Genomic erosion in a demographically recovered bird species during conservation rescue

The pink pigeon (Nesoenas mayeri) is an endemic species of Mauritius that has made a remarkable recovery after a severe population bottleneck in the 1970s to early 1990s. Prior to this bottleneck, an ex situ population was established from which captive-bred individuals were released into free-living subpopulations to increase population size and genetic variation. This conservation rescue led to rapid population recovery to 400–480 individuals, and the species was twice downlisted on the International Union for the Conservation of Nature (IUCN) Red List. We analyzed the impacts of the bottleneck and genetic rescue on neutral genetic variation during and after population recovery (1993–2008) with restriction site-associated sequencing, microsatellite analyses, and quantitative genetic analysis of studbook data of 1112 birds from zoos in Europe and the United States. We used computer simulations to study the predicted changes in genetic variation and population viability from the past into the future. Genetic variation declined rapidly, despite the population rebound, and the effective population size was approximately an order of magnitude smaller than census size. The species carried a high genetic load of circa 15 lethal equivalents for longevity. Our computer simulations predicted continued inbreeding will likely result in increased expression of deleterious mutations (i.e., a high realized load) and severe inbreeding depression. Without continued conservation actions, it is likely that the pink pigeon will go extinct in the wild within 100 years. Conservation rescue of the pink pigeon has been instrumental in the recovery of the free-living population. However, further genetic rescue with captive-bred birds from zoos is required to recover lost variation, reduce expression of harmful deleterious variation, and prevent extinction. The use of genomics and modeling data can inform IUCN assessments of the viability and extinction risk of species, and it helps in assessments of the conservation dependency of populations.     

Multiple sources of predictive uncertainty in modeled estimates of net ecosystem CO2 exchange

Net ecosystem CO₂ exchange (NEE) is typically measured directly by eddy covariance towers or is estimated by ecosystem process models, yet comparisons between the data obtained by these two methods can show poor correspondence. There are three potential explanations for this discrepancy. First, estimates of NEE as measured by the eddy-covariance technique are laden with uncertainty and can potentially provide a poor baseline for models to be tested against. Second, there could be fundamental problems in model structure that prevent an accurate simulation of NEE. Third, ecosystem process models are dependent on ecophysiological parameter sets derived from field measurements in which a single parameter for a given species can vary considerably. The latter problem suggests that with such broad variation among multiple inputs, any ecosystem modeling scheme must account for the possibility that many combinations of apparently feasible parameter values might not allow the model to emulate the observed NEE dynamics of a terrestrial ecosystem, as well as the possibility that there may be many parameter sets within a particular model structure that can successfully reproduce the observed data. We examined the extent to which these three issues influence estimates of NEE in a widely used ecosystem process model, Biome-BGC, by adapting the generalized likelihood uncertainty estimation (GLUE) methodology. This procedure involved 400,000 model runs, each with randomly generated parameter values from a uniform distribution based on published parameter ranges, resulting in estimates of NEE that were compared to daily NEE data from young and mature Ponderosa pine stands at Metolius, Oregon. Of the 400,000 simulations run with different parameter sets for each age class (800,000 total), over 99% of the simulations underestimated the magnitude of net ecosystem CO₂ exchange, with only 4.07% and 0.045% of all simulations providing satisfactory simulations of the field data for the young and mature stands, even when uncertainties in eddy-covariance measurements are accounted for. Results indicate fundamental shortcomings in the ability of this model to produce realistic carbon flux data over the course of forest development, and we suspect that much of the mismatch derives from an inability to realistically model ecosystem respiration. However, difficulties in estimating historic climate data are also a cause for model-data mismatch, particularly in a highly ecotonal region such as central Oregon. This latter difficulty may be less prevalent in other ecosystems, but it nonetheless highlights a challenge in trying to develop a dynamic representation of the terrestrial biosphere.     

Correlation analysis between sulphate content and leaching of sulphates in recycled aggregates from construction and demolition wastes

In some recycled aggregates applications, such as component of new concrete or roads, the total content of soluble sulphates should be measured and controlled. Restrictions are usually motivated by the resistance or stability of the new structure, and in most cases, structural concerns can be remedied by the use of techniques such as sulphur-resistant cements. However, environmental risk assessment from recycling and reuse construction products is often forgotten. The purpose of this study is to analyse the content of soluble sulphate on eleven recycled aggregates and six samples prepared in laboratory by the addition of different gypsum percentages. As points of reference, two natural aggregates were tested. An analysis of the content of the leachable amount of heavy metals regulated by European regulation was included. As a result, the correlation between solubility and leachability data allow suggest a limiting gypsum amount of 4.4% on recycled aggregates. This limit satisfies EU Landfill Directive criteria, which is currently used as reference by public Spanish Government for recycled aggregates in construction works.     

