Bayesian testing for trend in a power model for clustered binary data

Developmental toxicity studies are widely used to investigate the potential risk of environmental hazards. In dose–response experiments, subjects are randomly allocated to groups receiving various dose levels. Tests for trend are then often applied to assess possible dose effects. Recent techniques for risk assessment in this area are based on fitting dose–response models. The complexity of such studies implies a number of non-trivial challenges for model development and the construction of dose-related trend tests, including the hierarchical structure of the data, litter effects inducing extra variation, the functional form of the dose–response curve, the adverse event at dam or at fetus level, the inference paradigm, etc. The purpose of this paper is to propose a Bayesian trend test based on a non-linear power model for the dose effect and using an appropriate model for clustered binary data. Our work is motivated by the analysis of developmental toxicity studies, in which the offspring of exposed and control rodents are examined for defects. Simulations show the performance of the method over a number of samples generated under typical experimental conditions.     

Valuation of climate-change effects on Mediterranean shrublands.

In general, the socioeconomic analysis of natural systems does not enter into the realms of natural science. This paper, however, estimates the human-welfare effects of possible physicochemical and biological impacts of climate change on Mediterranean shrublands over the coming 50 years. The contingent choice method was applied to elicit the trade-offs in perceived values for three climate-sensitive attributes of shrubland (plant cover, fire risk, and soil erosion) and for the costs of programs designed to mitigate changes. Soil erosion was found to be the attribute of shrubland that most concerned the population, followed by fire risk and then plant cover. An increase of 1% in the shrubland area affected by erosion was estimated to cost each person on average 2.9 euros per year in terms of lost welfare, a figure that is equivalent in terms of perceptions of social welfare to an increase of 0.24% in the shrub area burned annually and a decrease of 3.19% in the area of plant cover. These trade-off values may help ecologists, policy makers, and land managers to take social preferences into account.     

Robust benchmark dose determination based on profile score methods

We investigate several methods commonly used to obtain a benchmark dose and show that those based on full likelihood or profile likelihood methods might have severe shortcomings. We propose two new profile likelihood-based approaches which overcome these problems. Another contribution is the extension of the benchmark dose determination to non full likelihood models, such as quasi-likelihood, generalized estimating equations, which are widely used in settings such as developmental toxicity where clustered data are encountered. This widening of the scope of application is possible by the use of (robust) score statistics. Benchmark dose methods are applied to a data set from a developmental toxicity study.     

Special section: advancing the role of cities in climate governance – promise,limits, politics

This special issue contributes to scholarly debates about the role of cities in global climate governance, reflecting on the promise, limits, and politics of cities as agents of change. It takes an empirically-informed approach drawing on multiple diverse geographical and political contexts. Overall, the special issue aims to stimulate reflection and debate about where understanding and practice needs improvement to advance the role of cities in global climate governance. Key questions that are addressed in the special issue include: To what extent do real world experiences confirm or disconfirm the high expectations of cities as agents and sites of change in addressing global climate change as expressed in urban climate governance literature? In what ways do internal political dynamics of cities enable or constrain urban climate governance? How is climate governance in cities enabled and constrained by interactions with broader governance levels? In what ways can climate governance in cities be advanced through critical attention to the previous issues?     

Adaptive Management and Climate Change Adaptation: Two Mutually Beneficial Areas of Practice

Adaptive management (AM) is a rigorous approach to implementing, monitoring, and evaluating actions, so as to learn and adjust those actions. Existing AM projects are at risk from climate change, and current AM guidance does not provide adequate methods to deal with this risk. Climate change adaptation (CCA) is an approach to plan and implement actions to reduce risks from climate variability and climate change, and to exploit beneficial opportunities. AM projects could be made more resilient to extreme climate events by applying the principles and procedures of CCA. To test this idea, we analyze the effects of extreme climatic events on five existing AM projects focused on ecosystem restoration and species recovery, in the Russian, Trinity, Okanagan, Platte, and Missouri River Basins. We examine these five case studies together to generate insights on how integrating CCA principles and practices into their design and implementation could improve their sustainability, despite significant technical and institutional challenges, particularly at larger scales. Although climate change brings substantial risks to AM projects, it may also provide opportunities, including creating new habitats, increasing the ability to quickly test flow‐habitat hypotheses, stimulating improvements in watershed management and water conservation, expanding the use of real‐time tools for flow management, and catalyzing creative application of CCA principles and procedures.     

