Nature-based marine tourism in the Gulf of California and Baja California Peninsula: Economic benefits and key species

Ecotourism can incentivize social and environmental benefits through marine conservation, in parallel with efforts to better manage fisheries, coastal development, and other human pressures. In Mexico's Gulf of California and Baja California Peninsula (GCBP), marine ecosystems support tourism activities in many communities, but to date there have been no region-wide studies to estimate their benefits or identify key species. Based on data collected in this study, each year nature-based marine tourism in the GCBP results in 896,000 visits, US$518 million in expenditures and at least 3,575 direct jobs from formal operations. In interviews with operators, over 40 species groups were named as important; sea lions, whale sharks, whales, and marlin were the highest ranked, highlighting the importance of ecosystem-wide health for nature-based tourism sustainability. Local employment and the ability to make economic and conservation goals compatible were noted by operators as significant opportunities provided by nature-based marine tourism; challenges included pollution and declines in ecosystem health, a lack of infrastructure, poor resource management policies, and high operating costs. As nature-based marine tourism expands, a wider transition to true ecotourism, a focus on equitable benefits and collaboration between stakeholders and a cross-scale and ecosystem approach to management will be vital for achieving potential sustainable social, ecological and economic benefits.     

Phaeomelanin- and carotenoid-based pigmentation reflect oxidative status in two populations of the yellow warbler (Setophaga petechia)

Carotenoid- and phaeomelanin-based sexual pigmentation may signal a capacity to maintain oxidative balance and viability. However, diverse empirical results leave the association between pigmentation and oxidative stress (OS) unclear. We assessed the hypothesis that population-specific levels of oxidative challenge, or strategies for managing OS, affect relationships between sexual pigmentation and OS. Specifically, intense oxidative challenge in migratory, temperate breeding birds might enhance correlations between pigmentation and OS relative to allied tropical breeders, since quality-based differences in OS may arise only under intense oxidative challenge. Alternatively, in temperate breeders with intense within-season reproductive effort, high-quality birds may invest in reproduction over oxidative balance, dampening negative correlations between pigmentation and OS. To assess these alternatives, we compared prenesting relationships between pigmentation and OS in a migratory, Californian population of yellow warblers (Setophaga petechia brewsteri) and in a resident, Mexican population (Setophaga petechia bryanti, “mangrove warblers”). Yellow warblers displayed higher OS than mangrove warblers. However, year of capture and sex had bigger influences on correlations between pigmentation and OS than population. Males with more intense melanin pigmentation had lower OS among mangrove warblers and yellow warblers captured in 2011, but not among yellow warblers captured in 2012. In females only, lower OS levels were associated with more colorful carotenoid pigmentation. Results suggest that both phaeomelanin- and carotenoid-based pigmentation have the potential to correlate with OS levels, but that the signaling potential of pigmentation may shift with inter-annual variation in environmental conditions and display sex-specific dynamics.     

Metacommunity organization of soil microorganisms depends on habitat defined by presence of Lobelia siphilitica plants

We tested regional-scale spatial patterns in soil microbial community composition for agreement with species sorting and dispersal limitation, two alternative mechanisms behind different models of metacommunity organization. Furthermore, we tested whether regional metacommunity organization depends on local habitat type. We sampled from sites across Ohio and West Virginia hosting populations of Lobelia siphilitica, and compared the metacommunity organization of soil microbial communities under L. siphilitica to those in adjacent areas at each site. In the absence of L. siphilitica, bacterial community composition across the region was consistent with species sorting. However, under L. siphilitica, bacterial community composition was consistent with dispersal limitation. Fungal community composition remained largely unexplained, although fungal communities under L. siphilitica were both significantly different in composition and less variable in composition than in adjacent areas. Our results show that communities in different local habitat types (e.g., in the presence or absence of a particular plant) may be structured on a regional scale by different processes, despite being separated by only centimeters at the local scale.     

Synergistic effects of metal nanoparticles and a phenolic uncoupler using microdroplet-based two-dimensional approach

