Amazonian Tree Mortality during the 1997 El Niño Drought

Abstract: In 1997, the Amazon Basin experienced an exceptionally severe El Niño drought. We assessed effects of this rare event on mortality rates of trees in intact rain forest based on data from permanent plots. Long-term (5- to 13-year) mortality rates averaged only 1.12% per year prior to the drought. During the drought year, annual mortality jumped to 1.91% but abruptly fell back to 1.23% in the year following El Niño. Trees dying during the drought did not differ significantly in size or species composition from those that died previously, and there was no detectable effect of soil texture on mortality rates. These results suggest that intact Amazonian rainforests are relatively resistant to severe El Niño events.     

Restoration planning to guide Aichi targets in a megadiverse country

Ecological restoration has become an important strategy to conserve biodiversity and ecosystems services. To restore 15% of degraded ecosystems as stipulated by the Convention on Biological Diversity Aichi target 15, we developed a prioritization framework to identify potential priority sites for restoration in Mexico, a megadiverse country. We used the most current biological and environmental data on Mexico to assess areas of biological importance and restoration feasibility at national scale and engaged stakeholders and experts throughout the process. We integrated 8 criteria into 2 components (i.e., biological importance and restoration feasibility) in a spatial multicriteria analysis and generated 11 scenarios to test the effect of assigning different component weights. The priority restoration sites were distributed across all terrestrial ecosystems of Mexico; 64.1% were in degraded natural vegetation and 6% were in protected areas. Our results provide a spatial guide to where restoration could enhance the persistence of species of conservation concern and vulnerable ecosystems while maximizing the likelihood of restoration success. Such spatial prioritization is a first step in informing policy makers and restoration planners where to focus local and large‐scale restoration efforts, which should additionally incorporate social and monetary cost–benefit considerations.     

Female choice over short and long distances: neighbour effects

Fiddler crabs live at high densities and mate-searching females encounter many males at varying distances. Who is the ideal neighbour for a male? There could be a trade-off if having neighbours that invest more in sexual signals increases the rate at which females initially move towards a focal male, but thereafter decrease the likelihood that he is chosen rather than his neighbour. We used robotic crabs to test whether female choice for focal males (identical claw size/courtship wave rate) varied depending on the relative investment in sexual signals of their two neighbours and the distance at which she first saw the males. The neighbours’ phenotype did not affect which of two focal males she initially approached from long-range (50 cm). When a female initially saw a trio of males at a close-range (20 cm), she preferentially chose the focal male over neighbours that invested less in sexual signals (smaller claw/slower wave rate), but did not show a preference for the focal male over neighbours that invested more in sexual signals (larger claw/faster wave rate). However, a female that started to approach a focal male with neighbours that invest more in sexual signals from 50 cm was significantly less likely to choose the focal male than when she first saw the trio at 20 cm. Our results suggest that the initial distance at which males are seen partly determines how neighbours’ sexual signals affect male mating success. In general, if larger males can retain smaller neighbours they might therefore increase their mating success.     

An analysis of variables influencing the material composition of automobiles

The use of materials is studied broadly, because of the environmental problems related to extraction, production, consumption and waste treatment. The use and substitution of materials in products is therefore a relevant issue for environmental policy making. Studies have been done to describe the material flow or to measure the impact of materials or products on the environment. However, these studies do not often consider economic, substitution and dynamic aspects of material flows. Other studies on material flows analyse the relationship between the use of materials and economic growth, but they do not consider substitution between materials. For environmental policy making economic, technological and environmental aspects of the use of materials need to be considered. Especially, substitution of materials is important. In various countries material and product policies are imposed on a variety of materials and products. For evaluation of these policies their environmental and economic effects need to be examined in detail. This study aims to analyse the economic and technological factors influencing the use of materials and the substitution between different materials dynamically. The goal is to obtain an insight in the effect that material levies may have on the use and substitution of materials. The statistical analysis is performed on a specific product-group because decisions on the use of materials are taken on a product-level. The case study is performed on automobiles. The results show that the material use is largely an autonomous development. The price of aluminium has a positive, significant effect on the use of that material. The price of plastics has a positive, but not significant effect on the use of plastics. Reasons may be that the costs of a raw material are small relative to the processing costs, and that the production process can only be changed slowly. Other factors, like competitiveness and consumers' tastes, may be more important for substitution. This implies that levies or subsidies on certain materials is not a promising policy to change the use of materials. Besides time, there are two other factors that have a positive and significant relationship with the use of aluminium and plastics: the fuel efficiency, which is the distance driven divided by the energy used; and, the road tax, which depends on the weight of a car. However, these effects are caused by their positive relationship with time. The main conclusion of the case study is that imposing a levy on materials may not have the desired or expected effect of reduction in material use.     