A cognitive approach to the post-Soviet Central Asian pasture puzzle: new data from Kyrgyzstan

Regional Environmental Change - Despite internationally recognized definitions, there remains debate over what constitutes ‘actual’ degradation in various agro-pastoral contexts. This...     

Feeding ecology of three species of Astropecten (Asteroidea) coexisting on shallow sandy bottoms of the northwestern Mediterranean Sea

Predation and competition are important biotic interactions influencing populations and communities in marine soft sediments. Sea stars are ubiquitous predators with diverse diets that play functionally important roles in the benthos. In this study, we examined the diet and the ecological roles of three sympatric species of the genus Astropecten (A. aranciacus, A. irregularis pentacanthus and A. platyacanthus). The study was performed between March 2010 and February 2011 on the Maresme coast (northwestern Mediterranean Sea). Results showed that their main diet consisted on gastropods and bivalves, such as Glycymeris glycymeris, Callista chione, Gibbula guttadauri and Cyclope neritea. Food competition between species was avoided by partition of prey resources. Intraspecific differences in the dietary compositions between seasons were found, but not between size classes. Ontogenetic patterns of prey size consumption were recognized in the three species. A large diet overlap was detected between A. aranciacus and A. platyacanthus in winter, due to changes in prey availability. Nevertheless, the analysis of the infaunal community composition and stomach contents indicated that food selection was not associated with prey availability.     

The meaning of the National Environmental Policy Act within the U.S. Forest Service

We conducted a survey of 3321 Forest Service employees involved in compliance with the National Environmental Policy Act (NEPA) followed by five focus groups to investigate agency views of the purpose of agency NEPA processes and their appropriate measures of success. Results suggest the lack of a unified critical task for Forest Service NEPA processes and that employees' functions relevant to NEPA influence their views of its meaning. Compared to other agency personnel, members of interdisciplinary teams who carry out most day-to-day NEPA-related tasks placed greater emphasis on minimizing negative environmental and social impacts, satisfying multiple stakeholders and avoiding litigation and appeals. Line officers, who typically serve as the decision makers following NEPA processes, placed greatest emphasis on efficient implementation and least emphasis on minimizing impacts. Advisory personnel placed greatest emphasis on effective disclosure of analyses and decision-making. We discuss the structural origins of these differences as well as their implications.     

Understanding the effects of different social data on selecting priority conservation areas

Conservation success is contingent on assessing social and environmental factors so that cost‐effective implementation of strategies and actions can be placed in a broad social–ecological context. Until now, the focus has been on how to include spatially explicit social data in conservation planning, whereas the value of different kinds of social data has received limited attention. In a regional systematic conservation planning case study in Australia, we examined the spatial concurrence of a range of spatially explicit social values and land‐use preferences collected using a public participation geographic information system and biological data. We used Zonation to integrate the social data with the biological data in a series of spatial‐prioritization scenarios to determine the effect of the different types of social data on spatial prioritization compared with biological data alone. The type of social data (i.e., conservation opportunities or constraints) significantly affected spatial prioritization outcomes. The integration of social values and land‐use preferences under different scenarios was highly variable and generated spatial prioritizations 1.2–51% different from those based on biological data alone. The inclusion of conservation‐compatible values and preferences added relatively few new areas to conservation priorities, whereas including noncompatible economic values and development preferences as costs significantly changed conservation priority areas (48.2% and 47.4%, respectively). Based on our results, a multifaceted conservation prioritization approach that combines spatially explicit social data with biological data can help conservation planners identify the type of social data to collect for more effective and feasible conservation actions.