Effects of Habitat Fragmentation on the Reproductive Ecology of Four Plant Species in Mallee Woodland

Abstract: Habitat fragmentation has the potential to affect plant reproduction by changing the community of pollinators and natural enemies, the neighborhood of potential mates, the availability of resources, and microclimate. I examined the effect of habitat fragmentation on reproduction of four species found in mallee woodlands of central New South Wales, Australia: Acacia brachybotrya , Senna artemisioides , Eremophila glabra , and Dianella revoluta . At six sites I surveyed plants in a reserve and in a nearby linear strip of vegetation. Two additional sites were established in a large reserve. Many effects were apparent at the extreme end of fragmentation, revealed by two-way analysis of covariance comparing reserves and linear strips at each site. The nature of the response differed among species. Flower production was greater in most linear strip fragments for S. artemisioides and E. glabra . Fruit set efficiency was significantly greater in linear strips for S. artemisioides and significantly lower for A. brachybotrya , E. glabra , and D. revoluta . Fruit predation was lower in most linear strips for E. glabra . For A. brachybotrya , fruit predation was significantly lower in linear strips. The net effect of these changes was a significant increase in whole-plant seed production for S. artemisioides , a significant decrease in whole-plant seed production for A. brachybotrya and in whole-plant fruit production for D. revoluta , and no consistent effect on whole-plant fruit production for E. glabra . In contrast, the only pattern apparent when the effect of fragment size was considered over a range from linear strips <40 m wide to a reserve> 140,000 ha was a positive correlation between the fragment size and fruit-set efficiency of A. brachybotrya . These results suggest that habitat fragmentation can significantly alter important reproductive functions of species, by changing both the plant's physical environment and its interactions with animals.     

Effect of biosurfactants on crude oil desorption and mobilization in a soil system

Microbially produced biosurfactants were studied to enhance crude oil desorption and mobilization in model soil column systems. The ability of biosurfactants from Rhodococcus ruber to remove the oil from the soil core was 1.4-2.3 times greater than that of a synthetic surfactant of suitable properties, Tween 60. Biosurfactant-enhanced oil mobilization was temperature-related, and it was slower at 15 degrees C than at 22-28 degrees C. Mathematical modelling using a one-dimensional filtration model was applied to simulate the process of oil penetration through a soil column in the presence of (bio)surfactants. A strong positive correlation (R(2)=0.99) was found between surfactant penetration through oil-contaminated soil and oil removal activity. Biosurfactant was less adsorbed to soil components than synthetic surfactant, thus rapidly penetrating through the soil column and effectively removing 65-82% of crude oil. Chemical analysis showed that crude oil removed by biosurfactant contained a lower proportion of high-molecular-weight paraffins and asphaltenes, the most nonbiodegradable compounds, compared to initial oil composition. This result suggests that oil mobilized by biosurfactants could be easily biodegraded by soil bacteria. Rhodococcus biosurfactants can be used for in situ remediation of oil-contaminated soils.     

Influence of mercury and selenium chemistries on the progression of cardiomyopathy in pygmy sperm whales, Kogia breviceps

More than half of pygmy sperm whales (Kogia breviceps) that strand exhibit signs of cardiomyopathy (CMP). Many factors may contribute to the development of idiopathic CMP in K. breviceps, including genetics, infectious agents, contaminants, biotoxins, and dietary intake (e.g. selenium, mercury, and pro-oxidants). This study assessed trace elements in K. breviceps at various stages of CMP progression using fresh frozen liver and heart samples collected from individuals that stranded along US Atlantic and Gulf coasts between 1993 and 2007. Standard addition calibration and collision cell inductively coupled plasma mass spectrometry (ICP-MS) were employed for total Se analysis and pyrolysis atomic absorption (AA) was utilized for total Hg analysis to examine if the Se/Hg detoxification pathway inhibits the bioavailability of Se. Double spike speciated isotope dilution gas chromatography ICP-MS was utilized to measure methyl Hg and inorganic Hg. Immunoblot detection and colorimetric assays were used to assess protein oxidation status. Data collected on trace elements, selenoproteins, and oxidative status were evaluated in the context of animal life history and other complementary histological information to gain insight into the biochemical pathways contributing to the development of CMP in K. breviceps. Cardiomyopathy was only observed in adult pygmy sperm whales, predominantly in male animals. Both Hg:Se molar ratios and overall protein oxidation were greater in males than females and increased with progression of CMP.     

