Implications of different population model structures for management of threatened plants

Population viability analysis (PVA) is a reliable tool for ranking management options for a range of species despite parameter uncertainty. No one has yet investigated whether this holds true for model uncertainty for species with complex life histories and for responses to multiple threats. We tested whether a range of model structures yielded similar rankings of management and threat scenarios for 2 plant species with complex postfire responses. We examined 2 contrasting species from different plant functional types: an obligate seeding shrub and a facultative resprouting shrub. We exposed each to altered fire regimes and an additional, species‐specific threat. Long‐term demographic data sets were used to construct an individual‐based model (IBM), a complex stage‐based model, and a simple matrix model that subsumes all life stages into 2 or 3 stages. Agreement across models was good under some scenarios and poor under others. Results from the simple and complex matrix models were more similar to each other than to the IBM. Results were robust across models when dominant threats are considered but were less so for smaller effects. Robustness also broke down as the scenarios deviated from baseline conditions, likely the result of a number of factors related to the complexity of the species’ life history and how it was represented in a model. Although PVA can be an invaluable tool for integrating data and understanding species’ responses to threats and management strategies, this is best achieved in the context of decision support for adaptive management alongside multiple lines of evidence and expert critique of model construction and output.     

Leaching behaviour of different scrap materials at recovery and recycling companies: Full-, pilot- and lab-scale investigation

Scrap material recovery and recycling companies are confronted with waste water that has a highly fluctuating flow rate and composition. Common pollutants, such as COD, nutrients and suspended solids, potentially toxic metals, polyaromatic hydrocarbons and poly chlorinated biphenyls can exceed the discharge limits. An analysis of the leaching behaviour of different scrap materials and scrap yard sweepings was performed at full-scale, pilot-scale and lab-scale in order to find possible preventive solutions for this waste water problem. The results of these leaching tests (with concentrations that frequently exceeded the Flemish discharge limits) showed the importance of regular sweeping campaigns at the company, leak proof or covered storage of specific scrap materials and oil/water separation on particular leachates. The particulate versus dissolved fraction was also studied for the pollutants. For example, up to 98% of the polyaromatic hydrocarbons, poly chlorinated biphenyls and some metals were in the particulate form. This confirms the (potential) applicability of sedimentation and filtration techniques for the treatment of the majority of the leachates, and as such the rainwater run-off as a whole.     

Defining and Evaluating the Umbrella Species Concept for Conserving and Restoring Landscape Connectivity

Conserving or restoring landscape connectivity between patches of breeding habitat is a common strategy to protect threatened species from habitat fragmentation. By managing connectivity for some species, usually charismatic vertebrates, it is often assumed that these species will serve as conservation umbrellas for other species. We tested this assumption by developing a quantitative method to measure overlap in dispersal habitat of 3 threatened species—a bird (the umbrella), a butterfly, and a frog—inhabiting the same fragmented landscape. Dispersal habitat was determined with Circuitscape, which was parameterized with movement data collected for each species. Despite differences in natural history and breeding habitat, we found substantial overlap in the spatial distributions of areas important for dispersal of this suite of taxa. However, the intuitive umbrella species (the bird) did not have the highest overlap with other species in terms of the areas that supported connectivity. Nevertheless, we contend that when there are no irreconcilable differences between the dispersal habitats of species that cohabitate on the landscape, managing for umbrella species can help conserve or restore connectivity simultaneously for multiple threatened species with different habitat requirements. Definición y Evaluación del Concepto de Especie Paraguas para Conservar y Restaurar la Conectividad de Paisajes     

Growth in urban extent and allometric analysis of West African cities

Urban area expansion is happening at much faster rates in Asian and African cities than elsewhere in the world. This study uses multi-temporal Landsat images to map the urban extent of six small to large cities in West Africa at four different time steps from the early 1970s–2010. The selected cities are Kumasi of Ghana, Daloa of Cote d’Ivoire, Abuja and Kano in Nigeria, Kindia of Guinea, and Ouagadougou of Burkina Faso. All cities revealed significant urban growth in both urban area and population; however, it was apparent that there was a lot of variability in urban area development. Exponential urban growth rates in the cities were measured as ranging between 0.026 and 0.077, with allometric scaling factors matching those of other countries.     

Effects of benzo[a]pyrene as an environmental pollutant and two natural antioxidants on biomarkers of reproductive dysfunction in male rats

Benzo[a]pyrene (B[a]P) is an environmental toxicant and endocrine disruptor. Therefore, the aim of the present study was to investigate the toxicity of B[a]P in testis of rats and also to study the role of silymarin and thymoquinone (TQ) as natural antioxidants in the alleviation of such toxicity. Data of the present study showed that levels of testosterone, estrogen and progesterone were significantly decreased after treatment of rats with B[a]P. In addition, B[a]P caused downregulation of the expressions of steroidogenic enzymes including CYP17A1 and CP19A1, and decreased the activity of 17-β hydroxysteroid dehydrogenase (17β-HSD). Moreover, B[a]P decreased the activities of antioxidant enzymes including catalase (CAT), glutathione peroxidase (GP_X) and superoxide dismutase (SOD), and significantly increased free radicals levels in testis of male rats. However, pretreatment of rats with silymarin prior to administration of B[a]P was found to restore the level of free radicals, antioxidant status, and activities of steroidogenic enzymes to their normal levels in testicular tissues. Moreover, histopathological finding showed that silymarin recovered the abnormalities occurred in tubules caused by B[a] P in testis of rats. On the other hand, TQ showed pro-oxidant effects and did not ameliorate the toxic effects of B[a] P on the testicular tissue since it decreased antioxidant enzymes activities and inhibited the protein expression of CYP11A1 and CYP21A2 compared to control rats. Moreover, TQ decreased the levels of testosterone, estrogen, and progesterone either in the presence or absence of B[a]P. It is concluded that B[a]P decreased testosterone levels, inhibited antioxidant enzymes activities, caused downregulation of CYP isozymes involved in steroidogenesis, and increased free radical levels in testis. Moreover, silymarin was more effective than TQ in restoring organism health and alleviating the deleterious effects caused by B[a]P in the testis of rats. Due to its negative impact, it is highly recommended to limit the use of TQ as a dietary supplement since millions of people in the Middle East are using it to improve their health.

