Vulnerability of Fraser River sockeye salmon to climate change: A life cycle perspective using expert judgments

Fraser River sockeye salmon have been the basis for a major commercial fishery shared by Canada and the United States, and an important cultural foundation for many aboriginal groups; they are also of huge ecological significance throughout the Fraser Basin. The potential for altered aquatic habitat and temperature regimes due to climate change is an important concern for Fraser River sockeye salmon. This paper characterizes the vulnerability of Fraser River sockeye salmon to future climate change using an approach that is novel on three counts. First, previous efforts to assess the vulnerability of salmon to climate change have largely focused on only part of the life cycle, whereas we consider climate vulnerability at all stages in the life cycle. Second, we use the available scientific literature to provide a basis for structuring and eliciting judgments from fisheries science and management experts who research and manage these systems. Third, we consider prospects for mitigating the effects of climate change on sockeye salmon. Tests showed that participants’ judgments differentiated in statistically significant ways among questions that varied in terms of life stages, spawning regions and climate scenarios. The consensus among participants was that Fraser River sockeye are most vulnerable to climate change during the egg and returning adult stages of the life cycle. A high temperature scenario was seen as imposing the greatest risk on sockeye stocks, particularly those that migrate to the upper reaches of the Fraser River system and spawn earlier in the summer. The inability to alter water temperature and the highly constrained nature of sockeye management, with competing gear types and sequential fisheries over a long distance, suggest the potential to mitigate adverse effects is limited. Fraser River sockeye already demonstrate a great deal of adaptive capacity in utilizing heterogeneous habitats in different river sub-basins. This adaptability points to the potential value of policies to make stocks more resilient to uncertain futures.     

Planning for sustainable tourism in southern Pulau Banggi: an assessment of biophysical conditions and their implications for future tourism development

A priori assessments of a site's biophysical and socio-economic capacity for accommodating tourism are less common than tourism impact studies. A priori evaluations can provide a contextual understanding of ecological, economic and socio-cultural forces, which shape the prospects for sustainable tourism development at the host destination, and can avert adverse impacts of tourism. We conduct an a priori assessment of the biophysical environment of Pulau Banggi, in the Malaysian state of Sabah for sustainable tourism development. We characterise baseline conditions of the island's marine biodiversity, seasonality, and infrastructure. We then evaluate how existing biophysical conditions will influence options for sustainable tourism development. In particular, we suggest conditions, if there are any, which constitute a limit to future tourism development in terms of compatibility for recreation and resilience to visitor impacts. We find that the biggest constraint is the lack of adequate water and sanitation infrastructure. Blast fishing, although occurring less than once per hour, can potentially destroy the major attraction for tourists. We conclude that while Pulau Banggi possesses natural qualities that are attractive for ecotourism, financial and institutional support must be made available to provide facilities and services that will enable local participation in environmental protection and enhance prospects for future sustainable tourism.     

Transdisciplinary sustainability research beyond engagement models: Toward adventures in relevance

Transdisciplinary models of research are increasingly upheld as the gold standard of collaborative science to solve complex social and environmental problems, promising to ‘close the gap’ between knowledge and action, inject science with greater accountability, democratic participation, and include stakeholders as practitioners of research. Absent in transdisciplinary models are more ‘risky’ questions of relevance, subject positionality, and the lived encounters between researchers and stakeholders. Who are the ‘holders’ and who determines the ‘stakes’? This article examines how notions of roles, typologies, and effectiveness constrain relationships between researchers and stakeholders; and document the ways in which research teams, shot through with these tensions, in turn develop new roles, typologies, and markers of ‘success’. In drawing on recent philosophical scholarship on social science practices, we argue that relevance in transdisciplinary research cannot rest on typologies, logics, and templates of collaboration in which effectiveness is determined in advance. The growing business of team science and its predictive aspirations risk rendering transdisciplinary research irrelevant if its practitioners do not loosen the grip on realist perspectives on stakeholder roles, research outcomes, and metrics of success. Instead, we argue for the development of skills for paying attention to the categories, friction, and tensions that are provoked by collaborative interactions, discourses, and techniques with stakeholders. Environmental researchers must learn to be responsive to the durable existence of stakeholders and seek to develop the means to reveal what matters, and therefore is relevant, to them.     

