Commercial experience with miscanthus crops: Establishment,yields and environmental observations

This study investigates the condition of commercial miscanthus fields, growers’ concerns and reasons for growing the crop and also the modelling of a realistic commercial yield. Juvenile and mature Miscanthus × giganteus crops of varying age are surveyed in growers’ fields across mid‐England. We record in‐field plant density counts and the morphology of crops of different ages. Mature crops thrive on both clay and sandy soils. Plants surveyed appear robust to drought, weeds and disease, the only vulnerability is rhizome condition when planting. Mature miscanthus planted pre‐2014 continues to develop, spreading into planting gaps and growing more tillers. In stands planted post‐2014, improved planting techniques reduce planting gaps and create a reasonably consistent planting density of 12,500 plants/ha. The main reason for growers' investment in miscanthus is not financial return, but relates to its low requirement for field operations, low maintenance cost and regeneration. This offers practical solutions for difficult field access and social acceptability near public places (related to spray operations and crop vandalism). Wildlife is abundant in these fields, largely undisturbed except for harvest. This contributes to the greening of agriculture; fields are also used for gamebird cover and educational tours. This crop is solving practical problems for growers while improving the environment. Observed yield data indicate gradual yield increase with crop age, a yield plateau but no yield decrease since 2006. In stands with low planting densities, yields plateau after 9 years. Surveyed yield data are used to parameterize the MiscanFor bioenergy model. This produces options to simulate either juvenile yields or a yield for a landscape containing different aged crops. For mature English crop yields of 12 t ha^?1 year^?1, second‐ and third‐year juvenile harvests average 7 t ha^?1 year^?1 and a surrounding 10 km by 10 km area of distributed crop age would average 9 t ha^?1 year^?1.     

Food vs. fuel: the use of land for lignocellulosic ‘next generation’ energy crops that minimize competition with primary food production

This review addresses the main issues concerning anticipated demands for the use of land for food and for bioenergy. It should be possible to meet increasing demands for food using existing and new technologies although this may not be easily or cheaply accomplished. The alleviation of hunger depends on food accessibility as well as food availability. Modern civilizations also require energy. This article presents the vision for bioenergy in terms of four major gains for society: a reduction in C emissions from the substitution of fossil fuels with appropriate energy crops; a significant contribution to energy security by reductions in fossil fuel dependence, for example, to meet government targets; new options that stimulate rural and urban economic development, and reduced dependence of global agriculture on fossil fuels. This vision is likely to be best fulfilled by the use of dedicated perennial bioenergy crops. We outline a number of factors that need to be taken into account in estimating the land area available for bioenergy. In terms of provisioning services, the value of biofuels is estimated at $54.7?$330 bn per year at a crude oil price of $100 per barrel. In terms of regulatory services, the value of carbon emissions saved is estimated at $56?$218 bn at a carbon price of $40 per tonne. Although global government subsidies for biofuels have been estimated at $20 bn (IEA, 2010b), these are dwarfed by subsidies for fossil fuel consumption ($312 bn; IEA, 2010b) and by total agricultural support for food and commodity crops ($383.7 bn in 2009; OECD, 2010).     

Tensile deformation of bacterial cellulose composites

The polymeric basis for the mechanical properties of primary plant cell walls has been investigated by forming analogous composites based on fermentation of the bacterium Acetobacter xylinus, either alone or in the presence of xyloglucan or pectin. Simultaneous small-angle X-ray scattering and uniaxial deformation experiments has shown how the cellulose microfibrils reorient during deformation. Despite very different stress/strain curves, the reorientation behaviour is similar, regardless of the presence or absence of xyloglucan or pectin. A simple theory has been developed to predict the orientation behaviour. This is qualitatively similar to the measured behaviour, but differs quantitatively.     

Measurement of cellular repair activities for oxidative DNA damage

Two related assays capable of determining cell extract repair activities for different oxidative lesions in DNA are described. Both assays measure the incorporation of radiolabeled nucleotides during repair of an oxidatively damaged template in a cell-free system. The assays differ in the type of oxidative damage present in the DNA. In one, singlet oxygen is used to generate predominantly 8-oxo-2'-deoxyguanosine lesions. In the other, hydroxyl radicals are used to generate a broad spectrum of damage including oxidized bases and strand breaks. Assay conditions were adjusted to ensure that radiolabel incorporation was directly proportional to cell extract repair activity. These assays represent sensitive tools for investigating the regulation of repair systems for oxidative DNA damage.     

Balancing in- and out-breeding by the predatory mite <Emphasis Type="Italic">Phytoseiulus persimilis</Emphasis>

In- and out-breeding depressions are commonly observed phenomena in sexually reproducing organisms with a patchy distribution pattern, and spatial segmentation and/or isolation of groups. At the genetic level, inbreeding depression is due to increased homozygosity, whereas outbreeding depression is due to inferior genetic compatibility of mates. Optimal outbreeding theory suggests that intermediate levels of mate relatedness should provide for the highest fitness gains. Here, we assessed the fitness consequences of genetic relatedness between mates in plant-inhabiting predatory mites Phytoseiulus persimilis, which are obligatory sexually reproducing but haplo-diploid. Both females and males arise from fertilized eggs but males lose the paternal chromosome set during embryogenesis, dubbed pseudo-arrhenotoky. Phytoseiulus persimilis are highly efficacious in reducing crop-damaging spider mite populations and widely used in biological control. Using iso-female lines of two populations, from Sicily and Greece, we assessed the fecundity of females, and sex ratio of their offspring, that mated with either a sibling, a male from the same population or a male from the other population. Additionally, we recorded mating latency and duration. Females mating with a male from the same population produced more eggs, with a lower female bias, over a longer time than females mating with a sibling or with a male from the other population. Mating latency was unaffected by mate relatedness; mating duration was disproportionally long in sibling couples, likely indicating female reluctance to mate and sub-optimal spermatophore transfer. Our study provides a rare example of in- and out-breeding depression in a haplo-diploid arthropod, supporting the optimal outbreeding theory.     

Synergies and trade‐offs between renewable energy expansion and biodiversity conservation – a cross‐national multifactor analysis

Increased deployment of renewable energy can contribute towards mitigating climate change and improving air quality, wealth and development. However, renewable energy technologies are not free of environmental impacts; thus, it is important to identify opportunities and potential threats from the expansion of renewable energy deployment. Currently, there is no cross‐national comprehensive analysis linking renewable energy potential simultaneously to socio‐economic and political factors and biodiversity priority locations. Here, we quantify the relationship between the fraction of land‐based renewable energy (including solar photovoltaic, wind and bioenergy) potential available outside the top biodiversity areas (i.e. outside the highest ranked 30% priority areas for biodiversity conservation) within each country, with selected socio‐economic and geopolitical factors as well as biodiversity assets. We do so for two scenarios that identify priority areas for biodiversity conservation alternatively in a globally coordinated manner vs. separately for individual countries. We show that very different opportunities and challenges emerge if the priority areas for biodiversity protection are identified globally or designated nationally. In the former scenario, potential for solar, wind and bioenergy outside the top biodiversity areas is highest in developing countries, in sparsely populated countries and in countries of low biodiversity potential but with high air pollution mortality. Conversely, when priority areas for biodiversity protection are designated nationally, renewable energy potential outside the top biodiversity areas is highest in countries with good governance but also in countries with high biodiversity potential and population density. Overall, these results identify both clear opportunities but also risks that should be considered carefully when making decisions about renewable energy policies.