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41.
We consider how ecosystem services can be incorporated into water infrastructure planning by studying the projected deepening of the Lower Weser river channel in Germany. We recalculate the project's benefit–cost ratio by integrating the monetary value of changes in different ecosystem services, as follows: (1) the restoration costs of a mitigation measure for a loss in fresh water supply for agricultural production in the estuary region, (2) the costs of a loss in habitat services, transferring the willingness to pay from a contingent valuation study to the area assessed in the environmental impact assessment, and (3) the benefits of emissions savings induced by more efficient shipping, taking a marginal abatement cost approach. We find that including monetary values for ecosystem service changes leads to a substantial drop in the benefit–cost ratio. On this basis, we argue for a reform of the standard cost–benefit analysis to facilitate more complete welfare assessments. 相似文献
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Introduction of alien species is a major threat to biological diversity. Although public attention typically focuses on the species level, guidelines from the Convention of Biological Diversity define alien species to include entities below species level. This inclusion recognizes that release of nonlocal populations of native species may also result in negative effects on biodiversity. In practice, little is known about the extent, degree of establishment, or the effects on natural gene pools of such releases. Existing information on the releases in Sweden shows that alien populations are spread to a great extent. The most commonly released species include brown trout, Atlantic salmon, Arctic char, common whitefish, Scots pine, Norway spruce, mallard duck, gray partridge, and pheasant. Although millions of forest trees, fish, and birds are released annually, poor documentation makes the geographic and genetic origin of these populations, as well as the sites where they have been released, largely unclear. We provide recommendations for urgently needed first steps relating to the risks and problems associated with release of alien populations. 相似文献
44.
应对不确定性:呼吁建立新的科学政策论坛 总被引:4,自引:1,他引:4
Ann Kinzig David starrett Kenneth Arrow Sara Aniyar Bert Bolin Partha Dasgupta Paul Ehrlich Carl Folke Michael Hanemann Geoff Heal Michael Hoel AnnMari Jansson Bengt-Owe Jansson Nils Kautsky Simon Levin Jane Lubchenco Karl-Gran Miler Stephen W.Pacala Stephen H.Schneider Domenico Siniscalco Brian Walker 《Ambio-人类环境杂志》2003,32(5):330-335
科学界和政策界具有不同的目标,这就自然导致了对构成某种变化或现象的"检验"标准的差异,以及用不同的方法去描述不确定性和风险的持性及传达不确定性和风险.这些差异可能损害科学家、决策者和公众之间的有效沟通,同时也限制了科学家所愿意研究的社会紧迫问题的类型.本文主要回顾了一系列处理不确定性问题的方法,阐述了当科学和政策不能很好协调时所可能引起的一些错误.并在此基础上,特别针对解决不确定性问题提出了一些具体建议,包括重构科学规范,建立由科学、政策两方面领导广泛参加的科学政策论坛. 相似文献
45.
Rocío A. Pozo Eric G. LeFlore A. Bradley Duthie Nils Bunnefeld Isabel L. Jones Jeroen Minderman O. Sarobidy Rakotonarivo Jeremy J. Cusack 《Conservation biology》2021,35(1):297-306
Conflicts between the interests of agriculture and wildlife conservation are a major threat to biodiversity and human well-being globally. Addressing such conflicts requires a thorough understanding of the impacts associated with living alongside protected wildlife. Despite this, most studies reporting on human–wildlife impacts and the strategies used to mitigate them focus on a single species, thus oversimplifying often complex systems of human–wildlife interactions. We sought to characterize the spatiotemporal patterns of impacts by multiple co-occurring species on agricultural livelihoods in the eastern Okavango Delta Panhandle in northern Botswana through the use of a database of 3264 wildlife-incident reports recorded from 2009 to 2015 by the Department of Wildlife and National Parks. Eight species (African elephants [Loxodonta africana], hippopotamuses [Hippopotamus amphibious], lions [Panthera leo], cheetah [Acinonyx jubatus], African wild dogs [Lycaon pictus], hyenas [Crocuta crocuta], leopards [Panthera pardus], and crocodiles [Crocodylus niloticus]) appeared on incident reports, of which 56.5% were attributed to elephants. Most species were associated with only 1 type of damage (i.e., either crop damage or livestock loss). Carnivores were primarily implicated in incident reports related to livestock loss, particularly toward the end of the dry season (May–October). In contrast, herbivores were associated with crop-loss incidents during the wet season (November–April). Our results illustrate how local communities can face distinct livelihood challenges from different species at different times of the year. Such a multispecies assessment has important implications for the design of conservation interventions aimed at addressing the costs of living with wildlife and thereby mitigation of the underlying conservation conflict. Our spatiotemporal, multispecies approach is widely applicable to other regions where sustainable and long-term solutions to conservation conflicts are needed for local communities and biodiversity. 相似文献
46.
