Uncertainty representation and propagation in quantified risk assessment using fuzzy sets

It is generally acknowledged that there are substantial uncertainties present in any analysis of risk. This paper provides a brief overview of the current techniques used for uncertainty analyses, and highlights their inappropriateness for practical use in the complete risk assessment process. The concept of fuzzy sets as a means for quantifying uncertainty is introduced and a case study demonstrates the application of this method to a simple consequence analysis where parameter uncertainty is considered. The results of this fuzzy analysis are compared with those of a more traditional probabilistic approach using a Monte Carlo simulation. This comparison demonstrates that the novel approach of fuzzy sets is a more appropriate technique due to its non-statistical nature and that the amount of computation required is substantially reduced compared to the traditional probabilistic approach. The versatility of fuzzy set theory suggests that this approach could also be used to quantify other types of uncertainty present in the risk assessment process, including model uncertainty and expert opinion.     

Are low infidelity rates in feral horses due to infanticide?

A growing number of studies conducted on diverse taxa have shown that extra-pair/group paternity is higher than what would be predicted from behavioral observations alone. While it may be beneficial for females to mate with multiple males, this often results in offspring not sired by the behavioral father, which could influence offspring survival, especially in social mammals. Feral horses (Equus caballus) maintain stable social relationships over several years, usually with one stallion defending a harem band of unrelated mares against other males. Sneak copulations by subordinate males have been observed and mares sometimes change bands, both of which can result in foals sired by males other than the dominant band stallion. We measured female fidelity in free-ranging feral horses in 23 bands, with 51 foals over four foaling seasons and tested offspring paternity against parental behaviors. We used 12 polymorphic microsatellite loci and the program CERVUS 2.0 to determine and exclude potential sires. The majority of mares remained in the band with the sire of their foal resulting in most foals being sired by the band stallion. Most foals that were not sired by the band stallion were born in the year after a round-up and we could not determine if they were the result of band changing or sneak copulations. Foals born into a band without their sire had lower survival rates and mothers were significantly more protective of foals not sired by the band stallion. These findings suggest that band stability increases the reproductive success of mares and support the importance of infanticide risk in equid social structure.     

Climate change and the cost of conserving species in Madagascar

We examined the cost of conserving species as climate changes. We used a Maxent species distribution model to predict the ranges from 2000 to 2080 of 74 plant species endemic to the forests of Madagascar under 3 climate scenarios. We set a conservation target of achieving 10,000 ha of forest cover for each species and calculated the cost of achieving this target under each scenario. We interviewed managers of projects to restore native forests and conducted a literature review to obtain the net present cost per hectare of management actions to maintain or establish forest cover. For each species, we added hectares of land from lowest to highest cost per additional year of forest cover until the conservation target was achieved throughout the time period. Climate change was predicted to reduce the size of species' ranges, the overlap between species' ranges and existing or planned protected areas, and the overlap between species' ranges and existing forest. As a result, climate change increased the cost of achieving the conservation target by necessitating successively more costly management actions: additional management within existing protected areas (US$0-60/ha); avoidance of forest degradation (i.e., loss of biomass) in community-managed areas ($160-576/ha); avoidance of deforestation in unprotected areas ($252-1069/ha); and establishment of forest on nonforested land within protected areas ($802-2710/ha), in community-managed areas ($962-3226/ha), and in unprotected areas ($1054-3719/ha). Our results suggest that although forest restoration may be required for the conservation of some species as climate changes, it is more cost-effective to maintain existing forest wherever possible.     

Landscape Assessment of the Degree of Protection of Alaska's Terrestrial Biodiversity

Abstract: We assessed the degree to which Alaskan lands reflect the state's biodiversity by dividing the entire state into four categories of land protection ranging from highly protected to minimally protected in terms of potential for future development. We then compared the percentage of each ecoregion and plant-cover type in each land protection class. We assumed that 12% protection represents an acceptable minimum and examined the percentage of site records of rare plants in protected and unprotected areas. Of 28 ecoregions in Alaska, 15 (63.4%) have <12% of their area in highly protected areas. Similarly, 11 of 21 vegetation-cover types (43.7%) have <12% protection. For 32 rare vascular plants, an average of 27% of records occur on highly protected lands. Seventy-five percent of the rare plants had <50% of their records from highly protected lands. Less than 1% of Alaska has been permanently altered by human activity. In contrast to the lower 48 states, time remains to plan development that preserves biodiversity while permitting an economically sustainable economy—if the effort is made now.     

The unequal distribution of occupational health and safety risks among immigrants to Canada compared to Canadian-born labour market participants: 1993–2005

ObjectivesTo examine the prevalence of occupational health and safety risk factors among immigrants to Canada compared to Canadian-born labour force participants.MethodsUsing data from Statistic Canada’s Survey of Labour and Income Dynamics, we examined the differential probabilities of six different occupational health and safety risks: non-membership in a union or collective bargaining agreement; employment in physically demanding occupations; employment in a workplace with less than 20 employees; regular shift work; irregular shift work; and having non-permanent employment. Our main independent variables were length of time in Canada, visible minority status, mother tongue, and location where highest level of education was attained. Models were adjusted for age, gender, education, marital status, province of residence, living in an urban or rural location, and industry group.ResultsOf the six occupational health and safety risks examined we found that our main independent variables describing aspects of immigration status were associated with five; the exception being irregular shift work. Adjustment for industry did not attenuate these relationships to a large extent.ConclusionsImmigrants to Canada are faced with many occupational health and safety risks compared to Canadian-born respondents. These risks may be heightened among immigrants as they may not have knowledge of workplace rights and protections or have problems communicating health and safety risks or concerns. The timely provision information on occupational health and safety to immigrants before they start working should be a priority as they integrate into the Canadian labour market.     

Suggested Guidelines for Use of Avian Species as Biomonitors

An animal’s suitability as a biomonitor of environmental change can be determined by biological, reproductive and ecological characteristics determined at the class, order and species level. The animal’s habitat where the research is to be performed and the form, function and structure of the environmental change being studied within that habitat also determines suitability. Non-threatened populations of large, non-migratory, long-lived, seasonally-breeding tertiary avian predators, whose dietary preferences are narrow and known, can be useful as monitors of environmental chemical contaminants. If chemicals are being monitored, a quantifiable endpoint effect must be demonstrated in the species, or a similar species under experimental laboratory conditions. Logistical and economic issues as well as public and regulatory authority acceptance should also be considered when assessing the suitability of a species as a biomonitor.