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681.
Conservation subdivision design has been promoted as a way to protect ecologically sensitive areas while maintaining housing densities comparable to standard subdivisions, but many developers and planners question the appeal of conservation design to consumers. This study was conducted to compare economic aspects of conservation subdivision design to standard subdivision design in the midwestern United States. Three methods were used to determine the value homebuyers have for embedded conservation features in residential areas: transactional analyses (to indicate the value homebuyers have expressed for such features in the past); hedonic analyses (to determine the proportion of present value of homes attributable to such features); and contingent valuation (to examine willingness to pay according to homebuyers' preferred features, an indicator of potential future investment). Transactional analyses were based on assessment and transaction data for homes in three conservation-oriented subdivisions and three standard subdivisions in Cedar Rapids, Iowa, United States. Hedonic price models were also derived from assessment and transaction data. Contingent valuation analyses were based on a survey of residents in the same six subdivisions. Transactional data indicated higher 5-year appreciation rates for conservation versus standard subdivision design. Hedonic price models revealed that well-integrated conservation features (e.g. protected stream corridors) within subdivisions have a positive effect on home prices. Sixty-six percent of all respondents indicated willingness to pay for more embedded open space. Maximum willingness to pay was related to several factors including income, gender, desired level of open space, and concern about urban development. Overall, these results indicate that consumer demand and willingness to pay for conservation subdivision design are positive and should not be considered a barrier to implementation. 相似文献
682.
The capacity of duckweed to treat wastewater: ecological considerations for a sound design 总被引:1,自引:0,他引:1
Duckweed species are promising macrophytes for use in sustainable wastewater treatment due to their rapid growth, ease of harvest, and feed potential as a protein source. This paper reviews growth rates of different duckweed species on wastewater and ammonia toxicity to duckweed and summarizes insights into the mechanism of organic matter and nutrient removal. Results were gained from laboratory experiments in small, shallow, duckweed-covered semicontinuous batch systems. Growth rates on different types of wastewater vary considerably among different species. Ammonia is toxic for duckweed in both the ionized and un-ionized forms. Duckweed, however, can be used to treat wastewater containing very high total ammonia concentrations as long as certain pH levels are not exceeded. The degradation of organic material is enhanced by duckweed through both additional oxygen supply and additional surface for bacterial growth. The duckweed mat with attached bacteria and algae is, independent of the loading rates, responsible for three-quarters of the total nitrogen (N) and phosphorus (P) loss in very shallow systems. Based on our results we suggest that full-scale pilot plants with duckweed should be shallower than the range encountered in the literature. A harvesting schedule that allows doubling times of 2 to 3.5 d, maintenance of a full coverage, and plug flow conditions are recommended. 相似文献
683.
Jan C. van de Zande J. F. M. Huijsmans H. A. J. Porskamp J. M. G. P. Michielsen H. Stallinga H. J. Holterman A. de Jong 《The Environmentalist》2008,28(1):9-17
A summary is given of research within the field of application technology for crop protection products for the past 10 years
in The Netherlands. Results are presented for greenhouse, orchard, nursery tree and arable field spraying for the typical
Dutch situation. Research predominantly focussed on the quantification of spray deposition in crop canopy and the emissions
into the environment, especially spray drift. The risk of spray drift is related to defined distances and dimensions of the
surface water adjacent to a sprayed field. Spray deposition and spray drift research was setup in order to identify and quantify
drift-reducing technologies. Results are presented for cross-flow sprayers, tunnel sprayers and air-assisted field sprayers.
For field crop spraying with a boom sprayer the effect of nozzle type on spray deposition in crop canopy and spray drift is
highlighted both with a modelling approach as based on field experiments. The use of spray drift data in regulation is discussed.
A relation between spray deposition and biological efficacy is outlined for drift-reducing spray techniques. The effect of
spray drift-reducing technologies in combination with crop- and spray-free buffer zones is outlined. It is concluded that
spray technology plays an important role to minimise spray- and crop-free buffer zones, and to maintain biological efficacy
and acceptable levels of ecotoxicological risk in the surface water. 相似文献
684.
Richard Haynes Frans W. A. Brom Jan Elliott Peter Schaber 《Journal of Agricultural and Environmental Ethics》2000,13(1):1-5
Editorial Introduction
From the Editors 相似文献685.
686.
