Improving marine water quality by mussel farming: a profitable solution for Swedish society

Eutrophication of coastal waters is a serious environmental problem with high costs for society globally. In eastern Skagerrak, reductions in eutrophication are planned through reduction of nitrogen inputs, but it is unclear how this can be achieved. One possible method is the cultivation of filter-feeding organisms, such as blue mussels, which remove nitrogen while generating seafood, fodder and agricultural fertilizer, thus recycling nutrients from sea to land. The expected effect of mussel farming on nitrogen cycling was modeled for the Gullmar Fjord on the Swedish west coast and it is shown that the net transport of nitrogen (sum of dissolved and particulate) at the fjord mouth was reduced by 20%. Existing commercial mussel farms already perform this service for free, but the benefits to society could be far greater. We suggest that rather than paying mussel farmers for their work that nutrient trading systems are introduced to improve coastal waters. In this context an alternative to nitrogen reduction in the sewage treatment plant in Lysekil community through mussel farming is presented. Accumulation of bio-toxins has been identified as the largest impediment to further expansion of commercial mussel farming in Sweden, but the problem seems to be manageable through new techniques and management strategies. On the basis of existing and potential regulations and payments, possible win-win solutions are suggested.     

Genetic Criteria for Establishing Evolutionarily Significant Units in Cryan's Buckmoth

Buckmoths ( Hemileuca spp.) are day-flying saturniid moths with diverse ecologies and host plants. Populations that feed on Menyanthes trifoliata , known commonly as Cryan's buckmoths, have been found in only a few bogs and fens near eastern Lake Ontario in New York and near Ottawa in Ontario, Canada. Because of their unique ecological traits, geographic isolation from other Hemileuca populations, and the small number of sites they occupy, there is concern that the Cryan's buckmoth populations are phylogenetically distinct and should be protected. The Cryan's buckmoths have not yet been taxonomically described and do not appear to have clear distinguishing morphological characters. Both molecular genetic traits (allozymes and mitochondrial DNA sequences) and an ecologically based character (host performance) were investigated to determine whether these populations possess fixed diagnostic characters signifying genetic differentiation from other eastern Hemileuca populations. Such differences would merit separate conservation management as an evolutionarily significant unit. Our studies showed that the Cryan's buckmoths clearly belong to the Hemileuca maia species group, but they could not be readily distinguished from other members of that group by means of molecular genetic techniques. There were no fixed differences in alleles or haplotypes distinguishing any of the populations or species, suggesting recent divergence. Nonetheless, in the host-plant performance experiment only the Cryan's buckmoth larvae were able to develop on M. trifoliata , a significant difference from other Hemileuca larvae tested. The Cryan's buckmoth appears to be unique in host performance and warrants protection and management us an evolutionarily significant unit. In cases such as this where groups appear to have recently diverged, investigations into ecologically significant traits may provide indicators of conservation significance as reliable as molecular genetic markers.     

A greenhouse gas emissions inventory for Pennsylvania

The Pennsylvania greenhouse gas (GHG) emissions inventory presented in this paper provides detailed estimates of emissions and their sources for the six major categories of GHGs. The inventory was compiled using the current U.S. Environment Protection Agency methodology, which applies emissions factors to socioeconomic data, such as fossil energy use, vehicle miles traveled, and industrial production. The paper also contains an assessment of the methodology and suggestions for improving accounting with respect to process, sectoral, and geographic considerations. The study found that Pennsylvania emitted 77.4 million metric tons carbon equivalent of GHGs in 1990 and that this total increased by 3% to 79.8 million metric tons carbon equivalent by 1999. Despite this increase, however, the state's percentage contribution to the United States total declined during the decade. Pennsylvania's carbon dioxide (CO2) emissions from fossil fuels represented 92.4% of 1990 totals and declined to 90.5% in 1999. Electricity generation was the largest single source of CO2 emissions, being responsible for 38% of fossil fuel CO2 emissions in 1990 and 40% of the total in 1999. Transportation emissions accounted for the largest increases in emissions between 1990 and 1999, whereas industrial emissions accounted for the largest decrease. The overall trend indicates that Pennsylvania has been able to weaken the relationship between GHG emissions and economic growth.     

Predicting tree distributions in an East African biodiversity hotspot: model selection, data bias and envelope uncertainty