     

Optimizing angles of rooftop photovoltaics,ratios of solar to vegetated roof systems,and economic benefits,in Portland,Oregon, USA

This study analyzed insolation data to account for multiple scattering in calculating optimal tilt angles for stationary and seasonally moving photovoltaics on three different roof types in the US Pacific Northwest: vegetated roofs, white roofs, and dark roofs. Using these results, we modeled the energy savings for vegetated roofs and roofs covered in varying numbers of photovoltaic panels. We then calculated the net present value, internal rate of return, and other economic measures for all possible combinations of covering rooftops in mixes of photovoltaic arrays and vegetation, accounting for installation costs, proposed carbon taxes, stormwater management discounts, and other relevant factors. Our results quantify how, in the US Pacific Northwest and similar locations, photovoltaics produce higher returns on investment than do vegetated roofs for new buildings, while vegetated roofs produce better returns on investment than do photovoltaics for older buildings. This is important because in many areas, some buildings have photovoltaics when a vegetated roof would have been more cost and energy efficient, while other buildings have vegetated roofs when photovoltaics would have been more cost and energy efficient. Potential applications include modifying incentive programs and other policies to account properly for building age, use, and other relevant factors to ensure building owners make the most energy-efficient decisions between photovoltaic versus vegetated roof installation. Our research also demonstrates how positive returns on investment can be realized in the US Pacific Northwest and similar regions through vegetated roofs and photovoltaics provided they are each installed optimally.     

Experimental investigations on regeneration energy and energy management strategy in series hydraulic/electric synergy system

This research work draws an insight into the experimental investigations on a series hydraulic/electric synergy system—a green transportation system. An experimental test rig of the system with all necessary sensors and instrumentation has been developed to study the energy saving through hydraulic regenerative braking. The effect of various system parameters, such as braking time, maximum accumulator pressure, pre-charge pressure of hydro-pneumatic accumulator, volumetric displacement of the hydraulic master pump, and hydraulic regeneration pump on the quantum of regeneration energy, was analyzed. In addition, an AMESim model of the real-time experimental test rig has been developed and validated with experimental results. A set of five different experimental designs (parameter variations) of the system is defined with the available standard component sizes. The best design is selected of the available experimental designs based on the maximum hydraulic regeneration energy and regeneration efficiency. It was observed that the selected design has an energy efficiency of 13.3% and a regeneration efficiency of 43.8%. An accumulator-centric control strategy for energy management is developed and implemented on the experimental test rig configured with the selected design. The effectiveness of the control strategy is tested through experiments and simulation on the developed test rig.     

Cues from a common predator cause survival-linked behavioral adjustments in Mojave Desert tortoises (Gopherus agassizii)

Behavioral Ecology and Sociobiology - Adult animals of many species often behave in a cannibalistic manner when encountering conspecific offspring. Kin discrimination is critical for avoiding the...     

Eco-design practices towards sustainable supply chain management: interpretive structural modelling (ISM) approach

Due to increasing emphasis on sustainable practices, many organisations have attempted to leverage their supply chain performance towards balancing triple bottom line dimensions (economic, environmental and social perspectives). This paper, therefore, determines the priorities of sustainable supply chain management focusing on eco-design. Interpretive structural modelling (ISM) and Matriced’ Impacts Croise’s Multiplication Appliquée a UN Classement (MIMAC) are used to identify the hierarchical structure of the relationships among eco-design dimensions, and to analyse characteristics power of each dimension on supporting eco-design practices. The relationships and characteristics power of each dimension are used to determine indicators that are effective in enhancement of eco-design practice, evaluated through sustainable supply chain performance. Results indicate that product deployment is an important approach for improving eco-design practice towards sustainable supply chain management. This emphasises the purpose and impact of eco-design on sequential supply chain activities at deployment phase. Further research is required to make an overall assessment of eco-design practices across range of manufacturing industries, given the current research is based on inputs from a limited number of experts of selected organisations.     

Recycling of high purity selenium from CIGS solar cell waste materials

Copper indium gallium diselenide (CIGS) is a promising material in thin film solar cell production. To make CIGS solar cells more competitive, both economically and environmentally, in comparison to other energy sources, methods for recycling are needed. In addition to the generally high price of the material, significant amounts of the metals are lost in the manufacturing process. The feasibility of recycling selenium from CIGS through oxidation at elevated temperatures was therefore examined. During oxidation gaseous selenium dioxide was formed and could be separated from the other elements, which remained in solid state. Upon cooling, the selenium dioxide sublimes and can be collected as crystals. After oxidation for 1 h at 800 °C all of the selenium was separated from the CIGS material. Two different reduction methods for reduction of the selenium dioxide to selenium were tested. In the first reduction method an organic molecule was used as the reducing agent in a Riley reaction. In the second reduction method sulphur dioxide gas was used. Both methods resulted in high purity selenium. This proves that the studied selenium separation method could be the first step in a recycling process aimed at the complete separation and recovery of high purity elements from CIGS.