The decomposition of wood products in landfills in Sydney, Australia

Three landfill sites that had been closed for 19, 29 and 46 years and had been operated under different management systems were excavated in Sydney. The mean moisture content of the wood samples ranged from 41.6% to 66.8%. The wood products recovered were identified to species, and their carbon, cellulose, hemicellulose and lignin concentration were determined and compared to those of matched samples of the same species. No significant loss of dry mass was measured in wood products buried for 19 and 29 years, but where refuse had been buried for 46 years, the measured loss of carbon (as a percentage of dry biomass) was 8.7% for hardwoods and 9.1% for softwoods, equating to 18% and 17% of their original carbon content, respectively. The results indicate that published decomposition factors based on laboratory research significantly overestimate the decomposition of wood products in landfill.     

中国、印度和世界的新秩序《世界报告2006》第一章(续)

转向世界粮食市场 与严重依赖外国石油的状况形成鲜明对照的是,中国和印度如今在粮食方面处于自给自足的状态,并为它们的成就而自豪（图1-2）.这两个国家都经历过严重饥荒的困难历史,都不希望这一悲剧情况重演.自从1985年以来,中国进口的粮食从来没有超过其消费总量的6%,而印度进口的粮食也没有超过其消费总量的3%（表1-3）.但是,在未来的几十年内,这两个大国是否可以避免求助于全球粮食市场（主要指小麦、水稻、玉米和其他主要基本食品）,已成为这两个国家和全球的一个尚待解决的、重要的问题.这是由于：世界粮食市场与石油市场的状况一样,与20世纪比较,指望生产过剩已经远非那么可靠了.     

Biochemical genetic variation at a leucine aminopeptidase (LAP) locus in blue (Mytilus galloprovincialis) and greenshell (Perna canaliculus) mussel populations along a salinity gradient

In several marine bivalve species, biochemical genetic variation at a leucine aminopeptidase (LAP) locus is associated with environmental variability, primarily salinity fluctuation. Population genetic variation at a LAP locus was investigated here in two sympatric mussel species (Mytilus galloprovincialis and Perna canaliculus) from three locations along a salinity gradient in Wellington Harbour, New Zealand. The data for M. galloprovincialis and P. canaliculus do not support the hypothesis that the LAP polymorphism in either species is associated with salinity variation among adult mussels. Due to the absence of small mussels among the samples it is not possible to discount the hypothesis that selection acts primarily against juveniles, as it does for M. edulis in Long Island Sound, USA. Wellington Harbour populations of M. galloprovincialis exhibited large and often highly significant heterozygote excesses at the LAP locus, whereas populations of P. canaliculus from the same locations exhibited large and highly significant heterozygote deficiencies. The reason for this inter-specific difference in population structure is unknown. If it is the result of selection, this suggests that selection acts differentially upon the two species, because demographic attributes and reproductive biology are very similar in the two species. For both M. galloprovincialis and P. canaliculus, significant levels of population genetic heterogeneity were recorded among three locations separated by only 8 to 12 km. Neither species exhibited shell length-dependent genetic variation at the LAP locus, suggesting that for these two species the LAP polymorphism is not associated with variation in shell length. Received: 30 December 1996 / Accepted: 6 January 1997     

Genotype-dependent fecundity and temporal variation of spawning in hybrid mussel (Mytilus) populations

Mussel samples were collected at 4 to 6 wk intervals throughout 1987 from two hybridMytilus edulis/M. galloprovincialis populations, at Croyde Bay and Whitsand Bay, in southwest England. These were analyzed at two polymorphic loci which are diagnostic for allozyme differences which typifyM. edulis andM. galloprovincialis. Dry mantle weight as a function of shell length was determined for all individuals of each sample. Size-frequency data for the two populations was obtained in September 1987 and March 1988. For all genotypes at both sites, fecundity was a function of shell length, and in both populations the frequency ofM. galloprovincialis alleles was positively correlated with shell length. At both sites, allozyme genotype explained a significant amount of variation in mantle weight either when assessed as a main effect or when assessed as an interaction with shell length or time of collection. At Croyde,M. galloprovincialis mussels had greater estimated fecundity per unit length than theM. edulis mussels. Differences in the timing of spawning activity between theM. edulis and theM. galloprovincialis mussels were inferred, and these differences might act to reduce the amount of interbreeding at Croyde. At Whitsand, a reduced level of variability in the timing of spawning activity and fecundity between the genotypes was observed and explained by a higher degree of genetic mixing. Because theM. galloprovincialis mussels had (1) a greater estimated fecundity at any length, and (2) a greater mean length than theM. edulis mussels, the mean genotypic annual fecundity perM. galloprovincialis mussel was 2.8 times greater than an individualM. edulis mussel at Croyde, and 2.2 times greater than an individualM. edulis mussel at Whitsand. This evidence thatM. galloprovincialis mussels have an advantage in fecundity, and thus perhaps in fertility, taken together with the evidence thatM. galloprovincialis also has a higher viability, indicates directional selection in favour of theM. galloprovincialis phenotype. Because of the observed temporal stability of the population it seems likely that this selection is counterbalanced by a massive imigration ofM. edulis spat from neighbouring populations.     

Polycyclic aromatic hydrocarbons in sediments and associated benthos in Lake Erie

Polycyclic aromatic hydrocarbons (PAH) were analyzed in surficial sediments and benthic organisms in southwestern Lake Erie near a large coal fired power plant. Sediment concentrations (530–770 ppb PAH) were relatively homogenous throughout most of the 150 km² area, although river and nearshore concentrations reached nearly 4 ppm. Oligochaete worms and chironomid midges were near equilibrium with local sediments except for enhanced concentrations in nearshore midges.     