Comparing the effectiveness of education and technology in reducing wood smoke pollution: A field experiment

This study describes a field experiment assessing the effectiveness of education and technological innovation in reducing air pollution generated by domestic wood heaters. Two-hundred and twenty four households from a small regional center in Australia were randomly assigned to one of four experimental conditions: (1) Education only – households received a wood smoke reduction education pack containing information about the negative health impacts of wood smoke pollution, and advice about wood heater operation and firewood management; (2) SmartBurn only – households received a SmartBurn canister designed to improve combustion and help wood fires burn more efficiently, (3) Education and SmartBurn, and (4) neither Education nor SmartBurn (control). Analysis of covariance, controlling for pre-intervention household wood smoke emissions, wood moisture content, and wood heater age, revealed that education and SmartBurn were both associated with significant reduction in wood smoke emissions during the post-intervention period. Follow-up mediation analyses indicated that education reduced emissions by improving wood heater operation practices, but not by increasing health risk perceptions. As predicted, SmartBurn exerted a direct effect on emission levels, unmediated by wood heater operation practices or health risk perceptions.     

The potential leaching and mobilization of trace elements from FGD-gypsum of a coal-fired power plant under water re-circulation conditions

Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation (FGD)-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the pH and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the pH value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO₂SO₄, H₂Se, and HAsO₂ are the aqueous complexes with the highest activities under acidic conditions. The speciation of Zn, Li, and Ni is not affected in spite of pH changes; these elements occur as free cations and associated to SO₄² in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the pH of the FGD-gypsum leachates, which might be associated to the precipitation of CuSe₂ and MoSe₂, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples.     

The potential leaching and mobilization of trace elements from FGD-gypsum of a coal-fired power plant under water re-circulation conditions

Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation (FGD)-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the pH and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the pH value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO₂SO₄, H₂Se, and HAsO₂ are the aqueous complexes with the highest activities under acidic conditions. The speciation of Zn, Li, and Ni is not affected in spite of pH changes; these elements occur as free cations and associated to SO₄ ² in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the pH of the FGD-gypsum leachates, which might be associated to the precipitation of CuSe₂ and MoSe₂, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples.     

Evaluating Terrestrial Carbon Sequestration Options for Virginia

Changes in forest and agricultural land management practices have the potential to increase carbon (C) storage by terrestrial systems, thus offsetting C emissions to the atmosphere from energy production. This study assesses that potential for three terrestrial management practices within the state of Virginia, USA: afforestation of marginal agricultural lands; afforestation of riparian agricultural lands; and changing tillage practices for row crops; each was evaluated on a statewide basis and for seven regions within the state. Lands eligible for each practice were identified, and the C storage potential of each practice on those lands was estimated through a modeling procedure that utilized land-resource characteristics represented in Geographic Information System databases. Marginal agricultural lands’ afforestation was found to have the greatest potential (1.4 Tg C yr⁻¹, on average, over the first 20 years) if applied on all eligible lands, followed by riparian afforestation (0.2 Tg C yr⁻¹ over 20 years) and tillage conversion (0.1 Tg C yr⁻¹ over 14 years). The regions with the largest potentials are the Ridge and Valley of western Virginia (due to extensive areas of steep, shallow soils) and in the Mid-Atlantic Coastal Plain in eastern Virginia (wet soils). Although widespread and rapid implementation of the three modeled practices could be expected to offset only about 3.4% of Virginia’s energy-related CO₂ emissions over the following 20 years (equivalent to about 8.5% of a Kyoto Treaty–based target), they could contribute to achievement of C-management goals if implemented along with other mitigation measures.     

Adverse health effects of outdoor air pollutants

Much research on the health effects of outdoor air pollution has been published in the last decade. The goal of this review is to concisely summarize a wide range of the recent research on health effects of many types of outdoor air pollution. A review of the health effects of major outdoor air pollutants including particulates, carbon monoxide, sulfur and nitrogen oxides, acid gases, metals, volatile organics, solvents, pesticides, radiation and bioaerosols is presented. Numerous studies have linked atmospheric pollutants to many types of health problems of many body systems including the respiratory, cardiovascular, immunological, hematological, neurological and reproductive/ developmental systems. Some studies have found increases in respiratory and cardiovascular problems at outdoor pollutant levels well below standards set by such agencies as the US EPA and WHO. Air pollution is associated with large increases in medical expenses, morbidity and is estimated to cause about 800,000 annual premature deaths worldwide [Cohen, A.J., Ross Alexander, H., Ostro, B., Pandey, K.D., Kryzanowski, M., Kunzail, N., et al., 2005. The global burden of disease due to outdoor air pollution. J Toxicol Environ Health A. 68: 1-7.]. Further research on the health effects of air pollution and air pollutant abatement methods should be very helpful to physicians, public health officials, industrialists, politicians and the general public.