Organic matter breakdown in streams in a region of contrasting anthropogenic land use.

Streams provide ecosystem services to humans that depend on ecosystem functions, such as organic matter breakdown (OMB). OMB can be affected by land use-related disturbance. We measured OMB in 29 low-order streams in a region of contrasting land use in south-west Germany to quantify land use effects on OMB. We deployed fine and coarse mesh leaf bags in streams of forest, agricultural, vinicultural and urban catchments to determine the microbial and invertebrate-mediated OMB, respectively. Furthermore, we monitored physicochemical, geographical and habitat parameters to explain potential differences in OMB among land use types and sites. Only microbial OMB differed between land use types. Microbial OMB was negatively correlated with pH and invertebrate-mediated OMB was positively correlated with tree cover. Generally, OMB responded to stressor gradients rather than directly to land use. Therefore, the monitoring of specific stressors may be more relevant than land use to detect effects on ecosystem functions, and to extrapolate effects on functions, e.g. in the context of assessing ecosystem services.

Do predictions from Species Sensitivity Distributions match with field data?

Species Sensitivity Distribution (SSD) is a statistical model that can be used to predict effects of contaminants on biological communities, but only few comparisons of this model with field studies have been conducted so far. In the present study we used measured pesticides concentrations from streams in Germany, France, and Finland, and we used SSD to calculate msPAF (multiple substance potentially affected fraction) values based on maximum toxic stress at localities. We compared these SSD-based predictions with the actual effects on stream invertebrates quantified by the SPEARpesticides bioindicator. The results show that the msPAFs correlated well with the bioindicator, however, the generally accepted SSD threshold msPAF of 0.05 (5% of species are predicted to be affected) severely underestimated the observed effects (msPAF values causing significant effects are 2-1000-times lower). These results demonstrate that validation with field data is required to define the appropriate thresholds for SSD predictions.

Review on the effects of toxicants on freshwater ecosystem functions.

We reviewed 122 peer-reviewed studies on the effects of organic toxicants and heavy metals on three fundamental ecosystem functions in freshwater ecosystems, i.e. leaf litter breakdown, primary production and community respiration. From each study meeting the inclusion criteria, the concentration resulting in a reduction of at least 20% in an ecosystem function was standardized based on median effect concentrations of standard test organisms (i.e. algae and daphnids). For pesticides, more than one third of observations indicated reductions in ecosystem functions at concentrations that are assumed being protective in regulation. Moreover, the reduction in leaf litter breakdown was more pronounced in the presence of invertebrate decomposers compared to studies where only microorganisms were involved in this function. High variability within and between studies hampered the derivation of a concentration-effect relationship. Hence, if ecosystem functions are to be included as protection goal in chemical risk assessment standardized methods are required.

SPEAR indicates pesticide effects in streams--comparative use of species- and family-level biomonitoring data.

To detect effects of pesticides on non-target freshwater organisms the Species at risk (SPEAR(pesticides)) bioindicator based on biological traits was previously developed and successfully validated over different biogeographical regions of Europe using species-level data on stream invertebrates. Since many freshwater biomonitoring programmes have family-level taxonomic resolution we tested the applicability of SPEAR(pesticides) with family-level biomonitoring data to indicate pesticide effects in streams (i.e. insecticide toxicity of pesticides). The study showed that the explanatory power of the family-level SPEAR(fm)(pesticides) is not significantly lower than the species-level index. The results suggest that the family-level SPEAR(fm)(pesticides) is a sensitive, cost-effective, and potentially European-wide bioindicator of pesticide contamination in flowing waters. Class boundaries for SPEAR(pesticides) according to EU Water Framework Directive are defined to contribute to the assessment of ecological status of water bodies.

Change in adult self-esteem: a longitudinal assessment.

This is a longitudinal investigation of self-esteem change in an adult population. The analysis addresses two limitations in earlier studies: the use of convenience samples of children and adolescents, and cross-sectional or short-duration longitudinal studies of self-esteem change. Participants are 97 randomly selected married couples interviewed at two points in time separated by 13 years. Two components of the self were measured: self-esteem and reflected appraisals (perception of others' evaluation). Contrary to previous research on self-esteem change, a significant decline was found in all components of the self for both husbands and wives. The decline in self-esteem was not a function of age, education or income. The decline was more likely to occur for high, rather than low, self-esteem participants. This finding is attributed to the demands on higher self-esteem participants to maintain or enhance self-esteem and the caution of low self-esteem participants to engage in behaviours that would threaten the self.

Marital food interaction and dietary behavior.

The objective of this investigation is to consider the role of family food interaction in healthful dietary activity. A theoretical model is proposed in which three sets of determinate variables are specified as leading to interaction in the family on food issues which, in turn, is predicted to have a positive effect on four indicators of dietary quality. 155 married couples from a midwestern US state were randomly selected and interviewed. The findings provide clear evidence of the importance of family food interaction for the quality of marital partners' diet. Also differences found between husbands and wives indicate that wives contribute more to husbands' dietary quality than the reverse, suggesting again the dominant status of wives in family food selection and preparation.