A droplet-based microfluidic technique for testing multiple reagent concentrations is presented. We used this experimental approach to study combined effects of gold (AuNP) and silver nanoparticles (AgNP) with the phenolic uncoupler 2,4-dinitrophenol (DNP) with respect to the growth of Escherichia coli. In order to evaluate the toxicity of binary mixtures, we first encapsulated the E. coli cells and particle mixtures inside the microdroplets using PEEK (polyetherketone) modules. Two-dimensional concentration spaces with about 500 well separated droplets were addressed. We subsequently analyzed the cell growth, the viability and the autofluorescence intensity (metabolic activity) of the bacteria with a micro-flow-through fluorometer and photometer. Dose-dependent synergistic effects were found for the binary mixture of AgNPs and DNP, which indicated a stronger interaction in the mixture than it was expected from effect summation. For the binary mixture of DNP and AuNPs in non-toxic concentrations, we found only weak synergistic effects at low DNP concentrations. Furthermore, the non-toxic tested AuNPs causes effect summation in the binary mixture with the phenolic uncoupler. In general, we demonstrated the efficiency of a droplet-based microfluidic system for fast high-throughput screenings of binary and multiple mixtures. This work also confirmed the relevance of highly resolved droplet-based assays for the miniaturization of ecotoxicological aquatic test systems.     

Modelling of occupational respirable crystalline silica exposure for quantitative exposure assessment in community-based case-control studies

We describe an empirical model for exposure to respirable crystalline silica (RCS) to create a quantitative job-exposure matrix (JEM) for community-based studies. Personal measurements of exposure to RCS from Europe and Canada were obtained for exposure modelling. A mixed-effects model was elaborated, with region/country and job titles as random effect terms. The fixed effect terms included year of measurement, measurement strategy (representative or worst-case), sampling duration (minutes) and a priori exposure intensity rating for each job from an independently developed JEM (none, low, high). 23,640 personal RCS exposure measurements, covering a time period from 1976 to 2009, were available for modelling. The model indicated an overall downward time trend in RCS exposure levels of -6% per year. Exposure levels were higher in the UK and Canada, and lower in Northern Europe and Germany. Worst-case sampling was associated with higher reported exposure levels and an increase in sampling duration was associated with lower reported exposure levels. Highest predicted RCS exposure levels in the reference year (1998) were for chimney bricklayers (geometric mean 0.11 mg m(-3)), monument carvers and other stone cutters and carvers (0.10 mg m(-3)). The resulting model enables us to predict time-, job-, and region/country-specific exposure levels of RCS. These predictions will be used in the SYNERGY study, an ongoing pooled multinational community-based case-control study on lung cancer.     

Injury outcomes and costs for cross-median and median barrier crashes

Introduction

The objective of this research was to quantify the injury outcomes and develop reliable and comprehensive injury costs for cross-median crashes (CMC) and median barrier crashes (MBC).

Method

A three-step methodology was developed to quantify the crash costs for each crash severity and type. All CMC and MBC between 2001 and 2007 in Wisconsin were identified and used in this analysis. The Wisconsin CODES database provided comprehensive injury costs based on the injury types and severities suffered by participants in study crashes.

Results

As expected, multi-vehicle CMC result in more total injuries and more severe injuries than single-vehicle CMC. Injury costs for the same injury level on KABCO scale are different for different crash types. Injury costs for concrete MBC are 33% to 50% less than those of multi-vehicle CMC, while the injury costs of concrete MBC for lower severities (B and C) are similar to those of single-vehicle CMC for the same severities; but for incapacitating injuries the costs are 30% less. As expected, concrete MBC result in lower severities than CMC. The costs, by crash severity, vary significantly between different crash types. Concrete median barrier injury crashes are roughly 20% of multi-vehicle CMC costs and 50% of single-vehicle CMC costs.

Conclusions

Results indicate that using one set of crash costs for all crash types biases any evaluation. Therefore, it is recommended that crash-type-specific costs be used in applications such as development of median barrier warrant where specific types of crashes are considered (CMC and MBC).

Impact on industry

Using crash specific costs can lead to a more realistic benefit-cost analysis and enable better decision-making.     

Community acceptance of policy options for managing the maintenance of rainwater tanks

This research examined community acceptance of policy instruments that could be used to promote ongoing maintenance of domestic rainwater tank systems. Using an online survey of 533 tank owners in South East Queensland, Australia, the research investigated four sets of factors that influence policy acceptance: features of the policy, judgements of policy fairness and effectiveness, contextual framing, and individual attitudes and motivations towards tank maintenance. An experimental design incorporating choice modelling was employed. Results demonstrated that perceptions of policy fairness and effectiveness are important to acceptance. Policies that include enabling features associate with increased perceptions of effectiveness, and policies that use incentives are linked to increased perceptions of both fairness and effectiveness. Individual attitudes and motivations regarding tank maintenance were significant predictors of policy support. Perceptions of a person's own ability to undertake tank maintenance tasks were negative predictors of policy intervention, suggesting that people who believe they can carry out maintenance themselves may not see the need for a policy that encourages tank maintenance to exist. The findings are discussed in relation to issues of policy design.