Are carrion resources as scarce as we think?

As humans, we tend to focus on the greener, living aspects of the environment and often forget the other side filled with death and decay. Carrion, the decaying flesh of dead animals, is a nutrient-rich, spatially patchy ephemeral resource, relied upon as a food by a variety of organisms. As a patchy and finite resource, carrion\u27s availability and distribution are unpredictable. Some factors that can influence the availability and production of carrion include predation, old age, and anthropogenic causes. Feeding on these resources are many scavengers, both facultative and obligate, vertebrate and arthropod. A primary consumer of carrion are blow flies (Diptera: Calliphoridae); often the first organisms to arrive at a decaying carcass. There are at least 11 blow fly species in SW Ontario, all requiring carrion resources for immature larval development yet manage to co-exist on what has been stated to be a rare, patchy ephemeral resource. My thesis will be testing the hypothesis that carrion resources are not as rare as previously considered and may be predicted using land-use attributes. Specifically, I will be using geospatial technology to model land-use attributes in the urban and rural areas of Essex County, Ontario. Some distinct elements of land-use being examined include farm, residential, commercial, and conservation. Following this, sites will be randomly chosen to trap blow flies across the gradient of land-use predicted to influence carrion availability, measuring blow fly species diversity along this gradient. This knowledge furthers our understanding of blow fly co-existence across a spatial and temporal landscape

Spatial Variability and Application of Ratios between BTEX in Two Canadian Cities

Spatial monitoring campaigns of volatile organic compounds were carried out in two similarly sized urban industrial cities, Windsor and Sarnia, ON, Canada. For Windsor, data were obtained for all four seasons at approximately 50 sites in each season (winter, spring, summer, and fall) over a three-year period (2004, 2005, and 2006) for a total of 12 sampling sessions. Sampling in Sarnia took place at 37 monitoring sites in fall 2005. In both cities, passive sampling was done using 3M 3500 organic vapor samplers. This paper characterizes benzene, toluene, ethylbenzene, o, and (m + p)-xylene (BTEX) concentrations and relationships among BTEX species in the two cities during the fall sampling periods. BTEX concentration levels and rank order among the species were similar between the two cities. In Sarnia, the relationships between the BTEX species varied depending on location. Correlation analysis between land use and concentration ratios showed a strong influence from local industries. Use one of the ratios between the BTEX species to diagnose photochemical age may be biased due to point source emissions, for example, 53 tonnes of benzene and 86 tonnes of toluene in Sarnia. However, considering multiple ratios leads to better conclusions regarding photochemical aging. Ratios obtained in the sampling campaigns showed significant deviation from those obtained at central monitoring stations, with less difference in the (m + p)/E ratio but better overall agreement in Windsor than in Sarnia

Possible Ballast Water Transfer of Lionfish to the Eastern Pacific Ocean

The Indo-Pacific Red Lionfish was first reported off the Florida coast in 1985, following which it has spread across much of the SE USA, Gulf of Mexico, and Caribbean Sea. Lionfish negatively impact fish and invertebrate assemblages and abundances, thus further spread is cause for concern. To date, the fish has not been reported on the Pacific coast of North or Central America. Here we examine the possibility of ballast water transfer of lionfish from colonized areas in the Atlantic Ocean to USA ports on the Pacific coast. Over an eight-year period, we documented 27 commercial vessel-trips in which ballast water was loaded in colonized sites and later discharged untreated into Pacific coast ports in the USA. California had the highest number of discharges including San Francisco Bay and Los Angeles-Long Beach. A species distribution model suggests that the probability of lionfish establishment is low for the western USA, Colombia and Panama, low to medium for Costa Rica, Nicaragua, El Salvador and Guatemala, medium to high for mainland Ecuador, and very high for western Mexico, Peru and the Galapagos Islands. Given the species’ intolerance of freshwater conditions, we propose that ballast water exchange be conducted in Gatún Lake, Panama for western-bound vessels carrying ‘risky’ ballast water to prevent invasion of the eastern Pacific Ocean

Variable δ15N Diet-Tissue Discrimination Factors among Sharks: Implications for Trophic Position, Diet and Food Web Models

The application of stable isotopes to characterize the complexities of a species foraging behavior and trophic relationships is dependent on assumptions of δ15N diet-tissue discrimination factors (∆15N). As ∆15N values have been experimentally shown to vary amongst consumers, tissues and diet composition, resolving appropriate speciesspecific ∆15N values can be complex. Given the logistical and ethical challenges of controlled feeding experiments for determining ∆ 15N values for large and/or endangered species, our objective was to conduct an assessment of a range of reported ∆ 15N values that can hypothetically serve as surrogates for describing the predator-prey relationships of four shark species that feed on prey from different trophic levels (i.e., different mean δ 15N dietary values). Overall, the most suitable species-specific ∆ 15N values decreased with increasing dietary-δ 15N values based on stable isotope Bayesian ellipse overlap estimates of shark and the principal prey functional groups contributing to the diet determined from stomach content analyses. Thus, a single ∆ 15N value was not supported for this speciose group of marine predatory fishes. For example, the ∆ 15N value of 3.7‰ provided the highest percent overlap between prey and predator isotope ellipses for the bonnethead shark (mean diet δ 15N = 9‰) whereas a ∆ 15N value \u3c 2.3‰ provided the highest percent overlap between prey and predator isotope ellipses for the white shark (mean diet δ 15N = 15‰). These data corroborate the previously reported inverse ∆ 15N-dietary δ 15N relationship when both isotope ellipses of principal prey functional groups and the broader identified diet of each species were considered supporting the adoption of different ∆ 15N values that reflect the predators’ δ 15N-dietary value. These findings are critical for refining the application of stable isotope modeling approaches as inferences regarding a species’ ecological role in their community will be influenced with consequences for conservation and management actions

