Changes in Size of Deforested Patches in the Brazilian Amazon

Abstract: Different deforestation agents, such as small farmers and large agricultural businesses, create different spatial patterns of deforestation. We analyzed the proportion of deforestation associated with different‐sized clearings in the Brazilian Amazon from 2002 through 2009. We used annual deforestation maps to determine total area deforested and the size distribution of deforested patches per year. The size distribution of deforested areas changed over time in a consistent, directional manner. Large clearings (>1000 ha) comprised progressively smaller amounts of total annual deforestation. The number of smaller clearings (6.25–50.00 ha) remained unchanged over time. Small clearings accounted for 73% of all deforestation in 2009, up from 30% in 2002, whereas the proportion of deforestation attributable to large clearings decreased from 13% to 3% between 2002 and 2009. Large clearings were concentrated in Mato Grosso, but also occurred in eastern Pará and in Rondônia. In 2002 large clearings accounted for 17%, 15%, and 10% of all deforestation in Mato Grosso, Pará, and Rondônia, respectively. Even in these states, where there is a highly developed agricultural business dominated by soybean production and cattle ranching, the proportional contribution of large clearings to total deforestation declined. By 2009 large clearings accounted for 2.5%, 3.5%, and 1% of all deforestation in Mato Grosso, Pará, and Rondônia, respectively. These changes in deforestation patch size are coincident with the implementation of new conservation policies by the Brazilian government, which suggests that these policies are not effectively reducing the number of small clearings in primary forest, whether these are caused by large landholders or smallholders, but have been more effective at reducing the frequency of larger clearings.     

Practical Applications of Stacks to Minimize Pollution Problems

“Rules of thumb” for stack design have been developed for use on problems where extensive studies cannot be justified or where quantitative design data are unavailable. The application of these rules to a practical stack design problem is discussed. The IBM 704 computer has been used for rapid yet rigorous stack design studies. The computer procedures for design are discussed and its application to a practical problem is described in detail.     

Investigation of the concentration and isotopic composition of inputs and outputs of Pb in waters at an upland catchment in NE Scotland

As a consequence of the accumulation of anthropogenic Pb in upland catchments, there has been much recent concern about the potential mobilisation and transport of Pb from the soils to receiving waters and also the possible harmful effects that this might have on aquatic biota. This paper presents the findings of a two-year study of Pb behaviour in an organic-rich upland catchment at Glensaugh in NE Scotland. Pb inputs to the catchment were characterised by direct measurements of Pb concentration and (206)Pb/(207)Pb ratios in rain water and interception. Pb outputs from the catchment were calculated from measurements on stream water samples taken from the two main streams, the Cairn Burn and Birnie Burn. The relative contribution of Pb from groundwater and throughflow, under different flow conditions (base flow and high flow), to stream waters was investigated via analysis of springs sourced from groundwater and of waters flowing through the various soil horizons (S (surface), A, B, C, and D), respectively. The outcome of intensive sampling and analysis over the two-year time period was that, even with marked reduction in Pb inputs over the past two decades, the catchment was still acting as a net sink for the current atmospheric deposition. Although the Pb isotopic signature for stream water is very similar to that for the contemporaneous rain water ((206)Pb/(207)Pb approximately 1.15-1.16), only a small portion of the rain water is transferred directly to stream water. Instead, the Pb input is transferred to the stream waters mainly via groundwater and it was also confirmed that the latter had a similar Pb isotopic signature. From the Pb isotopic measurements on throughflow waters, however, Pb being removed via the streams contained some previously deposited Pb, i.e. mobilisation of a small portion of soil-derived anthropogenic Pb was occurring. These findings are important not only with respect to the source/sink status of the catchment but also for calculation of the extent of retention of the current atmospheric Pb inputs, which must take account of the release of previously deposited Pb from the catchment soils, a process occurring mainly under high flow conditions.     

The spatial distribution of ammonia emitted from seabirds and its contribution to atmospheric nitrogen deposition in the UK

Simple bioenergetics models were used to derive annual nitrogen excretion rates of each seabird species occurring at colonies in the UK. These were combined with population distribution data and an estimated fraction of nitrogen volatilized to estimate the spatial distribution of NH₃ emissions from seabird colonies at a 1 km resolution. The effect of these emissions on atmospheric NH₃ concentrations and nitrogen deposition in the UK was assessed using the FRAME atmospheric chemistry and transport model. The total emission of NH₃ from the UK seabird colonies is estimated at 2.7 kt yr^?1. Emissions from seabirds are largely concentrated in remote parts of Britain, where agricultural and other anthropogenic emissions are minimal. Although seabirds account for less than 1% of total UK NH₃ emissions (～370 kt yr^?1), their occurrence in remote areas and frequently large colony sizes results in seabirds providing a major fraction of the atmospheric nitrogen deposition for many remote ecosystems.     

