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11.
Abstract

A number of cities around the world are associated with very high levels of private motor car usage, and Auckland provides an example of one of these ‘hyperautomobile’ cities. There are many problems with this system of transportation and dependence on the private car, including environmental, social and city design dimensions. Though there is a clear aspiration to move towards reduced levels of car usage in the city's transport and spatial planning strategies, there are major difficulties in implementation terms. We develop and consider future scenarios to 2041 to reduce these levels of motorization, and subsequent transport CO2 emissions, with a much greater use of public transport, walking and cycling, urban planning, and low emission vehicles. The current implementability of such a ‘sustainable mobility’ future is however questioned in the current political and social context, and critically debated in terms of the available governance mechanisms and the limited attempts to shape the behaviour of the public. We conclude by calling for a reconsideration of the policy measures being considered, including the range and levels of application and investment; with a much wider framing of the transport planning remit, and carried out within a much stronger participatory framework for decision-making.  相似文献   
12.
The field of engineering is changing rapidly as the growing global population puts added demands on the earth's resources: engineering decisions must now account for limitations in materials and energy as well as the need to reduce discharges of wastes. This means educators must revise courses and curricula so engineering graduates are prepared for the new challenges as practicing engineers. The Center for Sustainable Engineering has been established to help faculty members accommodate such changes through workshops and new educational materials, including a free access website with peer-reviewed materials.  相似文献   
13.
Controlling invasive species is critical for conservation but can have unintended consequences for native species and divert resources away from other efforts. This dilemma occurs on a grand scale in the North American Great Lakes, where dams and culverts block tributary access to habitat of desirable fish species and are a lynchpin of long‐standing efforts to limit ecological damage inflicted by the invasive, parasitic sea lamprey (Petromyzon marinus). Habitat restoration and sea‐lamprey control create conflicting goals for managing aging infrastructure. We used optimization to minimize opportunity costs of habitat gains for 37 desirable migratory fishes that arose from restricting sea lamprey access (0–25% increase) when selecting barriers for removal under a limited budget (US$1–105 million). Imposing limits on sea lamprey habitat reduced gains in tributary access for desirable species by 15–50% relative to an unconstrained scenario. Additional investment to offset the effect of limiting sea‐lamprey access resulted in high opportunity costs for 30 of 37 species (e.g., an additional US$20–80 million for lake sturgeon [Acipenser fulvescens]) and often required ≥5% increase in sea‐lamprey access to identify barrier‐removal solutions adhering to the budget and limiting access. Narrowly distributed species exhibited the highest opportunity costs but benefited more at less cost when small increases in sea‐lamprey access were allowed. Our results illustrate the value of optimization in limiting opportunity costs when balancing invasion control against restoration benefits for diverse desirable species. Such trade‐off analyses are essential to the restoration of connectivity within fragmented rivers without unleashing invaders.  相似文献   
14.
15.
Federal and State agencies have recently advocated risk-based analysis as a mechanism for advancing regulatory reform and safety determination in marine systems. the present investigation promotes this objective through the development of risk-based environmental planning strategies for oil spill contingency plans. This alternative approach to contingency planning departs from conventional methodology by employing quantitative risk assessment methods to identify hazardous oil spill zones and sensitive environmental areas, Ro and Re respectively. the product of this conversion is referenced on a single “Risk” layer within a Geographic Information System (GIS) framework allowing coastal managers to evaluate natural resource data with associated elements of oil spill risk. As a new tool for coastal pollution management, risk-based environmental planning strategies have shown potential for evolving more efficient oil spill contingency plans.  相似文献   
16.