The Eastern Arc Mountains (EAMs) of Tanzania and Kenya support some of the most ancient tropical rainforest on Earth. The forests are a global priority for biodiversity conservation and provide vital resources to the Tanzanian population. Here, we make a first attempt to predict the spatial distribution of 40 EAM tree species, using generalised additive models, plot data and environmental predictor maps at sub 1 km resolution. The results of three modelling experiments are presented, investigating predictions obtained by (1) two different procedures for the stepwise selection of predictors, (2) down-weighting absence data, and (3) incorporating an autocovariate term to describe fine-scale spatial aggregation. In response to recent concerns regarding the extrapolation of model predictions beyond the restricted environmental range of training data, we also demonstrate a novel graphical tool for quantifying envelope uncertainty in restricted range niche-based models (envelope uncertainty maps). We find that even for species with very few documented occurrences useful estimates of distribution can be achieved. Initiating selection with a null model is found to be useful for explanatory purposes, while beginning with a full predictor set can over-fit the data. We show that a simple multimodel average of these two best-model predictions yields a superior compromise between generality and precision (parsimony). Down-weighting absences shifts the balance of errors in favour of higher sensitivity, reducing the number of serious mistakes (i.e., falsely predicted absences); however, response functions are more complex, exacerbating uncertainty in larger models. Spatial autocovariates help describe fine-scale patterns of occurrence and significantly improve explained deviance, though if important environmental constraints are omitted then model stability and explanatory power can be compromised. We conclude that the best modelling practice is contingent both on the intentions of the analyst (explanation or prediction) and on the quality of distribution data; generalised additive models have potential to provide valuable information for conservation in the EAMs, but methods must be carefully considered, particularly if occurrence data are scarce. Full results and details of all species models are supplied in an online Appendix.     

Is risk-sharing resource taxation in society's best interests if prices are log-normally distributed?

This paper contributes to our understanding of the perceived benefits for society of risk-sharing resource taxation. In the particular context of log-normally distributed prices a model is developed which enables comparison of risk-sharing resource taxation with an alternative in determining the overall return to society from auctioning an extraction lease. The main finding of the paper is a potential exception to the general preference for risk-sharing resource taxation if the bidding firms are effectively risk neutral. This exception is illustrated numerically in the context of the impact of increased price uncertainty, but it is shown not to be robust with respect to divergences from risk neutrality in the risk attitudes of firms. Consequently, it is concluded that the choice of risk-sharing resource taxation is likely to be in society's best interests, regardless of the probability distribution of prices.     

Availability and leaching of polycyclic aromatic hydrocarbons: Controlling processes and comparison of testing methods

We have studied the availability and leaching of polycyclic aromatic hydrocarbons (PAHs) from two contaminated materials, a tar-containing asphalt granulate (Sigma16 US-EPA PAHs 3412mg/kg) and gasworks soil (SigmaPAHs 900mg/kg), by comparing results from three typical types of leaching tests: a column, sequential batch, and two different availability tests. The sequential batch test was found to largely resemble the column test. However, the leaching of particularly the larger PAHs (>5 aromatic rings) was found to be enhanced in the batch test by up to an order of magnitude, probably due to their association with large DOC (dissolved organic carbon) molecules generated by the vigorous mixing. The release of PAHs in the two availability tests, in which the leaching is facilitated by either a high concentration of DOC or Tenax resin, was similar, although the latter test was easier to perform and yielded more repeatable results. The availability was much higher than the amount leached in the column and sequential batch tests. However, biodegradation had apparently occurred in the column test and the total amount of PAHs released by either leaching or biodegradation, 9% and 26% for asphalt granulate and gasworks soil, respectively, did equal the amount leached in the availability tests. Therefore, the availability was found to provide a relevant measure of the PAH fraction that can be released from the solid phase. These results stress the importance of using the available instead of the total amount of contaminant in the risk analysis of solid materials in utilization or disposal.     

Following Old Paths or Shaping New Ones in Natura 2000 Implementation? Mapping Path Dependency in Instrument Choice

This article reviews the influence of two specific European Union (EU) laws, the Birds and Habitats Directives, on the choice of national policy instruments by Member States. Both Directives leave the choice for policy instruments to manage the sites designated under the Directives to the Member States. Using path dependency as a leading concept, this article analyses the continuity or changes in policy instruments due to the implementation of the Directives in 15 countries. This article shows that the tendency to use existing instruments to implement EU policy is limited, as in almost all countries new instruments were developed. Yet, states do tend to choose instruments from their predominant policy instrument mix and preferred implementation style to address the management requirements of the Directives. Additionally, in Central and Eastern European countries where the implementation of EU policy coincided with a process of transition to a market economy, new instruments were introduced outside the existing implementation style. The introduction of new policy instruments is the result of historical turns, domestic pressure and a shift to new modes of governance. National case studies are needed to shed more light on the interaction between EU policy and domestic factors during the process of instrument choice.     

Upscaling of business model experiments in off-grid PV solar energy in India

Rapidly developing countries like India face numerous challenges related to social and environmental sustainability, which are associated with their fast economic growth and rising energy demand, climate change, and widening disparities between the rich and the poor. Recently, a number of claims have been made in the literature that the prospects of alternative development pathways in emerging economies in Asia are becoming more likely, and that these economies might even leapfrog Western initiatives. This paper contributes by reporting on the five most visible and established initiatives in the area of off-grid PV solar energy in India, specifically homing in on the innovative business models that are evolving. We develop a new typology of upscaling dimensions in order to analyze these five initiatives. They are found to be quite successful, but have difficulty in terms of reaching the poorest of the poor (deep upscaling) and bringing about required institutional change (institutional upscaling).