Restructuring teacher education for sustainability: student involvement through a “strengths model”

In responding to the demand for major review of teacher education to meet the needs and challenges of the twenty-first century, the Faculty of Education at Griffith University in Queensland, Australia is in the throes of a major review of its primary teacher education program. This review is taking place in the midst of University wide debate on the nature and scope of Education for Sustainable Development (ESD). While consensus exists of the importance of ESD, debate continues regarding programs, policies, and practices.Education staff members feel strongly that new programs should encompass knowledge, issues, perspectives, skills, and values central to ESD, but remain uncertain about how this could best be achieved. The “strengths model” where every discipline and every staff member and student can contribute is being utilised by the working parties and is likely to be adopted as a means of ESD.To determine a benchmark for inclusion of components of ESD, and as one stage of including students in the decision-making process, a survey was conducted in February 2004 that sought to determine general environmental attitudes, specific practices and perceptions of a need to change.The survey indicated that a large portion of the students enrolled in preservice teacher education at this University were very concerned about environmental issues and felt that their preparation as teachers should include aspects of teaching about sustainability. The survey also indicated however, that the knowledge base regarding environmental issues was minimal and insight into the social, cultural and economic complexities of ESD was quite superficial. Students openly expressed a lack of confidence in their ability to make wise decisions or take appropriate action.This paper describes the context and strategies of the current restructure/reorientation of the preservice teacher program, highlighting the current and potential impacts of student involvement in the process.     

Male–male competition and alternative male mating tactics influence female behavior and fertility in Japanese medaka (Oryzias latipes)

Intense male–male competition driven by high male density during mating can result in the evolution of alternative mating tactics that increase male fertilization success. The effects of alternative male mating tactics on females can range from increased fertilization and genetic benefits to decreased fertilization and loss of paternal care. However, the influence of male competitive behavior and alternative mating tactics on female behavior and reproductive success has seldom been addressed. In this work, I investigated the occurrence of alternative male mating tactics and their potential influence on female behavior and fertilization success in Japanese medaka (Oryzias latipes). Groups of one, two, or four males competed for access to a female in a repeated-measures experiment. Male density had a significant influence on female reproductive output as a result of a change in competitive mode from contest to scramble competition that coincided with more disruption during mating when more than one male attempted to mate. By contrast, sneaking during mating was beneficial to males, as more than one male sired offspring in most spawnings involving sneaker males. These results suggest that there may be conflict between males and females over mating, such that females are detrimentally affected by the occurrence of alternative mating tactics, whereas males may benefit from sneak mating. The occurrence of conflict between the sexes can be related to ecological factors, such as male density, which cause behavioral change in both males and females.     

The importance of considering multiple interacting species for conservation of species at risk

Conservation of species at risk of extinction is complex and multifaceted. However, mitigation strategies are typically narrow in scope, an artifact of conservation research that is often limited to a single species or stressor. Knowledge of an entire community of strongly interacting species would greatly enhance the comprehensiveness and effectiveness of conservation decisions. We investigated how camera trapping and spatial count models, an extension of spatial-recapture models for unmarked populations, can accomplish this through a case study of threatened boreal woodland caribou (Rangifer tarandus caribou). Population declines in caribou are precipitous and well documented, but recovery strategies focus heavily on control of wolves (Canis lupus) and pay less attention to other known predators and apparent competitors. Obtaining necessary data on multispecies densities has been difficult. We used spatial count models to concurrently estimate densities of caribou, their predators (wolf, black bear [Ursus americanus], and coyote [Canis latrans]), and alternative prey (moose [Alces alces] and white-tailed deer [Odocoileus virginianus]) from a camera-trap array in a highly disturbed landscape within northern Alberta's Oil Sands Region. Median densities were 0.22 caribous (95% Bayesian credible interval [BCI] = 0.08–0.65), 0.77 wolves (95% BCI = 0.26–2.67), 2.39 moose (95% BCI = 0.56–7.00), 2.64 coyotes (95% BCI = 0.45–6.68), and 3.63 black bears (95% BCI = 1.25–8.52) per 100 km². (The white-tailed deer model did not converge.) Although wolf densities were higher than densities recommended for caribou conservation, we suggest the markedly higher black bear and coyote densities may be of greater concern, especially if government wolf control further releases these species. Caribou conservation with a singular focus on wolf control may leave caribou vulnerable to other predators. We recommend a broader focus on the interacting species within a community when conserving species.     

