The threatened status of restricted-range coral reef fish species

Coral reefs are the most diverse ecosystem in the sea. Throughout the world they are being overfished, polluted and destroyed, placing biodiversity at risk. To date, much of the concern over biodiversity loss has centred on local losses and the possibility of global extinction has largely been discounted. However, recent research has shown that 24% of reef fish species have restricted ranges (< 800 000 km(2)), with 9% highly restricted (< 50 000 km(2)). Restricted-range species are thought to face a greater risk of extinction than more widespread species since local impacts could cause global loss. We searched for information on status in the wild and characteristics of 397 restricted-range reef fish species. Fish body size, habitat requirements and usefulness to people were compared with those of a taxonomically-matched sample of more widespread species. We found that on average species with restricted ranges were significantly smaller (mean total length 19.1 cm versus 24.4 cm), tended to have narrower habitat requirements and were less used by people. Greater habitat specificity will tend to increase extinction risk while, if real, more limited usefulness (equivalent to exploitation) may reduce risk. Fifty-eight percent of restricted-range species were considered common/abundant in the wild and 42% uncommon/rare. Population status and threats to 319 species for which data were available were assessed according to the categories and criteria of the IUCN red list of threatened animals. A number of species were found to be rare, were exploited and had highly restricted ranges overlapping areas where reef degradation is particularly severe, placing them at a high risk of extinction. Five species were listed as Critically Endangered, two of them possibly already extinct in the wild, one as Endangered and 172 as Vulnerable. A further 126 species fell into Lower Risk categories and 11 were considered Data Deficient. Given the intensity of impacts to reefs, the broad geographical areas affected and the large numbers of restricted-range species, global extinctions seem likely. Urgent management action is now crucial for the survival of several species of reef fishes

Variation in individual growth rates and population abundances of ephemerellid mayflies

Individual growth and densities of six taxa of ephemerellid mayflies were examined in relation to differences in temperature and food among streams of western North America. For most taxa, growth rate was not a simple function of either temperature or food. Growth periods of taxa differed relative to seasonal changes in temperature. As a result of the interaction between size and temperature, growth rates and shapes of the growth curve varied among taxa. The significance of temperature for life history phenomena therefore cannot be easily generalized to explain phenological patterns among stream insects. Also, little evidence was found that implicated food as the cause for observed differences in growth rates among most sites. Growth rates in streams with high rates of algal production (open sites) were similar to growth rates in streams with low algal production (shaded sites). Only sites with long periods of ice cover, and presumably low availability of food, showed marked reduction in individual growth rates. Densities, however, varied strongly across sites: open streams had higher densities than shaded streams. These results imply that populations in streams may be near carrying capacity and that per capita food availability is similar among streams. The presence of such interactions between individual and population processes may help explain patterns at individual, population, and ecosystem levels of organization. Variation in Individual Growth Rates and Population Densities of Ephemerellid Mayflies. Available from: http://www.researchgate.net/publication/271857398_Variation_in_Individual_Growth_Rates_and_Population_Densities_of_Ephemerellid_Mayflies [accessed Jul 10, 2015]

The comparability of bioassessments: A review of conceptual and methodological issues

Differences in the raw data used in bioassessments and choices regarding how those data are analyzed and summarized can affect inferences regarding the status of ecological resources and, thus, the degree to which we can trust individual ecological assessments, compare assessments across different programs and regions, or share data when developing or refining new endpoint indices. Progress in addressing these issues has been hindered by lack of consensus regarding what a general definition of comparability should be in the context of bioassessments and what measures of comparability are appropriate for ecological data. In this paper, we review the state of knowledge regarding the comparability of assessments as affected by differences in raw data (composition and relative abundance of taxa), derived measures (biotic metrics and endpoint indices), and assessment levels (condition classes). We specifically address the extent to which the comparability of assessments can be compromised by systematic differences in data, discuss the factors known to affect data comparability, and consider the techniques available to evaluate and improve comparability. Rigorous assessment of data comparability should be a standard aspect of quality assurance when developing and applying biological indices. The comparability of bioassessments: A review of conceptual and methodological issues. - ResearchGate. Available from: http://www.researchgate.net/publication/251421037_The_comparability_of_bioassessments_A_review_of_conceptual_and_methodological_issues [accessed Jul 9, 2015]

Longitudinal and seasonal changes in functional organization of macroinvertebrate communities in four Oregon streams.