Predicting fat in diets of marital partners using the health belief model.

The objective of this investigation is to use the health belief model (HBM) to explain the percentage of calories from fat in the diet (PCF) for marital partners. The model includes four sets of determinate variables: perceived threat of a high-fat diet, barriers to a healthier diet, food choices made for health reasons, and self-efficacy, as well as sociodemographic background factors. One hundred fifty-five married couples were selected by a random area sample from the state of Iowa. Husbands and wives were interviewed separately in the home. The results partially support the HBM as applied to a nutrition domain and revealed interesting gender differences. For wives the cost of healthy diet changes had an effect on PCF. For husbands, perceived threat and self-efficacy had an effect on PCF. The differences are discussed on the basis of gender roles in the home and gender socialization.

Self-esteem agreement in the marital relationship.

With the use of the circular-causal model of relationship development, this study examined the convergence of the self-esteem of marriage partners over four martial life stages. Three hundred thirty-six married couples in the United States were randomly selected and divided into four life stage groups: younger couples with a child (or children) under age 6; couples with children in school; empty nest couples, in which the wife is in the age range of 45-59 years; and retired couples. Measures of a partner's self-esteem and his or her evaluation of the spouse's self-esteem were taken. The findings demonstrated a convergence of the partners' self-esteem across life stages.

Outcomes of equity/inequity among older spouses.

The extent to which perceptions of global and specific equity/inequity were associated with dissatisfaction, disagreement between spouses, partners' regard for one another, and gender-role attitudes was investigated for eighty-two couples over age sixty. The differential influence of equity/inequity for the well-being of women and men was studied.

Social-psychological factors in the dietary quality of married and single elderly.

The objective of this study was to examine the social-psychological correlates of diet quality of elderly married couples and elderly single women. The social-psychological factors included: personality, social interaction, and social influence variables. Eighty-two married couples (164 respondents) and 69 single women were randomly selected and interviewed. It was found that social influence variables were more important factors in determining quality of diet than either personality or social interaction variables. The elderly single women's higher quality diet was associated with more reliable sources of influence than those of the elderly married, a condition attributed to the independence and competencies required by their single living arrangements. For married couples, role dissatisfaction had negative consequences for wives' diets, and husbands' involvement in family food decisions had positive consequences for their own diet quality.

A comparison of depression among employed single-parent and married women.

This study of employed single-parent (n = 52) and married women (n = 87) investigated employment characteristics (time spent at work, income), psychological resources (self-esteem, sex-role attitudes), and management of domestic activities (evaluation and satisfaction with performance) in relation to depression. For the most part, correlates of depression were quite different for the two groups of women. Nontraditional sex-role attitudes, more time at work, higher income, low work-family strain, and high self-esteem were associated with less depression among single parents. Positive work orientation, high self-esteem, less time spent at work, and satisfaction with domestic tasks were linked with lower depression among married women.

Self-esteem discrepancies and depression.

This study examines the relationship between self-esteem discrepancies and depression in a long-term intimate relationship. It was hypothesized that depression is associated with discrepancies between married partner's self-appraisals, their perceptions of their spouses' appraisal of them, and their spouses' actual appraisal of them. Questions administered to 333 married couples (666 subjects) measured the three components of the self and depression. Absolute discrepancies were then correlated with depression. The findings provided support for the hypothesis.

Influences on food decisions across the family life cycle.

The objective of this study was to examine the effects of the family life cycle on factors that influence food habits. Three hundred thirty-six married couples representing our four family life cycle were randomly selected and interviewed. Each partner was asked how important 14 different sources of influence were on his/her food decisions. Sources of influence included media, classes, government information, significant others, and financial and health concerns. These sources had their greatest impact on young families who were establishing family food habits. Impact of these influences changed only moderately for other life cycle stages, indicating more stabilized food habits for these marriage partners. Wives were more influenced than husbands in each life cycle stage. Health concerns, cost, and nuclear family members were the most important sources of influence. Information from the media, government, food classes, and extension had little to moderate influence.

Factors affecting food behavior and the quality of husbands' and wives' diets.

One hundred sixteen husband-wife couples were interviewed to determine: (a) The influence of socioeconomic factors on their food behavior and (b) the relationship between these factors and the quality of their diets. According to the respondents, important sources of influence were: Personal preference, as determined by concern for taste and nutrition; influences of the immediate family; and cost. Factors external to the family, i.e., nutrition courses, the mass media, and reference groups, were perceived as having only slight influence. Factors which were significantly related to a better diet included the influence of the wife, a concern for personal and family health, nutrition classes, and nutritional information from the mass media.