Marianne Lindström Maria Johansson Jan Herrmann Olle Johnsson 《Journal of Environmental Planning and Management》2006,49(4):495-513
Human actions towards land, freshwater and oceans have already caused biodiversity to decline. This study aims to investigate attitudes towards the conservation of biological biodiversity among different groups in a Swedish city, Kristianstad. An inquiry including statements measuring attitudes towards the conservation of habitats, animals and plants, to the biological diversity within selected local areas, to global and national areas, and to societal issues, was replied to by 271 persons. Deciduous forests, birds and wild flowers were given highest priority. An area categorized as wetland including lakeshore meadows with a rich bird life was prioritized as most important for conservation while a forest area was chosen as best for recreation. The experts gave lower priority to arable land, urban parks, domestic animals, agricultural and garden plants and to conifer forests compared to the other groups. Knowledge about what people in general value as important could facilitate the future planning of nature areas in the city of Kristianstad. 相似文献
687.
David J. Parsons David M. Graber James K. Agee Jan W. Van Wagtendonk 《Environmental management》1986,10(1):21-24
An evolving understanding of ecological processes, together with ambiguities in National Park Service policy, have led to multiple interpretations of the role of management in our large natural area National Parks. National Park Service management policies must be dynamic and responsive to changes in scientific knowledge and societal values. We propose that the principal aim of NPS resource management in natural areas is the unimpeded interaction of native ecosystem processes and structural elements. The case of the changing role of natural fire management is used as an example in developing this rationale. 相似文献
688.
Benjamin D. Trump Christy Foran Taylor Rycroft Matthew D. Wood Nirzwan Bandolin Mariana Cains Timothy Cary Fiona Crocker Nicholas A. Friedenberg Patrick Gurian Kerry Hamilton Jan Jeffrey Hoover Corey Meyer Kaytee Pokrzywinski Ryan Ritterson Paul Schulte Christopher Warner Edward Perkins Igor Linkov 《The Environmentalist》2018,38(4):517-527
Synthetic biology has the potential for a broad array of applications. However, realization of this potential is challenged by the paucity of relevant data for conventional risk assessment protocols, a limitation due to to the relative nascence of the field, as well as the poorly characterized and prioritized hazard, exposure, and dose–response considerations associated with the development and use of synthetic biology-derived organisms. Where quantitative risk assessment approaches are necessarily to fulfill regulatory requirements for review of products containing genetically modified organisms, this paper reviews one potential avenue for early-stage quantitative risk assessment for biosafety considerations of synthetic biology organism deployment into the environment. Building from discussion from a March 2018 US Army Engineer Research and Development Center workshop on developing such quantitative risk assessment for synthetic biology, this paper reviews the findings and discussion of workshop participants. This paper concludes that, while synthetic biology risk assessment and governance will continue to refine and develop in the coming years, a quantitative framework that builds from existing practice is one potentially beneficial option for risk assessors that must contend with the technology’s limited hazard characterization or exposure assessment considerations in the near term. 相似文献
689.
Jan M. Kooijman 《Environmental management》1993,17(5):575-586
The functions of packaging are derived from product requirements, thus for insight into the environmental effects of packaging
the actual combination of product and package has to be evaluated along the production and distribution system. This extension
to all related environmental aspects adds realism to the environmental analysis and provides guidance for design while preventing
a too detailed investigation of parts of the production system. This approach is contrary to current environmental studies
where packaging is always treated as an independent object, neglecting the more important environmental effects of the product
that are influenced by packaging.
The general analysis and quantification stages for this approach are described, and the currently available methods for the
assessment of environmental effects are reviewed. To limit the workload involved in an environmental assessment, a step-by-step
analysis and the use of feedback is recommended. First the dominant environmental effects of a particular product and its
production and distribution are estimated. Then, on the basis of these preliminary results, the appropriate system boundaries
are chosen and the need for further or more detailed environmental analysis is determined. For typical food and drink applications,
the effect of different system boundaries on the outcome of environmental assessments and the advantage of the step-by-step
analysis of the food supply system is shown. It appears that, depending on the consumer group, different advice for reduction
of environmental effects has to be given. Furthermore, because of interrelated environmental effects of the food supply system,
the continuing quest for more detailed and accurate analysis of the package components is not necessary for improved management
of the environmental effects of packaging. 相似文献
690.
Jan Jasiewicz 《Natural resources forum》1990,14(1):70-75
Energy cost for industry depends largely on the kind of energy used (or energy mix) and the in-country price of individual energy sources. The benefits of energy conservation measures may therefore not be uniform across industries and countries. A method is presented to evaluate the economics of energy conservation measures by industry. Thailand is used to illustrate how the method is applied. 相似文献