Relative numerical dominance and densities of invertebrate functional feeding groups are compared with longitudinal and seasonal changes in food resources in a Cascade Range stream system in Oregon. We also compare our data with hypothetical predictions of the River Continuum model. We found that both relative abundances and densities of functional groups fit qualitative characterization of stream reaches and the River Continuum model: Shredders dominated upper shaded reaches; scrapers were most important in intermediate—sized sections; collectors increased in importance progressively downstream; predators were nearly constant in relative abundance at all sections; other functional groups were either rare or only locally abundant. Seasonal shifts also occurred but were not as dramatic as longitudinal differences. Correlation analyses between quantitative measures of food sources and functional group abundance were usually significant. Lack of significance for some correlations is likely due to inaccurate characterization of food availability, but small size and improper classification of species\u27 feeding behavior also may be important. In addition, invertebrate densities and food standing crop are static parameters and only approximately reflect the dynamics of consumer production and food availability. Read More: http://www.esajournals.org/doi/abs/10.2307/193671

A Technique for the Nondestructive Detection of Voids and Composition Anomalies in Metal Matrix Composite Wires Using X or γ Rays

An initial study of a technique proposed for the nondestructive testing of metal matrix composites is the subject of this paper. These composites are manufactured in the form of approximately 1/2-mm-diameter “precursor” wires. Larger structures are fabricated by diffusion bonding of lay-ups. Reliable nondestructive quality control indicators of wire integrity have not yet been developed although a number of possibilities are being examined.1 Testing of the precursor wires is difficult because current manufacturing processes produce wires that may be entirely satisfactory but that vary in cross-sectional geometry, in surface properties, and sometimes in the amount of matrix material that is present. Techniques based on observations of wire resistance, surface emissivity, and sound emission signatures are difficult to interpret because of these characteristics. Wire imaging using x-ray or neutron techniques is also difficult because large lengths of wire must be examined with a resolution in the plane of the wire exceeding 50 line pairs per millimeter

System for the measurement of ultra-low stray light levels

An apparatus is described for measuring the effectiveness of stray light suppression light shields and baffle arrangements used in optical space experiments and large space telescopes. The light shield and baffle arrangement and a telescope model are contained in a vacuum chamber. A source of short, high-powered light energy illuminates portions of the light shield and baffle arrangement and reflects a portion of same to a photomultiplier tube by virtue of multipath scattering. The resulting signal is transferred to time-channel electronics timed by the firing of the high energy light source allowing time discrimination of the signal thereby enabling the light scattered and suppressed by the model to be distinguished from the walls and holders around the apparatus

Public geographies II: being organic

This second report on ‘public geographies' considers the diverse, emergent and shifting spaces of engaging with and in public/s. Taking as its focus the more ‘organic’ rather than ‘traditional’ approach to doing public geography, as discussed in the first report, it explores the multiple and unorthodox ways in which engagements across academic-public spheres play out, and what such engagements may mean for geography/ers. The report first explores the role of the internet in ‘enabling conversations', generating a range of opportunities for public geography through websites, wikis, blogs, file-sharing sites, discussion forums and more, thinking critically about how technologies may enable/disable certain kinds of publically engaged activities. It then considers issues of process and praxis: how collaborations with groups/communities/organizations beyond academia are often unplanned, serendipitous encounters that evolve organically into research/learning/teaching endeavours; but also that personal politics/positionality bring an agency to bear upon whether we, as academics, follow the leads we may stumble upon. The report concludes with a provocative question – given that many non-academics appear to be doing some amazing and inspiring projects and activities, thoughtful, critical and (arguably) examples of organic public geographies, what then is academia’s role

Fecal Sludge Management: a comparative assessment of 12 cities

This paper outlines the findings of a fecal sludge management (FSM) initial scoping study in twelve cities. This short, desk-based study used innovative tools to assess the institutional context and the outcome in terms of the amount of fecal sludge safely managed. A range of cities was included in the review, all in low- and middle-income countries. None of the cities studied managed fecal sludge effectively, although performance varied. Where cities are seeking to address fecal sludge challenges the solutions are, at best, only partial, with a focus on sewerage which serves a small minority in most cases. FSM requires strong city-level oversight and an enabling environment that drives coordinated actions along the sanitation service chain; this was largely absent in the cities studied. Based on the findings of the review a typology of cities was developed to aid the identification of key interventions to improve FSM service delivery. Additional work is recommended to further improve the tools used in this study in order to enable better understanding of the FSM challenges and identify appropriate operational solutions