Patterns of variation in tail ornament size in birds

In recent years several different kinds of sexual selection models have been developed, and tail ornaments in birds have frequently been used as an example of a sexually selected character where the models might apply. However, very little is known about intra- and interpopulation variation in ornament size. We have studied the elongated tail ornaments in four species of whydahs Vidua , the forktailed flycatcher Tyrannus savana and the Asian paradise flycatcher Terpsiphone paradisi. Ornaments were relatively longer in males with the longest tarsi ('heterogony' with positive allometry). Also, tail lengths were remarkably variable within each geographical area, the coefficient of variation (average = 11%) being three times as high as for body size characters. Models, with female preference of ornaments bearing no relation to male viability, usually generate lines of neutral equilibria. Thus, they predict extraordinary variation in ornaments between populations. However, elongated tail ornaments did not show higher geographical variation than the body size characters, suggesting that there is no line of equilibria for these ornaments.     

Comparison of European and US biological indicators for ethylene oxide sterilization

Summary Biological indicators (BIs) are used to monitor ethylene oxide (EO) gas sterilization processes for medical devices. Several European and United States BIs for EO sterilization were evaluated for resistance according to both United States Pharmacopeia (USP) XXI and United Kingdom's (UK) tests for D-values. US BIs areB. subtilis var. niger spores on paper strips or disc carriers while European BIs use aluminum strips, quartz sand, or cotton yarn. Numerous BIs per run and runs per lot, as well as 2–3 different lots of BIs from each manufacturer, were examined. Both British and US BIs met their respective label claims for rates of inactivation when tested against British and USP EO test parameters, respectively. However, Danish BIs, on cotton yarn or quartz sand, were not inactivated following USP specifications during the exposure dwell times tested (600 mg L^–1 EO, 54°C, 60% RH, 0–110 min). The Danish BIs will require further testing in order for us to determine if theirB. subtilis spores are unusually resistant to EO or if the spore carrier substrates protect the spores from the sterilizing gas. In conclusion, the British and American BIs for EO sterilization are equivalent in resistance despite differences in carrier substrate, recovery conditions, calculation methods for D-values, and the labeled sterilization conditions for use.     

The prevalence of root surface caries amongst Irish adults

In a national survey of adult dental health conducted in the Republic of Ireland in 1989/90 a total of 1,527 subjects aged 25 and older were examined for root surface caries. It was found that the prevalence of root surface caries was highest in older age groups and also amongst males, residents of non-fluoridated communities and those earning low incomes. Tooth loss masked the potential prevalence of root surface caries. With more persons retaining their natural teeth into middle and old age the prevalence of root surface caries is likely to increase in the future.     

The ecosystem approach to environmental assessment: moving from theory to practice

The ecosystem approach to environmental management is viewed by many as being fundamental to the development of appropriate management strategies. While this approach represents a major advance in the way researchers view environmental assessment, the approach in itself does not provide practical information as to what questions to ask and what tools to use in assessing and managing ecosystems. Similarly, the concept of ecosystem health, as it is usually defined, has little practical value for ecosystem managers. We suggest the next stage in environmental assessment will be the development of specific frameworks designed to assess individual ecosystems. Of primary importance is the need to consider the basic structure and function of the ecosystem itself. Such consideration, together with explicit identification of anthropogenic stresses particular to the system, serves to identify those components most at risk and those issues most deserving of attention. Researchers should explore critical linkages between environmental stressors and their observable, measurable and predictable effects on ecological parameters and use this understanding to develop a management strategy that incorporates appropriate ecological indicators. The importance of these considerations will be illustrated using examples from the Northern River Basins Study.     

A conceptual model for the assessment of depressional wetlands in the prairie pothole region

The U.S. Environmental Protection Agency's (EPA's), Environmental Monitoring and Assessment Program (EMAP) is developing a landscape-level conceptual model to evaluate the condition of depressional (basin-type) wetlands in the prairie pothole region (PPR) of the United States. This effort is underway to determine the current condition of the Nation's wetlands and to track how it is improving or degrading over time, as well as to identify management priorities over major geographic areas. The depressional wetlands in the PPR were selected by EMAP both because of the importance of this region for waterfowl and because of the efforts currently being conducted by federal agencies and academic institutions in this region. The PPR provides nesting habitat for more than 15 species of ducks, and supports as much as half of the total production of dabbling and diving ducks in North America. Wetlands in this area became a vulnerable resource after extensive draineage in the 1800s. We propose a conceptual model that represents a framework for guiding the development of ecological indicators, research activities, and data collection for the evaluation of wetland conditions. In princple, this conceptual model is applicable to wetlands in any part of the world.     

Chromosome numbers and differentiation of centrospermous families

The patterns of variation of chromosome numbers in theCentrospermae suggest a common ancestry of centrospermous anthocyanin and betalain families. Phylogenetic divergence in the order may have originated with progenitors similar to extantMolluginaceae, Aizoaceae orPhytolaccaceae taxa with x = 9. Evolutionary radiation and advancement in several lines then seems to have been paralleled by trends for increasing chromosome base numbers through dysploidy and polyploidy, e.g. towardsCaryophyllaceae, Portulacaceae-Basellaceae, Hectorellaceae, Cactaceae, Didieraceae, Nyctaginaceae andChenopodiaceae-Amaranthaceae. Presented in the Symposium Evolution of Centrospermous Families, during the XIIth International Botanical Congress, Leningrad, July 8, 1975.     

Searching for sustainability: are assessments of wildlife harvests behind the times?

The unsustainable harvest of wildlife is a major threat to global biodiversity and to the millions of people who depend on wildlife for food and income. Past research has called attention to the fact that commonly used methods to evaluate the sustainability of wildlife hunting perform poorly, yet these methods remain in popular use today. Here, we conduct a systematic review of empirical sustainability assessments to quantify the use of sustainability indicators in the scientific literature and highlight associations between analytical methods and their outcomes. We find that indicator type, continent of study, species body mass, taxonomic group and socio‐economic status of study site are important predictors of the probability of reported sustainability. The most common measures of sustainability include population growth models, the Robinson & Redford (1991) model and population trends through time. Indicators relying on population‐specific biological data are most often used in North America and Europe, while cruder estimates are more often used in Africa, Latin America and Oceania. Our results highlight both the uncertainty and lack of uniformity in sustainability science. Given our urgent need to conserve both wildlife and the food security of rural peoples around the world, improvements in sustainability indicators are of utmost importance.     

Short-term effects of wildfire on microbial biomass and abundance in black pine plantation soils in Turkey

Measurement of soil microbial biomass and abundance offers a means of assessing the response of all microbial populations to changes in the soil environment after a fire. We examined the effects of wildfire on microbial biomass C and N, and abundance of bacteria and fungi 2 months after a fire in a pine plantation. Soil organic carbon (C_org), total nitrogen (N_tot), and electrical conductivity (EC) increased following the fire. In terms of microbial abundance, the overall results showed that burned forest soils had the most bacteria and fungi. Microbial biomass C and N from soil in the burned forest were not significantly different from their unburned forest counterparts. However, microbial indices indicated that fire affects soil microbial community structure by modifying the environmental conditions. The results also suggested that low-intensity fire promotes microorganism functional activity and improves the chemical characteristics of soils under humid climatic conditions.