Work stress and the stress-buffering roles of work and family resources

This paper describes the development of the Work Environment Scale, which includes measures of perceived stressful and supportive aspects of the job milieu. This scale is used to examine stressful effects of the work environment on personal functioning and the stress-buffering value of work and family social resources among a representative community group of men and women. Work stressors had a greater impact on men, but supportive social resources provided more attenuation of such effects among men than among women. Although work stressors generally had less effect on men whose wives were employed, high stress in the women's work settings had some indirect negative consequences for their husbands. Reprint requests should be directed to the authors, Social Ecology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University Medical School, Stanford, California 94305, U.S.A.     

Coping with an intra-institutional relocation: behavioral change as a function of residents' personal resources

A model of person-environment interaction was used to help explain the impact of an intra-institutional relocation on the behavior of residents who varied in mobility and mental status. Environmental measures indicated that the new building provided more prosthetic features, fewer orientational aids, a more complex floorplan, and increased distance between the social areas and the nurses' stations. Behavioral observations of a sample of 17 residents showed varying adaptations to these environmental changes. Wheelchair-mobile residents benefited from the improved accessibility, whereas immobile residents experienced reduced stimulation and further restriction of their spatial range. High mental status residents were drawn out of their bedrooms into social spaces. while low mental status residents spent less time in social areas and more in the halls near the nurses' stations, where they could maintain contact with the staff. Information such as this on the differential impact of a new building can contribute to the design process and to program modification aimed at optimizing resident functioning.     

The influence of size-specific indirect interactions in predator-prey systems

Nonlethal indirect interactions between predators often lead to nonadditive effects of predator number on prey survival and growth. Previous studies have focused on systems with at least two different predator species and one prey species. However, most predators undergo extreme ontological changes in phenotype such that interactions between different-sized cohorts of a predator and its prey could lead to nonadditive effects in systems with only two species. This may be important since different-sized individuals of the same species can differ more in their ecology than similar-sized individuals of different species. This study examined trait-mediated indirect effects in a two-species system including a cannibalistic predator with different-sized cohorts and its prey. I tested for these effects using larvae of two stream salamanders, Gyrinophilus porphyriticus (predator) and Eurycea cirrigera (prey), by altering the densities and combinations of predator size classes in experimental streams. Results showed that the presence of large individuals can significantly reduce the impact of density changes of smaller conspecifics on prey survival through nonlethal means. In the absence of large conspecifics, an increase in the relative frequency of small predators significantly increased predation rates, thereby reducing prey survival. However, with large conspecifics present, increasing the density of small predators did not decrease prey survival, resulting in a 14.3% lower prey mortality than predicted from the independent effects of both predator size classes. Small predators changed their microhabitat use in the presence of larger conspecifics. Prey individuals reduced activity in response to large predators but did not respond to small predators. Both predators reduced prey growth. These results demonstrate that the impact of a predator can be significantly altered by two different types of trait-mediated indirect effects in two-species systems: between different-sized cohorts and between different cohorts and prey. This study demonstrates that predictions based on simple numerical changes that assume independent effects of different size classes or ignore size structure can be strongly misleading. We need to account for the size structure within predator populations in order to predict how changes in predator abundance will affect predator-prey dynamics.