Multi-season, multi-year concentrations and correlations amongst the BTEX group of VOCs in an urbanized industrial city

An air quality monitoring study focusing on spatial patterns was carried out in the urban industrial city of Windsor, Ontario, Canada (42.267°N, 82.95°W). This study took place over a three-year period (2004–2006), during all four seasons for a total of 12 two-week sampling periods (each with approximately 50 sites) at 162 sites across the city. Benzene, toluene, ethylbenzene, (m + p)-xylene, and o-xylene (BTEX) were measured using 3M #3500 Organic Vapor Samples (Guillevan, Montreal). Results from this investigation indicate that significant variability is present temporally (seasonally and annually) and spatially. The three-year mean concentrations in μg m−3 were: benzene (0.76), toluene (2.75), ethylbenzene (0.45), o-xylene (0.47), (m + p)-xylene (1.36), and total BTEX (5.64), with greater variability within each year compared with variability between the three years. Concentrations were highly correlated between most BTEX species, consistent with previous studies in urban areas. Toluene to benzene ratios were consistent between years, with the highest observed ratios occurring in summer, the lowest in winter, and fall and spring values falling in between. The range of ratios suggests that the majority of these two compounds originate from mobile emissions. (m + p)-Xylene to ethylbenzene ratios, used as indicators of photochemical age, showed a three-year mean of 3.0 with little spatial and temporal variability suggesting that relatively fresh and homogenous sources of these species are present in this area. The seasonal trends across the spatial network were representative of the seasonal patterns obtained at a long term monitoring station, with both methods indicating that fall and spring concentrations were preferred proxies of annual means. However, significant spatial variability of concentrations was observed. The upper range of concentrations compared with the values obtained at the central monitoring station differed by up to a factor of six, highlighting the importance of multiple sampling sites to reduce exposure misclassification. Significant correlations between seasons were observed in all three years, revealing a consistent rank order of high to low concentrations among the monitoring sites within a given year. Consideration of all analyses suggests that when resources are limited to a single sampling season, fall and spring mean values for concentrations and ratios seem to best represent the annual average in this city. Other study design consideration suggestions are also provided for future air quality research

Ballast water records

Shipping data from Caribbean to Pacific US coast from the years 2006-2013 for ships without BW

Data from: Possible ballast water transfer of lionfish to the eastern Pacific Ocean

The Indo-Pacific Red Lionfish was first reported off the Florida coast in 1985, following which it has spread across much of the SE USA, Gulf of Mexico, and Caribbean Sea. Lionfish negatively impact fish and invertebrate assemblages and abundances, thus further spread is cause for concern. To date, the fish has not been reported on the Pacific coast of North or Central America. Here we examine the possibility of ballast water transfer of lionfish from colonized areas in the Atlantic Ocean to USA ports on the Pacific coast. Over an eight-year period, we documented 27 commercial vessel-trips in which ballast water was loaded in colonized sites and later discharged untreated into Pacific coast ports in the USA. California had the highest number of discharges including San Francisco Bay and Los Angeles-Long Beach. A species distribution model suggests that the probability of lionfish establishment is low for the western USA, Colombia and Panama, low to medium for Costa Rica, Nicaragua, El Salvador and Guatemala, medium to high for mainland Ecuador, and very high for western Mexico, Peru and the Galapagos Islands. Given the species’ intolerance of freshwater conditions, we propose that ballast water exchange be conducted in Gatún Lake, Panama for western-bound vessels carrying ‘risky’ ballast water to prevent invasion of the eastern Pacific Ocean

Lionfish occurrence and environmental data

Lionfish occurrence data provided by the U.S. Geological Survey combined with environmental data provided by AquaMap

Development of temporally refined land-use regression models predicting daily household-level air pollution in a panel study of lung function among asthmatic children

Regulatory monitoring data and land-use regression (LUR) models have been widely used for estimating individual exposure to ambient air pollution in epidemiologic studies. However, LUR models lack fine-scale temporal resolution for predicting acute exposure and regulatory monitoring provides daily concentrations, but fails to capture spatial variability within urban areas. This study coupled LUR models with continuous regulatory monitoring to predict daily ambient nitrogen dioxide (NO2) and particulate matter (PM2.5) at 50 homes in Windsor, Ontario. We compared predicted versus measured daily outdoor concentrations for 5 days in winter and 5 days in summer at each home. We also examined the implications of using modeled versus measured daily pollutant concentrations to predict daily lung function among asthmatic children living in those homes. Mixed effect analysis suggested that temporally refined LUR models explained a greater proportion of the spatial and temporal variance in daily household-level outdoor NO2 measurements compared with daily concentrations based on regulatory monitoring. Temporally refined LUR models captured 40% (summer) and 10% (winter) more of the spatial variance compared with regulatory monitoring data. Ambient PM2.5 showed little spatial variation; therefore, daily PM2.5 models were similar to regulatory monitoring data in the proportion of variance explained. Furthermore, effect estimates for forced expiratory volume in 1 s (FEV1) and peak expiratory flow (PEF) based on modeled pollutant concentrations were consistent with effects based on household-level measurements for NO2 and PM2.5. These results suggest that LUR modeling can be combined with continuous regulatory monitoring data to predict daily household-level exposure to ambient air pollution. Temporally refined LUR models provided a modest improvement in estimating daily household-level NO2 compared with regulatory monitoring data alone, suggesting that this approach could potentially improve exposure estimation for spatially heterogeneous pollutants. These findings have important implications for epidemiologic studies — in particular, for research focused on short-term exposure and health effects