Consumer's choice of food can influence the environment. In Sweden, in common with many other countries, consumers need to be given information so they can make environmentally informed shopping choices. However, what is the most advantageous dietary choice to lower greenhouse emissions? This study investigates the greenhouse gas emissions associated with food production for food consumed in Sweden annually. Specifically, this study compares greenhouse gas emissions associated with a nutritionally and environmentally sustainable diet with the average consumption of food in Sweden 1999. The study concludes that the change in energy use and greenhouse gas emission associated with this change of diet is negligible. Lowering greenhouse gas emissions by changing food production processes results in more profound changes than teaching consumers to make environmentally correct choices. There is a basic need for a reduction or a replacement of the use of fossil fuels to produce and distribute our food in order to reach any significant reduction in the emission of greenhouse gases. Swedish agricultural policy does not provide ways to reduce greenhouse gas emissions. In Sweden therefore there is an immediate need to design policy instruments with the primary aim of reducing the greenhouse effect. 相似文献
47.
Ecological limitations and appropriation of ecosystem support by shrimp farming in Colombia 总被引:4,自引:0,他引:4
Shrimp farming in mangrove areas has grown dramatically in Asia and Latin America over the past decade. As a result, demand
for resources required for farming, such as feed, seed, and clean water, has increased substantially. This study focuses on
semiintensive shrimp culture as practiced on the Caribbean coast of Colombia. We estimated the spatial ecosystem support that
is required to produce the food inputs, nursery areas, and clean water to the shrimp farms, as well as to process wastes.
We also made an estimate of the natural and human-made resources necessary to run a typical semiintensive shrimp farm. The
results show that a semiintensive shrimp farm needs a spatial ecosystem support—the ecological footprint—that is 35–190 times
larger than the surface area of the farm. A typical such shrimp farm appropriates about 295 J of ecological work for each
joule of edible shrimp protein produced. The corresponding figure for industrial energy is 40:1. More than 80% of the ecological
primary production required to feed the shrimps is derived from external ecosystems. In 1990 an area of 874–2300 km2 of mangrove was required to supply shrimp postlarvae to the farms in Colombia, corresponding to a total area equivalent to
about 20–50% of the country’s total mangrove area. The results were compared with similar estimates for other food production
systems, particularly aquacultural ones. The comparison indicates that shrimp farming ranks as one of the most resource-intensive
food production systems, characterizing it as an ecologically unsustainable throughput system. Based on the results, we discuss
local, national, and regional appropriation of ecological support by the semiintensive shrimp farms. Suggestions are made
for how shrimp farming could be transformed into a food production system that is less environmentally degrading and less
dependent on external support areas. 相似文献
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The effect of different ambient sulphide concentrations on the internal pH regime of Hediste (Nereis) diversicolor was studied under in vivo conditions using liquid membrane pH microelectrodes, a method which is new to marine sciences.
As a case study, the hypothesis was tested whether organisms exposed to ambient sulphidic conditions are able to lower their
internal pH which, in effect, would reduce sulphide influx into the animals and thus could represent an effective detoxification
mechanism. It was shown that a significant lowering of the internal pH occurred within only 20 min after adding sulphide.
This pH lowering appeared to be dependent on the external sulphide concentration of the ambient medium and showed a saturation
beyond a threshold level of about 130 μM. It is discussed whether this sulphide-induced pH drop is an active regulatory mechanism
and acts as an effective protection mechanism against sulphide during short-term exposures.
Received: 1 June 1999 / Accepted in revised form: 3 May 2000 相似文献