The open space conservation sub-division offers an alternative to large-lot residential sub-divisions often seen as the culprit when urban sprawl transforms rural landscapes. Homes are sited on somewhat smaller lots, preserving natural areas for the local residents who share ownership of these communal areas and assume responsibility for their management. The article focuses on the experiences of residents of 13 relatively new open space communities. The interviews revealed that most of the communities have already confronted conflicting values with respect to natural areas, low resident participation and challenges in accessing appropriate information. While the open space conservation design holds great promise as a tool for innovative approaches to managing residential growth, it also calls for ways to anticipate and assist communities in caring for their local environment. Recommendations are offered for planning professionals based upon the experience of these open space community residents.  相似文献   
17.
A survey of vernal, forest-understory herbs was conducted on 52 routes, 10 sample sites each, along the Susquehanna River and its major and minor tributaries in southeastern Pennsylvania and northeastern Maryland. Mature forest stands, as compared to younger successional stands, had a greater diversity and cover of native understory herbs and greater frequencies of K -selected species such as Trillium flexipes and Dicentra canadensis . Vernal herbs with a high fidelity to the river corridor were likely to be more mesic in habitat preference, to occupy a more limited range of habitats, and to be less tolerant to disturbance than species that are also common in adjacent upland areas. The best vernal wildflower sites, which are usually in mesic or floodplain forest, may also be the most vulnerable to species loss if the canopy is removed or the forest is otherwise disturbed. Disturbance-sensitive herbs have been nearly extirpated from the Susquehanna tributaries by very intensive human development. Preservation of an appropriate matrix of microhabitats, particularly along the main river and at the mouths of the creeks, is critical to protecting the vernal flora of the region.  相似文献   
18.
Summary Adult female whitespotted sawyers Monochamus scutellatus (Coleoptera: Cerambycidae) were placed on succeeding days with two males differing visibly in size. Females showed a significant preference for the larger of two males. The rate of oviposition was significantly higher when the female was paired with the larger male. Both the rate of movement by the paired female and her rate of indicating non-receptivity were significantly lower when the female was paired with the larger male. This species exhibits resource defense polygyny, and females appear to choose mates mainly on the basis of the quality of resources defended. This study suggests, however, that when resource quality is constant, females choose mates on the basis of their size.  相似文献   
19.
A series of studies was performed to develop an alternative to the U.S. Environmental Protection Agency's gold standard IM240 mass-based emission test. The new IM147 test was based on the second phase of the IM240 that consists of 147 sec of transient vehicle operation. Paired IM240/IM147 tests were conducted on vehicles ranging from 1981 to 1996 to determine IM147 cutpoints and excess emissions were identified. Additionally, an optimized test procedure was developed that combined possible triplicate IM147s with improved drive trace quality control, fast-pass, and retest methods. The optimized procedure was found to provide improved vehicle preconditioning with a relatively minor decrease in excess emissions identification. Resulting identification rates ranged from 96 to 100% for hydrocarbons (HC), 93-100% for CO, and 93-100% for NOx, depending on cutpoint selection, while false failures caused by lack of vehicle preconditioning were reduced to essentially zero. Significant vehicle throughput improvements were achieved through the development of software algorithms involving modal fast-pass and retest procedures. Modal drive trace variation limits also were developed to improve test accuracy. The combination of the algorithms reduced average IM147 test times by nearly 60%.  相似文献   
20.
Concerns about energy security and climate change have sparked legislators’ interest in reducing gasoline consumption by increasing corporate average fuel-economy (CAFE) standards. Using an empirically rich simulation model and cost estimates for anticipated fuel-economy technologies, we estimate annual costs of reducing long-run gasoline consumption by 10% via a 3.8 miles per gallon increase in the standards, and the potential cost savings from allowing manufacturers to buy and sell fuel-economy credits. Maximum gasoline savings would be realized only after all existing vehicles were replaced, or 14 years in our model. A gasoline tax would produce greater immediate savings by encouraging people to drive less, and eventually to choose more-fuel-efficient vehicles. We demonstrate the advantage of a tax by comparing the cost of the higher CAFE standards over the first 14 years against the cost of a gasoline tax that would save the same amount of gasoline over that time.  相似文献   
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