Supporting multi-stakeholder environmental decisions

This paper examines how multiple criteria analysis (MCA) can be used to support multi-stakeholder environmental management decisions. It presents a study through which 48 stakeholders from environmental, primary production and community interest groups used MCA to prioritise 30 environmental management problems in the Mackay-Whitsunday region of Queensland, Australia. The MCA model, with procedures for aggregating multi-stakeholder output, was used to inform a final decision on the priority of the region's environmental management problems. The result was used in the region's environmental management plan as required under Australia's Natural Heritage Trust programme. The study shows how relatively simple MCA methods can help stakeholders make group decisions, even when they hold strongly conflicting preferences.     

基于Delphi法和最小判别的应急能力逐级评价模式研究

针对目前应急能力评价模式中没有充分考虑最差的关键性指标,而该指标往往又决定着应急工作的成败这一问题,设计基于Delphi法和最小判别的应急能力逐级评价模式。以突发事件应急管理周期为基础,建立应急能力评价的三级指标体系,首先通过Delphi法确定第三级指标的评判以及相应的权重;然后以第三级指标为基础计算第二级评价指标的评价结果;最后,应急能力的最终评判和第一级指标的评判分别由下级指标通过最小判别法确定。实证表明,该模式具有系统性、科学性和可操作性,它充分考虑了关键指标中的最差指标对应急能力的影响,既有利于应急部门充分重视应急管理的薄弱环节,又有利于逐级查找影响应急能力的具体因素。     

Agricultural causes of desertification risk in Minqin, China

This study uses statistical modeling techniques to develop a desertification risk index (RI) for Minqin County, Gansu Province, China. Twenty socio-economic factors were selected and compared with the RI results to explore the spatial and temporal variability of desertification risk in the study area and to identify possible local driving forces behind desertification risk. The explanatory factors were different in 1988, 1992 and 1997, possibly reflecting the role of temporal variation as a contributor to desertification. The average number of sheep per-household was found to be an important indicator of change in desertification risk, while changes in ridge crop planting area explained the distribution of the rate of change in desertification risk in 1988-1992. The results suggests that the RI was useful in expanding the understanding of spatial temporal desertification issues in Minqin County, as well as identifying a current set of agricultural activities related to desertification risk. Further, given the limited nature of consistent data and observations for the area, development of the RI also served to establish a baseline for future investigations into desertification change and the risks such change might pose for the region.     

环保产业投入产出评价模型

本文在GNP指标基础上提出了NCV指标 ,其主要作用是同时考察经济增长和环境代价。对环境代价的测量目前还没有一个完全可行的方法。对此 ,文章提出生态乘数概念和自然资源再生周期函数 ,旨在提供一个定量分析环境污染的思路。     

Trade-off between fitness components in males of the polygynous butterfly Callophrys xami (Lycaenidae): the effect of multiple mating on longevity

The differential costs of mating paid by males and females influence the nature and strength of sexual selection. In butterflies, males invest a relatively large amount of time and resources in each mating, but male survival costs of mating have not been demonstrated. I present the results of experiments designed to measure the effect of different aspects of mating on male longevity in the polygynous butterfly Callophrys xami. In experiment 1, I compared the longevity of pairs of males that produced similar amounts of spermatophore, but that mated at different rates, a different numbers of times, and that produced spermatophores at different rates, and found that the longevity of ”low-mating-rate” males was not different from that of ”high-mating-rate” males. In experiment 2, the longevity of virgin males was not significantly different from that of multiply mated males. In experiment 3, I used resource-limited males resulting from experimental food limitation of last-instar larvae; resource-limited virgin males lived significantly more days than resource-limited multiply mated males. Since ecological costs of mating (e.g., disease transmission, predation risk) were excluded in the experiment, diminished male longevity was a product of physiological costs of sexual interactions. These results suggest that the cost of ejaculate production is an important cause of longevity reduction when there are resource limitations; however, the role of other possible physiological costs of mating in longevity reduction is still unknown. Received: 21 March 2000 / Accepted: 26 August 2000     

Diagnostic variables as predictors of ecological risk

The state of an ecosystem may be represented by a multidemensional state vector,x. The goal of ecosystem management is to insure that the ecosystem remains within some setX of acceptable states, such thatx X. Since ecosystem management decisions must be based on limited knowledge, a small number of diagnostic variables must be found which accurately reflect ecosystem state. If the vector of diagnostic variables, , is found to be within a specified set , the state vectorx is predicted to be withinX. The selection and use of such diagnostic variables is examined in the context of an aquatic ecosystem simulation model. Techniques used in searching for diagnostic criteria include multiple linear regression, discriminant analysis, and visual inspection of graphical data displays. The adequacy of a diagnostic criterion as a predictor of ecological risk is demonstrated to be a function of the associated rates of type I and type II statistical errors. A simple cost-benefit analysis is undertaken to illustrate one approach for choosing an optimal balance between these error rates.     

Genetic algorithm optimisation of water consumption and wastewater network topology

Genetic algorithm (GA) optimisation applied to water systems with multiple contaminants and several contaminated sources is presented. This approach generates the overall optimal water network topology with respect to the minimum supply water usage, complying, in the same time, with all restrictions. An optimal water network could be viewed as an oriented graph, starting from unit operations which must not have contaminants at entrance (inlet contaminants-free unit operations), every next unit operation i receiving streams from the previous operations j only (j = 1, 2,…,i−1), and sending streams to the next operations j (j = i + 1, i + 2,…,N). The mathematical model describing the unit i is based upon total and contaminant species’ mass balances, together with the input and output constraints. Solving this optimisation problem is not trivial, since the unknowns' number, determines the number of equations. The GA optimisation uses each network's internal flow as a gene, assembling the topology into a chromosome. The restrictions, in terms of minimum and maximum allowable flows for each gene, are dealt with naturally, during the population generation, simply rejecting those genes outside their feasible domain. The individuals are interbred according to their frequency of selection, using the one-point crossover method, and then mutations are applied to randomly selected individuals. The objective function is the total supply water consumption, which should be minimised.     

Sperm competition and ejaculate investment in red squirrels (<Emphasis Type="Italic">Tamiasciurus hudsonicus</Emphasis>)

Sperm competition is widespread in mammals and occurs when ejaculates from two or more males compete within the female’s reproductive tract to fertilize the ova. Enlarged testes are associated with sperm competition because they produce sperm, but the accessory glands produce fluids and proteins that are also important for fertilization success. Sperm morphology can also have consequences for fertilization success because of its influence on sperm motility. Red squirrels engage in multiple mating, and thus sperm competition is likely. Here, we assess levels of multiple paternity in a natural population of red squirrels, test the prediction that testis size is correlated with size of the accessory glands and sperm morphometry, and test the prediction that ejaculate investment is condition-dependent. Five of six litters (83%) showed evidence of multiple paternity, indicating that sperm competition is likely to have occurred. Testis size was correlated with the size of all three accessory glands (prostate, seminal vesicle, epididymides), and there was a generally positive relationship between the size of the accessory glands and sperm length. Sperm morphology showed significant variation in size and shape among individual male squirrels. There was no evidence of condition dependence of testis size or the size of the accessory glands, but sperm midpiece length was negatively related to body condition. Further work should include determining the fitness consequence of variation in sperm morphometry, testis size, and accessory gland size, and determining the effects of variation in ejaculate investment on sperm motility.