Status and prospects of environmental protection in Hong Kong

Summary Environmental protection in Hong Kong traditionally has been neglected by the government and private sector, with citizens showing little interest. The overwhelming pre-occupation with economic growth and a plethora of pressing social needs are often cited as the main excuses for past apathy. Since the late 1970s, the government has taken positive steps to establish administrative structures and statutes to arrest environmental decline. Legislative processes, however, have often been delayed and the effectiveness of the laws trimmed by the strong industrial lobby. The erratic developments in the 1980s nevertheless allowed the enactment of four dedicated environmental laws and a complement of ancillary control measures. The current status of the environment in the fields of water, waste, air and noise has been assessed to highlight the pertinent maladies and shortcomings. The 1989 White Paper provided a clear package of official policies and programmes to correct past ills in a ten-year comprehensive plan. The ameliorative measures, both present and projected, are evaluated for their effectiveness and prospects. Some issues that deserve more attention and improvements are suggested.     

Combustion sources of particles. 1. Health relevance and source signatures

Combustion processes result in generation of a large number of particle and gaseous products that create health and environmental risks. Of particular importance are the very small particles that are emitted in large quantities from all the combustion sources, and that have been shown to be potentially more significant in terms of their impact on health than larger particles. To control and mitigate the particles with a view of health and environmental risk reduction, a good understanding is necessary of the relative and absolute contribution from the emission sources to the airborne concentrations. This understanding could only be achieved by developing source signature libraries through direct emission measurements from the sources on one hand, and by measuring particle concentrations in the air, and apportioning them to the specific local and distant sources using the signatures, on the other hand. This paper is a review of particle characteristics that are used as source signatures as well as their general advantages and limitations. The second part of the paper reviews source signatures of the most common combustion pollution sources.     

Biomarker approach to evaluating the impact of scientific stations on the Antarctic environment using Trematomus bernacchii as a bioindicator organism

A biomonitoring study was performed to evaluate the human impact on two small coves adjacent to the Italian Scientific Station at Terra Nova Bay in November 1995. The study used the fish species Trematomus bernacchii as a bioindicator organism for a biomarker analysis based on porphyrin levels, and BPMO (Benzo(a)pyrene MonoOxygenase) and EROD (Ethoxyresorufin-O-deethylase) activities. Porphyrin levels and EROD and BPMO activities were found to be generally low. In contrast to previous years, no statistically significant difference was found between the potentially contaminated cove and the control cove after the Italian expedition had been active nearby for a period of one month. This indicates a marked decrease in certain types of contaminants such as organochlorines and trace metals, mainly due to improvements in waste disposal.     

Control of ozone precursors in a complex industrial terrain by using multiscale-nested air quality models with fine spatial resolution (1 km2)

The location of the northeastern Iberian Peninsula (NEIP) in the northwestern Mediterranean basin, the presence of the Pyrenees mountain range (with altitudes > 3000 m), and the influence of the Mediterranean Sea and the large valley canalization of Ebro river induce an extremely complicated structure for the dispersion of photochemical pollutants. Air pollution studies in very complex terrains such as the NEIP require high-resolution modeling for resolving the very complex dynamics of flows. To deal with the influence of larger-scale transport, however, high-resolution models have to be nested in larger models to generate appropriate initial and boundary conditions for the finer resolution domains. This article shows the results obtained through the utilization of the MM5-EMICAT2000-CMAQ multiscale-nested air quality model relating the sensitivity regimes for ozone (O3)-nitrogen oxides (NOx)-volatile organic compounds (VOCs) in an area of high geographical complexity, like the industrial area of Tarragona, located in the NEIP. The model was applied with fine temporal (one-hour) and spatial resolution (cells of 24 km, 2 km, and 1 km) to represent the chemistry and transport of tropospheric O3 and other photochemical species with respect to different hypothetical scenarios of emission controls and to quantify the influence of different emission sources in the area. Results indicate that O3 chemistry in the industrial domain of Tarragona is strongly sensitive to VOCs; the higher percentages of reduction for ground-level O3 are achieved when reducing by 25% the emissions of industrial VOCs. On the contrary, reductions in the industrial emissions of NOx contribute to a strong increase in hourly peak levels of O3. At the same time, the contribution of on-road traffic and biogenic emissions to ground-level O3 concentrations in the area is negligible with respect to the pervasive weight of industrial sources. This analysis provides an assessment of the effectiveness of different policies for the control of emission of precursors by comparing the modeled results for different scenarios.     