Blood mercury levels among fish consumers residing in areas with high environmental burden

Mercury is a ubiquitous, persistent toxicant found in the environment. In water, mercury bioaccumulates up the food chain and leads to high concentrations in fish. Consumption of contaminated fish is the major source of exposure to mercury in the US. The objective of this study was to enroll persons living in areas selected by the Environmental Protection Agency (EPA) to have high mercury concentrations and who consume at least 6 oz of locally caught fish per week to determine the feasibility of monitoring future trends among a population identified as highly exposed. Blood samples were collected at time of interview and analyzed for mercury. Participants (n = 287) were enrolled from North Carolina, Maryland, and South Dakota. Participants reported eating an average of five servings of fish per week. The overall geometric mean for total mercury was 0.75 μg L⁻¹, with North Carolina having the highest mean level (2.02 μg L⁻¹). Overall, 42% of the study population had levels greater than the US geometric mean 0.83 μg L⁻¹. The number of servings of fish consumed was not found to be associated with blood mercury levels. We were able to identify some persons with elevated mercury concentrations living in areas identified by EPA; however, identifying and monitoring a highly exposed population over time would be challenging.     

Animal-related injuries: a population-based study of a five-state region in the upper Midwest: Regional Rural Injury Study II

PROBLEM: While agricultural injury has been identified among the major causes of occupational injury mortality and morbidity, data have been limited pertinent to the magnitude, consequences, and potential risk factors for animal-related injuries -- a major source of morbidity among agricultural operations. METHODS: Demographics, exposure, and injury data were collected for 1999 and 2001 among agricultural households in a five-state region. Causal models facilitated survey design, data analyses, and interpretation of results; directed acyclic graphs guided multivariate modeling. RESULTS: From 7,420 households (84% response of eligible), a total of 5,045 injury events were reported; 1,016 (20.1%) were animal-related. Multivariate analyses revealed increased risks for those <20 years; residents of all states compared to Minnesota; all age groups compared to 0-4 years; >0 hours worked; and prior agricultural injury history. For those 20+ years, increased risks were identified for: South Dakota residents; males; >0 hours worked; and prior agricultural injury history. For those cases <20 and 20+ years of age, 58% and 46%, respectively, resulted in lost work time on their agricultural operations (31% and 50%, one week or more). CONCLUSIONS: Animal-related injury has a major impact on the agricultural industry. Results serve as a basis for interventions and further research. IMPACT ON INDUSTRY: The impact of animal-related injuries on the agricultural industry appears significant; among age groups <20 and 20+, 85% and 82%, respectively, had some resulting restriction. For all events combined, 29% and 30%, respectively, involved restriction from one week to 3+ months; 12% and 15% involved restriction for one month or more. Among those <20 and 20+ years of age, 58% and 46%, respectively, lost work time on their own agricultural operation as a result of injuries associated with their own operation; 22% and 15% lost one week or more. Moreover, of the non-agriculture-related injuries, 31% and 50% resulted in lost work time on their own operation; 15% and 28%, respectively, lost one week or more. Restrictions such as these can affect the productivity of the operation, resulting in financial impacts, especially on small operations that have few people to manage the required tasks.     

Protecting the planet and its people: how do interventions to promote environmental sustainability and occupational safety and health overlap?

Problem: The challenges of both occupational safety and health and environmental sustainability require large-scale behavior change for meaningful improvements to occur. Environmental sustainability, or the ‘green movement’ has received far more attention recently, and certain strategies and recommendations from interventions designed for promoting pro-environmental behaviors may inform efforts to intervene on critical behaviors for improving occupational safety and health. Method: A survey of the literature regarding behavioral interventions for both environmental sustainability and occupational safety and health was conducted. Several theoretical approaches are reviewed, and successful approaches from each domain are identified, as well as parallel challenges and points for crossover. Recommendations are provided for adapting environmental sustainability intervention approaches for occupational safety and health applications. Impact on Industry: Safety and health leaders may achieve sustainable improvements in worker safety and health by harnessing the momentum of the green movement and adapting successful intervention approaches from the environmental sustainability domain.     

Incident, accident, catastrophe: cyanide on the Danube

It has been described as the worst disaster since Chernobyl. In January 2000, a retaining wall failed at the Aurul gold processing plant in Romania, releasing a wave of cyanide and heavy metals that moved quickly from one river to the next through Romania, Hungary, the Federal Republic of Yugoslavia and Bulgaria, killing tens of thousands of fish and other forms of wildlife and poisoning drinking-water supplies. This paper examines how and why the chemical spill at Baia Mare occurred and how responses to it emerged from circumstances at the global, local and immediate levels. The spill demonstrates the importance of the flow of information in framing and interpreting disasters, suggesting that such an event can go unnoticed or be viewed as catastrophic, depending on the political, historical and personal struggles that lead to its publicity. The paper offers a framework for understanding why the spill was alternately perceived as an incident, an accident and a catastrophe based on changing perceptions of culpability.