Numerical analysis of toxic cloud generation and dispersion: A case study of the ethylene oxide spill

The present study examined the accidental spill of ethylene oxide, and a sensitivity analysis of the corresponding consequences was conducted using computational fluid dynamics (CFD). A validation of the gas dispersion CFD model against the experimental data sets included in the model evaluation protocol (MEP) was performed. The effect of the variability of the wind velocity on the extension of the hazardous areas and pool evaporation characteristics was evaluated. Additionally, the mitigation effects of the dike walls surrounding a spill were discussed. CFD simulation results have shown that the mitigation effect of dike walls is determined by their influence on both gas dispersion and pool evaporation and depends strongly on wind velocity in terms of toxic impact distances.     

Comparing measured and modelled forest carbon stocks in high-boreal forests of harvest and natural-disturbance origin in Labrador, Canada

Understanding the effects of disturbance regimes on carbon (C) stocks and stock changes is a prerequisite to estimating forest C stocks and fluxes. Live-tree, dead-tree, woody debris (WD), stump, buried wood, organic layer, and mineral soil C stock data were collected from high-boreal black spruce (Picea mariana (Mill.) B.S.P.) stands of harvest and fire origin and compared to values predicted by the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3); the core model of Canada's National Forest Carbon Monitoring, Accounting and Reporting System. Data comparing the effect of natural and anthropogenic disturbance history on forest C stocks are limited, but needed to evaluate models such as the CBM-CFS3. Results showed that adjustments to the CBM-CFS3 volume-to-biomass conversion and partitioning parameters were required for the non-merchantable and branch C pools to accurately capture live-tree C stocks in the studied black spruce ecosystems. Accuracy of the CBM-CFS3 modelled estimates of dead organic matter and soil C pools was improved relative to regional default parameters by increased snag fall and >10 cm WD base decay rates. The model evaluation process also highlighted the importance of developing a bryophyte module to account for bryophyte C dynamics and the physical burial of woody debris by bryophytes. Modelled mineral soil C estimates were improved by applying a preliminary belowground slow C pool base decay rate optimized for the soil type of the studied sites, Humo-Ferric Podzols.     

Warming modifies trophic cascades and eutrophication in experimental freshwater communities

Climate warming is occurring in concert with other anthropogenic changes to ecosystems. However, it is unknown whether and how warming alters the importance of top-down vs. bottom-up control over community productivity and variability. We performed a 16-month factorial experimental manipulation of warming, nutrient enrichment, and predator presence in replicated freshwater pond mesocosms to test their independent and interactive impacts. Warming strengthened trophic cascades from fish to primary producers, and it decreased the impact of eutrophication on the mean and temporal variation of phytoplankton biomass. These impacts varied seasonally, with higher temperatures leading to stronger trophic cascades in winter and weaker algae blooms under eutrophication in summer. Our results suggest that higher temperatures may shift the control of primary production in freshwater ponds toward stronger top-down and weaker bottom-up effects. The dampened temporal variability of algal biomass under eutrophication at higher temperatures suggests that warming may stabilize some ecosystem processes.