Combustion sources of particles: 2. Emission factors and measurement methods

Emissions from the combustion of biomass and fossil fuels are a significant source of particulate matter (PM) in ambient outdoor and/or indoor air. It is important to quantify PM emissions from combustion sources for regulatory and control purposes in relation to air quality. In this paper, we review emission factors for several types of important combustion sources: road transport, industrial facilities, small household combustion devices, environmental tobacco smoke, and vegetation burning. We also review current methods for measuring particle physical characteristics (mass and number concentrations) and principles of methodologies for measuring emission factors. The emission factors can be measured on a fuel-mass basis and/or a task basis. Fuel-mass based emission factors (e.g., g/kg of fuel) can be readily used for the development of emission inventories when the amount of fuels consumed are known. Task-based emission factors (g/mile driven, g/MJ generated) are more appropriate when used to conduct comparisons of air pollution potentials of different combustion devices. Finally, we discuss major shortcomings and limitations of current methods for measuring particle emissions and present recommendations for development of future measurement techniques.     

Use of O2 consumption and CO2 production in kinetic cells to delineate pyrite oxidation-carbonate buffering and microbial respiration in unsaturated media

Identifying zones of sulphide oxidation and carbonate buffering is important in the development of a management plan for mine waste-rock piles. In this study, we used a kinetic cell technique to measure rates of O2 consumption and CO2 production in low sulphide (<0.12 wt.% S), low inorganic carbon (<0.20 wt.% C(inorganic)), gneissic waste rock and associated organic-rich lake sediment (0.7 wt.% C(organic)), and forest soil (1.4 wt.% C(organic)) collected from the Key Lake uranium mine in Saskatchewan, Canada. Solid chemistry, stable carbon isotope, pore water sulphate concentration data, and stoichiometric considerations indicated that O2 consumption and CO2 production were constrained by microbial respiration in the lake sediment and forest soil and by pyrite oxidation-carbonate buffering in the gneissic waste rock. Mean ratios of molar CO2 production to O2 consumption rates were 0.5 for lake sediment, 0.7 for forest soil, and 0.2 for gneissic waste rock. The different O2/CO2 ratios suggested that O2-CO2 monitoring may provide a practical tool for identifying the zones of microbial respiration and pyrite oxidation-carbonate buffering in mine waste-rock piles. Rates of O2 consumption and CO2 production were about one order of magnitude greater in lake sediment than in gneissic waste rock, indicating that microbial respiration would exert a control on the distribution of O2 and CO2 gas in waste-rock piles constructed upon the dewatered lake sediments.     

Development of the IM147: an alternative inspection/maintenance mass-emission transient test to address vehicle preconditioning concerns

A series of studies was performed to develop an alternative to the U.S. Environmental Protection Agency's gold standard IM240 mass-based emission test. The new IM147 test was based on the second phase of the IM240 that consists of 147 sec of transient vehicle operation. Paired IM240/IM147 tests were conducted on vehicles ranging from 1981 to 1996 to determine IM147 cutpoints and excess emissions were identified. Additionally, an optimized test procedure was developed that combined possible triplicate IM147s with improved drive trace quality control, fast-pass, and retest methods. The optimized procedure was found to provide improved vehicle preconditioning with a relatively minor decrease in excess emissions identification. Resulting identification rates ranged from 96 to 100% for hydrocarbons (HC), 93-100% for CO, and 93-100% for NOx, depending on cutpoint selection, while false failures caused by lack of vehicle preconditioning were reduced to essentially zero. Significant vehicle throughput improvements were achieved through the development of software algorithms involving modal fast-pass and retest procedures. Modal drive trace variation limits also were developed to improve test accuracy. The combination of the algorithms reduced average IM147 test times by nearly 60%.