Can the ratio of aromatic skeletons explain cross-species responses within evolutionarily conserved Ostariophysan alarm cues?: testing the purine-ratio hypothesis

Summary. While the response to damage-released chemical alarm cues within the superorder Ostariophysi appears to be highly conserved across species, it is generally observed that the intensity of response to heterospecific alarm cues decreases with increasing phylogenetic distance. Recent studies have demonstrated that purine-N-oxides function as chemical alarm cues within Ostariophyian fishes and that the nitrogen-oxide functional group is conserved as the chief molecular trigger. According to the purine-ratio hypothesis, these cross-species differences may be due to the relative proportion of different carrier compounds associated with the nitrogen-oxide molecular trigger. To test this hypothesis, we exposed glowlight tetras (Hemigrammus erythrozonus, Characidae, Ostariophysi) to one of five synthetic stimuli (hypoxanthine-3-N-oxide (H3NO), pyridine-N-oxide (PNO) or mixed stimuli of 75 % H3NO-25 % PNO, 50 % H3NO-50 % PNO, or 25 % H3NO-75 % PNO), natural conspecific chemical alarm cue or a distilled water control. We quantified changes in shoal cohesion and vertical area use as species typical indicators of an antipredator response. As predicted, response intensity decreased as the ratio of hypoxanthine-3-N-oxide to pyridine-N-oxide decreased and the strongest response was to natural alarm cue. These results suggest that species-specific carrier compounds may account for the well-documented cross-species differences in the response to heterospecific alarm cues within phylogenetically related taxa.     

Ecologically based management of rodents in the real world: applied to a mixed agroecosystem in Vietnam.

Rodents cause significant damage to lowland irrigated rice crops in the Red River Delta of Vietnam. A four-year study was conducted in 1999-2002 to examine the effectiveness of applying rodent control practices using the principles of ecologically based pest management. Four 100-150 ha study sites adjacent to villages were selected and farmers on two treated sites were asked to follow a set of rodent management practices, while farmers on the untreated sites were asked not to change their typical practices. Farmers on the treated sites were encouraged to use trap-barrier systems (TBS's; 0.065-ha early planted crop surrounded by a plastic fence with multiple capture traps; one TBS for every 10-15 ha), to work together over large areas by destroying burrows in refuge habitats soon after planting (before the rats reestablish in the fields and before the onset of breeding), synchronizing planting and harvesting of the their rice crops, cleaning up weeds and piles of straw, and keeping bund (embankment) size small (<30 cm) to prevent burrowing. A 75% reduction in the use of rodenticides and plastic barrier fences (without traps or an early crop) was achieved on treated sites. The abundance of rodents was low after implementation of the management practices across all sites. There was no evidence for an effect of treatment on the abundance of rodents captured each month using live-capture traps, and no difference in damage between treatments or in yields obtained from the rice crops. Therefore, ecologically based rodent management was equally effective as typical practices for rodent management. Farmers on the treated sites spent considerably less money applying rodent control practices, which was reflected in the comparative increase in the partial benefit:cost of applying ecologically based rodent management from 3:1 on treated sites and untreated sites prior to the implementation of treatments to 17:1 on treated sites in the final year of the project.     

Assessing competition between Steller sea lions and the commercial groundfishery in Alaska: A bioenergetics modelling approach

In the last three decades the western stock of the Steller sea lion (Eumetopias jubatus) has declined by more than 85%. Nutritional stress resulting in increased juvenile mortality is one of the leading hypotheses to account for this decline. Competition between Steller sea lions and the commercial groundfishery for walleye pollock (Theragra chalcogramma) has been proposed as a mechanism underlying the nutritional stress. In order to examine the competition component of the nutritional stress hypothesis, we developed a bioenergetics-based model to project the population trends of Steller sea lions under various scenarios of continued groundfish harvest. Annual energy budgets were calculated for the Gulf of Alaska population of Steller sea lions, and compared with projected available energy from walleye pollock under a variety of harvest scenarios. Model simulations produced 50-year Steller sea lion population projections consistent with current trends, as well as with published projections for stable and increasing populations from stable age distribution life table models. Model simulations were unable to produce energy deficits sufficient to account for the decline in Steller sea lions, but do suggest areas where existing data need supplementing.     

Kodak's safety performance indexing—a tool for environmental improvement

Safety performance has a direct effect on employees' productivity and quality of work life, and on company profits and image in the community. Enormous human and financial losses can result from poor safety performance, and all such losses are preventable. To prevent these potential losses, safety performance must be continually improved across all levels of the organization. Effective safety programs are the key to improved safety performance. But how do we know when a safety program is effective? How can we measure safety performance and set goals for improvements? How can we track progress toward these goals? This article demonstrates how a powerful performance management tool —performance indexing— can be used to help improve safety performance throughout your company. This tool can also be used to measure, track, and improve environmental and occupational health performance.     

Factors influencing transboundary wildlife management in the North American ‘Crown of the Continent’

Jurisdictional boundaries and borders are rarely coincident with ecological systems. The long-term persistence of viable wildlife populations and habitats, especially for highly mobile and migratory species, is contingent upon effective management that transcends administrative boundaries. Although transboundary natural resource management has emerged as a topic of academic and professional discourse, implementation has been hampered by a host of barriers that include institutional, administrative, financial and contextual factors. The Crown Managers Partnership, a collaborative initiative of public land managers in the transboundary Rocky Mountains of Canada and the United States, is exploring the approaches to overcome these barriers. This paper reports on the results of interviews to identify the factors that influence the management of transboundary wildlife and provides a series of recommendations that are specific to the study area context, but are also transferable to other regions. Formalizing the existing partnership, exploring options for expanding participation in the partnership to include non-government interests, engaging third party facilitation, using non-traditional data sources, applying metapopulation ecology theory, and interdisciplinary problem solving are all elements recommended for improved transboundary management and of wildlife in the Crown of the Continent Ecosystem.     

The politics of drought: The pauperization of lsiolo Boran

Isiolo Boran are becoming a population of permanent paupers. During the colonial period they were protected from Somali incursions, and their way of life preserved. Since Independence, however, largely as a result of increasing government intervention and market integration, they have become caught in a vicious spiral of poverty and decline.