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31.
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
32.
Natalie A. Jones Pascal Perez Thomas G. Measham Gail J. Kelly Patrick d’Aquino Katherine A. Daniell Anne Dray Nils Ferrand 《Environmental management》2009,44(6):1180-1195
Participatory modeling is increasingly recognized as an effective way to assist collective decision-making processes in the
domain of natural resource management. This article introduces a framework for evaluating projects that have adopted a participatory
modeling approach. This evaluation framework—known as the “Protocol of Canberra”—was developed through a collaboration between
French and Australian researchers engaged in participatory modeling and evaluation research. The framework seeks to assess
the extent to which different participatory modeling initiatives not only modify perceptions among and interactions between
participants, but also contribute to collective decision-making. The article discusses the development of the framework and
it’s application to three case-studies, two from Australia and one from the Pacific Island of the Republic of Kiribati. The
article concludes with some comments for future use of the framework in a range of participatory modeling contexts. 相似文献
33.
Øystein Flagstad Per Ole Syvertsen Nils ChR. Stenseth § John E. Stacy † Ingrid Olsaker ‡ Knut H. Røed ‡ and Kjetill S. Jakobsen† 《Conservation biology》2000,14(1):254-264
Abstract: Swayne's hartebeest ( Alcelaphus buselaphus swaynei ) is an endangered antelope that survives in four or five relict populations in Ethiopia. We examined the two main populations (Senkele and Nechisar) for mitochondrial (D-loop) and nuclear (microsatellite) variability in order to measure levels of genetic variation within the subspecies and degree of differentiation between populations. For comparison, we examined samples from a large population of red hartebeest ( Alcelaphus buselaphus caama ). Both swaynei and caama exhibited high levels of variation. There was significant differentiation between the populations of swaynei at Senkele and Nechisar, and gene diversity in Nechisar, the smaller of the two populations, was significantly lower than that in Senkele. Many mitochondrial haplotypes and microsatellite alleles present at high frequencies among the Senkele individuals were missing in Nechisar, suggesting that the translocation of animals from Senkele undertaken in 1974 did not contribute notably to the gene pool in Nechisar. Subsamples taken from Senkele in 1988 and 1995 showed a significant change in allele frequencies, a change that probably can be attributed to a massive population decline during this period. We recommend that both populations be protected in situ to maintain as much as possible of the diversity that exists within the taxon and that a breeding program be established. In spite of the earlier unsuccessful attempt, we argue that translocation of animals for enhancement of population size as well as genetic variation in Nechisar should be considered. 相似文献
34.
Genetic Effects of Multiple Generations of Supportive Breeding 总被引:11,自引:0,他引:11
Abstract: The practice of supporting weak wild populations by capturing a fraction of the wild individuals, bringing them into captivity for reproduction, and releasing their offspring into the natural habitat to mix with wild ones is called supportive breeding and has been widely applied in the fields of conservation biology and fish and wildlife management. This procedure is intended to increase population size without introducing exogenous genes into the managed population. Previous work examining the genetic effects of a single generation of supportive breeding has shown that although a successful program increases the census population size, it may reduce the genetically effective population size and thereby induce excessive inbreeding and loss of genetic variation. We expand and generalize previous analyses of supportive breeding and consider the effects of multiple generations of supportive breeding on rates of inbreeding and genetic drift. We derived recurrence equations for the inbreeding coefficient and coancestry, and thereby equations for inbreeding and variance effective sizes, under three models for selecting captive breeders: at random, preferentially among those born in captivity, and preferentially among those born in the wild. Numerical examples indicate that supportive breeding, when carried out successfully over multiple generations, may increase not only the census but also the effective size of the supported population as a whole. If supportive breeding does not result in a substantial and continuous increase of the census size of the breeding population, however, it might be genetically harmful because of elevated rates of inbreeding and genetic drift. 相似文献
35.
Nils T. Hagen 《Marine Biology》2008,153(5):907-924
Strongylocentrotus droebachiensis is a well known omnivorous sea urchin with an unrivalled capacity to destroy North Atlantic kelp forests. S. pallidus is a lesser known, morphologically similar, and closely related species with no record of destructive grazing, despite its
larger lantern size. I quantify the lantern size of both species using bivariate allometric analysis, and test the hypothesis
that enlarged lantern size facilitates durophagy, the consumption of hard prey, by measuring the feeding capacity of urchins
with different lantern sizes when offered a hard-shelled prey, the blue mussel, Mytilus edulis. The results suggest that S. droebachiensis has a limited capacity for durophagous feeding irrespective of lantern size, whereas in S. pallidus the ability to exploit hard shelled prey is positively related to lantern size. This is apparently the first evidence of
a relationship between trophic morphology and diet in regular sea urchins. The hypothesis of systematic latitudinal variation
in the lantern size of S. pallidus is reappraised and rejected. S. droebachiensis had larger gonads than S. pallidus in field samples, confirming that its small lantern is not impeding nutrient acquisition in shallow habitats. 相似文献
36.
Duarte-Guardia Sandra Peri Pablo L. Amelung Wulf Sheil Douglas Laffan Shawn W. Borchard Nils Bird Michael I. Dieleman Wouter Pepper David A. Zutta Brian Jobbagy Esteban Silva Lucas C. R. Bonser Stephen P. Berhongaray Gonzalo Piñeiro Gervasio Martinez Maria-Jose Cowie Annette L. Ladd Brenton 《Mitigation and Adaptation Strategies for Global Change》2019,24(3):355-372
Mitigation and Adaptation Strategies for Global Change - Soils hold the largest pool of organic carbon (C) on Earth; yet, soil organic carbon (SOC) reservoirs are not well represented in climate... 相似文献
37.
本文回顾了东非和西印度洋的岛屿在海藻、软体动物、鱼类和甲壳类动物的沿海养殖经验和状况.在许多方面,这一地区的沿海水产养殖仍处于发展初期,迫切需要制定旨在提高收入,确保沿海居民对可担负的蛋白质的获得的发展战略. 相似文献
38.
The pH of south Swedish soils have decreased considerably during the last 15–35 years. The decrease has occurred throughout the soil profile, not only in the rhizosphere, and is particularly marked in the originally less acid soils. The pH decrease was accompanied by considerable losses of exchangeable Na, K, Mg and Ca, as well as of Zn and (in the originally less acid soils) of Mn. The changes can be prognosticated from the current relationship between soil pH and base saturation and from budget calculations based on lysimeter data. 相似文献
39.
40.
Behaviors that appear to be plastic may well be determined by environmental influences during development. Being able to produce a wide range of variants of one kind of behavior, e.g., a very short and a very long response time to a stimulus under different environmental conditions, can be described as behavioral plasticity. How such behavioral reaction norms develop for individuals is poorly understood, but several factors are likely to play a role. We investigated what factors may affect how the risk-taking behavior of the lesser wax moth, Achroia grisella, is shaped during ontogeny. We manipulated larval density to represent the potential intensity of future competition for females in a lek of males, determined adult moths’ reaction to predator signals, and tested for plasticity in the silence response, i.e., the acoustic evasion behavior of the moths during the experiments. While we found no effect of larval density on either the probability or the duration of the silence response, 11 % of the variance in duration could be explained by differences between families, and 30 % of the variance was the result of differences between individuals. We found evidence for habituation to the predator signal, clearly indicating that the silence response is a plastic-enough trait to be adjustable to the immediate environment. These results suggest that the degree to which individuals take risks in the context of acoustic signaling depends more on the immediate context and, possibly, genetic differentiation than it is a product of adaptive developmental plasticity. 相似文献