Long-Term Growth Enhancement of Baldcypress (Taxodium distichum) from Municipal Wastewater Application

Taxodium distichum (L.) Rich.]. The study site, a swamp in St. Martin Parish, Louisiana, has received municipal wastewater for the last 40 years. Growth chronologies from 1920 to 1992 were developed from cross-dated tree core samples taken from treated and control sites with similar size and age classes. Mean diameter increment (DINC) and mean basal area increment (BAI) chronologies were constructed separately for each stand. These chronologies were then summarized by tree and stand into seven nine-year intervals resulting in three pretreatment intervals from 1926 to 1952 and four treatment intervals from 1953 to 1988. Significant differences in growth response between sites showed a consistent pattern of growth enhancement in the treated site coincident with the onset of effluent discharge. The ratio of treated to control baldcypress growth rates (computed from DINC) averaged 0.74 during the pretreatment period and 1.53 during the treatment period. Over the period of study, control DINC decreased from 77 mm to 29 mm/nine-year interval, while treatment DINC increased slightly from 40 mm to 47 mm/nine-year interval. Control BAI did not increase significantly and averaged 192 cm²/nine-year interval. There was a significant increase in treatment BAI from 129 to 333 cm²/nine-year interval over the period of record. These results clearly demonstrate sustained long-term baldcypress growth enhancement throughout 40 years of municipal effluent discharge.     

The importance of the short-term leaching dynamics of wood preservatives

The potential environmental impacts from the use of treated timber in aquatic areas is under scrutiny as a result of environmental legislation and reports of the deleterious environmental effects around treated structures. In this study leaching experiments of up to 3 weeks duration were conducted on two species of chromated copper arsenate treated timber, dried for different periods of time. Increased drying time significantly reduced leaching of Cr and As. The addition of a synthetic humic acid increased leaching of Cu and As, but reduced leaching of Cr. Putative risk assessments conducted using short-term copper leaching data suggested protocol design may influence decisions made regarding the environmental acceptability of such preservatives.     

The Status and Conservation of the Wolf in Gujarat and Rajasthan, India

Abstract: Populations of wolves were estimated for the states of Gujarat and Rajasthan, India, based on interviews and surveys. The wolf range is continuous. The total number of wolves in Gujarat is between 190 and 270 and in Rajasthan is between 253 and 350. Recommendations for a wolf conservation strategy include: (1) encouraging public support and education, (2) enforcing legal protection, (3) paying compensation for wolf-killed livestock, (4) conducting surveys of wolf populations and research on the dynamics of select populations, (5) protecting breeding habitats, and (6) eradicating feral dogs from wolf conservation areas. It is not too late to save the wolf if such a conservation strategy is implemented immediately.     

The spatial distribution of ammonia emitted from seabirds and its contribution to atmospheric nitrogen deposition in the UK

Simple bioenergetics models were used to derive annual nitrogen excretion rates of each seabird species occurring at colonies in the UK. These were combined with population distribution data and an estimated fraction of nitrogen volatilized to estimate the spatial distribution of NH₃ emissions from seabird colonies at a 1 km resolution. The effect of these emissions on atmospheric NH₃ concentrations and nitrogen deposition in the UK was assessed using the FRAME atmospheric chemistry and transport model. The total emission of NH₃ from the UK seabird colonies is estimated at 2.7 kt yr^–1. Emissions from seabirds are largely concentrated in remote parts of Britain, where agricultural and other anthropogenic emissions are minimal. Although seabirds account for less than 1% of total UK NH₃ emissions (370 kt yr^–1), their occurrence in remote areas and frequently large colony sizes results in seabirds providing a major fraction of the atmospheric nitrogen deposition for many remote ecosystems.     

Worldwide Availability of Silver

This article summarizes and interprets estimates, by the US Bureau of Mines and others, of the availability of silver from primary and secondary sources in market economy countries. Despite conservative measurements, ample silver to support expansion of its use in industrial applications was found to exist. Supply from only portions of this resource base can be expected to respond to changes in silver demand, because factors other than price are the major determinant of the flow of silver from large segments of its resource base.