What Exactly Is an Endangered Species? An Analysis of the U.S. Endangered Species List: 1985–1991

Critics of the Endangered Species Act have asserted that is protects an inordinate number of subspecies and populations, in addition to full species, and that the scientific rationale for listing decisions is absent or weak. We reviewed all U.S. plants and animals proposed for listing or added to the endangered species list from 1985 through 1991 to determine the relative proportion of species, subspecies, and populations, and their rarity at time of listing. Approximately 80% of the taxa added to the list were full species, 18% were subspecies, and 2% were distinct populations segments of more widespread vertebrate species. The proportion of subspecies and populations was considerably higher among birds and mammals than among other groups. The median populations size at time of listing for vertebrate animals was 1075 individuals; for invertebrate animals it was 999. The median population size of a plant at time of listing was less than 120 individuals. Earlier listing of declining species could significantly improve the likelihood of successful recovery, and it would provide land managers and private citizens with more options for protecting vanishing plants and animals at less social or economic cost.     

Cost‐Effective Sediment Dredge Disposal Options for Small Craft Harbors in Canada

Sediment dredge disposal options were reviewed to improve cost‐effectiveness and environmental safety for dredging of coastal sediments at the Department of Fisheries and Oceans Small Craft Harbours (DFO‐SCH) program in Canada. Historically, contaminated dredge sediments exceeding federal guidelines were disposed of in nearby landfills. Recent federal regulatory changes in sediment quality guidelines adopted by provincial regulators in Canada has resulted in updates to guidelines for disposal of contaminated solids in landfills. Updates now require specific and general disposal options for contaminated dredge material destined for land‐based disposal, resulting in more expensive disposal in containment cells (if contaminated sediments exceed federal guidelines). However, as part of this study, a leachate testing method was applied to contaminated sediments to simulate migration of potential contaminants in groundwater. Using this approach, leachate quality was compared to federal freshwater criteria and drinking water quality guidelines for compliance with new regulations. Leachate testing performed on the highest sediment contaminant concentrations triggered less than 2 percent potable water exceedances, meaning that most dredge spoils could be disposed of in privately owned or provincially operated landfill sites, providing less expensive disposal options compared to containment cell disposal. Current dredge disposal practices were reviewed at 35 harbor sites across Nova Scotia and their limitations identified in a gap analysis. Improved site management was developed following this review and consultation with interested marine stakeholders. New disposal options and chemical analyses were proposed, along with improvements to cost efficiencies for management of dredged marine sediments in Atlantic Canada. © 2013 Wiley Periodicals, Inc.     

Biological Effects of Carbon Monoxide vs. Whole Emissions from Engine with Catalyst

The introduction of oxidizing catalytic converters in the exhaust system of automobiles has been found to be effective in reducing carbon monoxide, total hydrocarbons, and some other components of tailpipe emissions. The utilization of these converters, however, has also caused further oxidation of sulfur compounds producing an increased amount of sulfur trioxide (SO₃) which yields sulfuric acid and sulfates.¹ Studies on the biological effects of these sulfur compounds are in progress in our laboratory and preliminary findings are reported separately. This paper compares the biological effects of exposure to whole emissions from engines with and without converter and exposure to carbon monoxide alone.     

Perceptions of the security and attractiveness of urban parking lots

This study concerns design features of urban parking lots which can increase the perception of such areas as both safe and attractive. College students evaluated the attractiveness and perceived security associated with 180 scenes of parking lots adjacent to commercial and multi-family residential structures in Atlanta and Athens, Georgia, U.S.A. High intergroup correlations (r > 0·90) indicated the reliability of evaluations of both perceived features. Regressions of physical features on perceived security ratings and attractiveness ratings yielded highly predictive models (R² = 0·76 and 0·80, respectively). For both sets of ratings a Maintenance and Design factor accounted for the most variance. Although attractiveness ratings were higher as the total amount of vegetation increased in a scene, security was in general rated higher only when vegetation was well maintained and appeared to be installed as part of a landscape design. Attractiveness was generally higher for multi-family residential scenes than for commercial scenes. Perceived security was higher for frontal views of structures, especially when entrances were proximate to the viewer. Research implications are discussed in terms of the impact of natural features in urban areas for increasing attractiveness and reducing fear of crime.     

Preparation of high molecular weight DNA from hermatypic corals and its use for DNA hybridization and cloning

Previous attempts to extract high molecular weight DNA from hermatypic corals have failed because the starting material was mature tissue. The following paper describes the isolation of DNA from coral sperm which is of high molecular weight, and is suitable for DNA hybridization, digestion with restriction endonucleases and cloning. Gross DNA hybridization and hybridization with cloned repetitive DNA was used to investigate relatedness amongst members of the scleractinian coral family Acroporidae. Acropora formosa and A. pulchra were found to share a common (highly homologous) DNA sequence repeat; a related but less homologous sequence was present in A. latistella, and no homologous sequence was detected in Montipora digitata. These results imply a close taxonomic relationship between A. formosa and A. pulchra, and suggest that molecular criteria of this sort will be extremely useful in coral taxonomy.     

Highly repeated DNA sequences in the scleractinian coral genusAcropora: Evaluation of cloned repeats as taxonomic probes

A plasmid clone containing highly repeated DNA sequence fromAcropora formosa was used to probe slot blots of genomic DNA and Southern blots of Taq I digests from other Acroporidae. Homologous repeated DNA sequences were detected in 12 otherAcropora species, but not in three other species of Acroporidae (Astreopora sp.,Montipora digitata andM. aequituberculata). Slot-blot experiments indicated that the repeated sequences inAcropora latistella, A. tenuis, A. longicyathus andA. nobilis were distantly homologous with the clonedA. formosa repeat, whereas those inA. pulchra, A. millepora, A. valida, A. hyacinthus andA. microphthalma were highly homologous with this probe and those inA. digitifera were intermediate. Relatedness of the highhomology group toA. formosa was assessed by comparison of Taq I-digestion patterns. The predominant repeats inA. pulchra andA. hyacinthus had two Taq I sites per repeat unit (as didA. formosa), whereas repeats inA. digitifera, A. valida andA. microphthalma had one Taq I site per repeat; the pattern given byA. millepora implied that its highly homologous repeat units contained either one or two Taq I sites. Within the high-homology group, decreasing number of Taq I sites implies increasing taxonomic distance fromA. formosa. The relatedness series implied by these data differs from that based on morphological criteria.     

A passive sampling method for radiocarbon analysis of atmospheric CO2 using molecular sieve

Radiocarbon (¹⁴C) analysis of atmospheric CO₂ can provide information on CO₂ sources and is potentially valuable for validating inventories of fossil fuel-derived CO₂ emissions to the atmosphere. We tested zeolite molecular sieve cartridges, in both field and laboratory experiments, for passively collecting atmospheric CO₂. Cartridges were exposed to the free atmosphere in two configurations which controlled CO₂ trapping rate, allowing collection of sufficient CO₂ in between 1.5 and 10 months at current levels. ¹⁴C results for passive samples were within measurement uncertainty of samples collected using a pump-based system, showing that the method collected samples with ¹⁴C contents representative of the atmosphere. δ¹³C analysis confirmed that the cartridges collected representative CO₂ samples, however, fractionation during passive trapping means that δ¹³C values need to be adjusted by an amount which we have quantified. Trapping rate was proportional to atmospheric CO₂ concentration, and was not affected by exposure time unless this exceeded a threshold. Passive sampling using molecular sieve cartridges provides an easy and reliable method to collect atmospheric CO₂ for ¹⁴C analysis.