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771.
The importance of accounting for economic costs when making environmental‐management decisions subject to resource constraints has been increasingly recognized in recent years. In contrast, uncertainty associated with such costs has often been ignored. We developed a method, on the basis of economic theory, that accounts for the uncertainty in population‐management decisions. We considered the case where, rather than taking fixed values, model parameters are random variables that represent the situation when parameters are not precisely known. Hence, the outcome is not precisely known either. Instead of maximizing the expected outcome, we maximized the probability of obtaining an outcome above a threshold of acceptability. We derived explicit analytical expressions for the optimal allocation and its associated probability, as a function of the threshold of acceptability, where the model parameters were distributed according to normal and uniform distributions. To illustrate our approach we revisited a previous study that incorporated cost‐efficiency analyses in management decisions that were based on perturbation analyses of matrix population models. Incorporating derivations from this study into our framework, we extended the model to address potential uncertainties. We then applied these results to 2 case studies: management of a Koala (Phascolarctos cinereus) population and conservation of an olive ridley sea turtle (Lepidochelys olivacea) population. For low aspirations, that is, when the threshold of acceptability is relatively low, the optimal strategy was obtained by diversifying the allocation of funds. Conversely, for high aspirations, the budget was directed toward management actions with the highest potential effect on the population. The exact optimal allocation was sensitive to the choice of uncertainty model. Our results highlight the importance of accounting for uncertainty when making decisions and suggest that more effort should be placed on understanding the distributional characteristics of such uncertainty. Our approach provides a tool to improve decision making.  相似文献   
772.
Despite early successes, the ‘zero-carbon homes’ agenda in England is being wound down. Ecological modernisation theory, which focuses on the way in which political, economic, and social forces interact with one other in the provision of environmental goods and services, is used to explain this. Existing literature on zero-carbon homes is fragmented, with scholars focusing on a range of social, economic, or political explanations. Ecological modernisation theory reconciles these various strands to produce a nuanced explanation for this agenda’s evolution. An ambitious but poorly defined legislative approach placed a burden on house-builders to meet compliance costs associated with zero-carbon, but framing sustainability economistically also led to considerable uncertainty. The 2008 financial crisis, the politicisation of housing, and the election of a government with a deregulatory mandate influenced the resilience of the policy agenda as private-sector actors exploited the uncertainty and political will in order to evade their policy burdens.  相似文献   
773.
为了对矿井突水水源进行准确、高效的判别,综合考虑水化学特征,选取Ca~(2+),Mg~(2+),K~++Na~+,HCO-3,SO2-4,Cl~-和总硬度7个指标的质量浓度(mg/L)作为矿井突水水源的最初判别指标。利用粗糙集(RS)理论的属性约简来筛选水化学特征指标,用以作为水源识别的核心判别指标,建立基于RS的矿井突水水源识别的最小二乘支持向量机(LSSVM)模型。选用约简处理后的13组煤矿数据对模型进行训练,再用训练好的模型对另外12组突水数据进行水源判别,并与未进行属性约简的LSSVM模型及Fisher判别分析法、随机森林方法进行对比。结果表明,利用属性约简方法可以很好地排除原始数据中的冗余信息干扰,因而能有效判别矿井突水水源,使矿井突水水源模型的误判率降低至0;而且指标约简过程可以降低LSSVM运算的复杂度,也能够提高判别效率。  相似文献   
774.
The global whaling debate is one of the most well-known environmental disputes; despite the continued moratorium, both whaling and conflict continue. This endless discord has been criticised as deleterious to whale conservation and as imperialistic towards whaling communities. The history of the whaling debate is examined through the lens of cultural theory (CT). CT argues that there is productive potential in respectful interaction between different perspectives on an environmental issue. Using CT, modern whaling past and present is reconstructed, tracking how different actors have come to prominence, altering the nature of the policy landscape through their actions. Since the onset of modern whaling, whales and whaling practice have been conceived in narrow terms, depending on the dominance of particular actors on either side of the debate. Proposed solutions to the impasse are assessed according to the maxims of CT.  相似文献   
775.
Here we propose an integrated framework for modeling connectivity that can help ecologists, conservation planners and managers to identify patches that, more than others, contribute to uphold species dispersal and other ecological flows in a landscape context. We elaborate, extend and partly integrate recent network-based approaches for modeling and supporting the management of fragmented landscapes. In doing so, experimental patch removal techniques and network analytical approaches are merged into one integrated modeling framework for assessing the role of individual patches as connectivity providers. In particular, we focus the analyses on the habitat availability metrics PC and IIC and on the network metric Betweenness Centrality. The combination and extension of these metrics jointly assess both the immediate connectivity impacts of the loss of a particular patch and the resulting increased vulnerability of the network to subsequent disruptions. In using the framework to analyze the connectivity of two real landscapes in Madagascar and Catalonia (NE Spain), we suggest a procedure that can be used to rank individual habitat patches and show that the combined metrics reveal relevant and non-redundant information valuable to assert and quantify distinctive connectivity aspects of any given patch in the landscape. Hence, we argue that the proposed framework could facilitate more ecologically informed decision-making in managing fragmented landscapes. Finally, we discuss and highlight some of the advantages, limitations and key differences between the considered metrics.  相似文献   
776.