Thresholds of species loss in Amazonian deforestation frontier landscapes

In the Brazilian Amazon, private land accounts for the majority of remaining native vegetation. Understanding how land‐use change affects the composition and distribution of biodiversity in farmlands is critical for improving conservation strategies in the face of rapid agricultural expansion. Working across an area exceeding 3 million ha in the southwestern state of Rondônia, we assessed how the extent and configuration of remnant forest in replicate 10,000‐ha landscapes has affected the occurrence of a suite of Amazonian mammals and birds. In each of 31 landscapes, we used field sampling and semistructured interviews with landowners to determine the presence of 28 large and medium sized mammals and birds, as well as a further 7 understory birds. We then combined results of field surveys and interviews with a probabilistic model of deforestation. We found strong evidence for a threshold response of sampled biodiversity to landscape level forest cover; landscapes with <30–40% forest cover hosted markedly fewer species. Results from field surveys and interviews yielded similar thresholds. These results imply that in partially deforested landscapes many species are susceptible to extirpation following relatively small additional reductions in forest area. In the model of deforestation by 2030 the number of 10,000‐ha landscapes under a conservative threshold of 43% forest cover almost doubled, such that only 22% of landscapes would likely to be able to sustain at least 75% of the 35 focal species we sampled. Brazilian law requires rural property owners in the Amazon to retain 80% forest cover, although this is rarely achieved. Prioritizing efforts to ensure that entire landscapes, rather than individual farms, retain at least 50% forest cover may help safeguard native biodiversity in private forest reserves in the Amazon. Umbrales de Pérdida de Especies en los Paisajes Fronterizos de Deforestación en el Amazonas Ochoa‐Quintero     

Community acceptance of policy options for managing the maintenance of rainwater tanks

This research examined community acceptance of policy instruments that could be used to promote ongoing maintenance of domestic rainwater tank systems. Using an online survey of 533 tank owners in South East Queensland, Australia, the research investigated four sets of factors that influence policy acceptance: features of the policy, judgements of policy fairness and effectiveness, contextual framing, and individual attitudes and motivations towards tank maintenance. An experimental design incorporating choice modelling was employed. Results demonstrated that perceptions of policy fairness and effectiveness are important to acceptance. Policies that include enabling features associate with increased perceptions of effectiveness, and policies that use incentives are linked to increased perceptions of both fairness and effectiveness. Individual attitudes and motivations regarding tank maintenance were significant predictors of policy support. Perceptions of a person's own ability to undertake tank maintenance tasks were negative predictors of policy intervention, suggesting that people who believe they can carry out maintenance themselves may not see the need for a policy that encourages tank maintenance to exist. The findings are discussed in relation to issues of policy design.     

Artificial Neural Network-Derived Trends in Daily Maximum Surface Ozone Concentrations

ABSTRACT

Interannual variability in meteorological conditions can confound attempts to identify changes in ozone concentrations driven by reduced precursor emissions. In this paper, a technique is described that attempts to maximize the removal of meteorological variability from a daily maximum ozone time series, thereby revealing longer term changes in ozone concentrations with increased confidence. The technique employs artificial neural network [multilayer perceptron (MLP)] models, and is shown to remove more of the meteorological variability from U.S. ozone data than does a Kolmogorov-Zurbenko (KZ) filter and conventional regression-based technique.     

Ecology and conservation of the rare annual Petrorhagia nanteuilii (Childing Pink) on the vegetated shingle spits of Pagham Harbour, West Sussex

Petrorhagia nanteuilii (Childing Pink), a nationally rare annual, exists at only one location in the UK on the vegetated shingle spits at Pagham Harbour, West Sussex. Primarily found in dry grassland habitats throughout Spain and Portugal, at present its only known threat in the UK is the invasive perennial, Centranthus ruber (Red Valerian); however for conservation of Petrorhagia nanteuilii to be sustainable, its presence at Pagham Harbour must be better understood. The aim of this study was therefore to investigate the local distribution and ecological associations of Petrorhagia nanteuilii in order to understand the relationships between Petrorhagia nanteuilii and the vegetated shingle communities and thereby inform their conservation. Field surveys of the shingle flora were undertaken in 2007 and 2011. Vegetation was sampled and the edaphic and physical environment was also investigated using TWINSPAN, multivariate analyses and GIS. The results of the study show that Petrorhagia nanteuilii has little association with the true vegetated shingle communities on the shingle spits. They also reveal that in recent years the species has spread rapidly across parts of the site due to a number of adaptations aiding its survival and recent shifts in conservation management that have influenced spit morphology. The ecological disconnection that exists between Petrorhagia nanteuilii and the true shingle communities means it is unlikely that management strategies will be conflicting. The study concludes that conservation of both is feasible, however for management to be sustainable, both short-term and long-term strategies must be considered.     

Parameter constraints in a stream ecosystem model: Incorporation of a priori information in Monte Carlo error analysis

Using a model of mass and nutrient dynamics in a stream, we evaluated the use of a priori information (e.g., mass balance constraints, limits for the state variables, etc.) to increase the accuracy and efficiency of Monte Carlo error analysis. The results indicated that a priori information can effectively eliminate physically unrealistic simulations and reduce uncertainty about the predicted values. Some types of a priori information proved more helpful than increased accuracy in measuring model parameters.