threat of trampling by visitors to an intertidal rocky reef. The approach involved trading off the environmental objective, to maintain the condition of intertidal reef communities, with social and economic objectives to ensure management intervention was cost‐effective. Ecological scenarios, developed using scenario planning, were a key feature that provided the foundation for where to set management thresholds. The scenarios developed represented declines in percent cover of H. banksii that may occur under increased threatening processes. Participants defined 4 discrete management alternatives to address the threat of trampling and estimated the effect of these alternatives on the objectives under each ecological scenario. A weighted additive model was used to aggregate participants’ consequence estimates. Model outputs (decision scores) clearly expressed uncertainty, which can be considered by decision makers and used to inform where to set management thresholds. This approach encourages a proactive form of conservation, where management thresholds and associated actions are defined a priori for ecological indicators, rather than reacting to unexpected ecosystem changes in the future.  相似文献   
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