ABSTRACT

Different human societies shape landscapes differently. Anthroecology theory explains this long-term differential shaping of landscapes as the product of sociocultural niche construction (SNC): an evolutionary theory coupling social change with ecosystem engineering. The evolutionary mechanisms underpinning this theory cannot be tested without experimental approaches capable of reproducing emergent selection processes acting on the combined suite of cultural, material, and ecological inheritances that determine the adaptive fitness of human individuals, groups, and societies. Agent-based modeling, as a ‘generative social science’ tool, appears ideal for this. Here we propose an agent-based virtual laboratory (ABVL) approach to generating and testing basic hypotheses on SNC as a general mechanism capable of producing the broadly varied anthroecological forms and dynamics of human landscapes from prehistory to present. While major challenges must still be overcome, a prospective modeling framework specification, guiding questions, and illustrative examples demonstrate clear potential for an ABVL to test predictions of anthroecology theory through generative social simulation.  相似文献   
777.
区域生态学基本理论探索   总被引:5,自引:0,他引:5       下载免费PDF全文
高吉喜 《中国环境科学》2013,33(7):1252-1262
全球经济一体化、区域发展一体化,以及生态服务转移引发的区域生态问题越来越受到人们的关注,区域生态问题也直接影响到区域的可持续发展.因此,构建一门针对区域生态问题的系统学科成为当务之急.本文基于生态学、地理学、经济学及其它相关学科理论,尝试从学科发展角度探讨建立区域生态学学科理论框架.文章提出区域生态学是研究区域生态结构、过程、功能,以及区域间生态要素耦合和相互作用机理的学科,生态介质是区域生态的联系纽带和核心要素.根据生态系统构成要素和当前人类活动,影响区域的突出生态介质有水、风和资源,通过这3种介质,分别形成流域、风域和资源圈3大类型生态区域.区域生态学的主要研究范畴和要点有:区域生态结构、过程与功能、区域生态完整性和生态分异规律、区域生态演变规律及其驱动力、区域生态承载力和生态适宜性、区域生态联系和生态资产流转,以及区域生态补偿和环境利益共享机制.  相似文献   
778.
通过采用混合培养料试验、日立8810型氨基酸自动分析仪和原子吸收法测定氨基酸含量和砷含量以及灰色系统理论分析关联度,研究了硒镧复合作用下巴西蘑菇子实体氨基酸含量和砷含量的变化和关系,为栽培砷含量低的巴西蘑菇提供科学依据.各硒镧复合处理的关联度排序为:B4>B1>B2>B0>B3.其中B4处理关联度最大,为0.835 1,B2最小,为0.726 9,说明硒镧浓度对巴西蘑菇子实体各氨基酸含量与砷含量有一定影响.各氨基酸含量与重金属砷含量关联度顺序为:丙氨酸>酪氨酸>胱氨酸>苯丙氨酸>赖氨酸>组氨酸>天门冬氨酸>异亮氨酸>苏氨酸>缬草氨酸>亮氨酸>甘氨酸>脯氨酸>精氨酸>丝氨酸>谷氨酸>甲硫氨酸.其中丙氨酸含量与砷含量关联度最大,为0.856 6,说明硒镧复合作用下巴西蘑菇子实体中丙氨酸含量与重金属砷含量的关系最为密切;关联度最小的是甲硫氨酸.  相似文献   
779.
We investigated the effect of financial incentives on performance in a professional organization. Whereas agency theory treats tangible rewards such as money as a potentially powerful motivator for improving performance, the professional control perspective posits that the motivational effects of financial incentives will depend on the intended recipients attitudes toward the incentives relative to their professional values. The study setting was a large network of physician practices that adopted a financial incentive program to improve physician performance in the management of diabetic patients. Consistent with agency theory, performance did improve following the introduction of the incentive. However, consistent with the professional control perspective, physicians' psychologically based attitudes toward the incentive program regarding its impact on their own work autonomy and the importance of the performance goals moderated the effect of the incentive on performance. Study findings indicate that agency theory and professional control are complementary theoretical perspectives for understanding how professionals will respond to the imposition of performance‐related financial incentives. In terms of practice, pay‐for‐performance programs aimed at professional organizations should be designed to take into account the values and goals of an organization's professionals to maximize the effect of financial incentives on performance. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
780.
The current study considered, for the first time, compensatory decisions within the theory of planned behaviour (TPB) to explain why people use mobile phones while driving. The effects of age, gender, and mobile phone mode on respondents’ answering intentions and compensatory decisions were mainly examined. A series of questions were administered to 333 drivers (ages 25-59), which included (1) demographic measures, (2) scales that measured prior mobile use activities in both driving and ordinary contexts, (3) a question to measure drivers’ perceptions of the safety of hands-free phones, and (4) TPB measures, which measured answer intention and two compensatory behavioural decisions (i.e., reminding the caller that he/she is driving, limiting the length of a conversations (including perceived its limits)), along with predictive variables. Drivers reported a moderate likelihood of answering intention and a strong tendency to engage in the two compensatory behaviours. Answering intention and compensatory decisions, perceived behavioural control, perceived risk, and usage frequency were more dependent on mobile phone mode and age group than gender. The regression models explained 64% and 67% of the variance in answering intention in the handheld and hands-free scenario separately. Attitudes, subjective norms, perceived behavioural risk and control (PBRC), and prior answering behaviour emerged as common predictors. The predictive models explained 31% and 37% of the variance for perceived limits of a conversation length in handheld and hands-free scenarios, respectively. Answering intention and PBRC consistently predicted most of the variance (handheld: 28%; hands-free: 32%) for this compensatory perception limits. The theoretical and practical implications of these results are discussed.  相似文献   
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