Variation in levels of reactive oxygen species is explained by maternal identity, sex and body-size-corrected clutch size in a lizard

Many organisms show differences between males and females in growth rate and crucial life history parameters, such as longevity. Considering this, we may expect levels of toxic metabolic by-products of the respiratory chain, such as reactive oxygen species (ROS), to vary with age and sex. Here, we analyse ROS levels in female Australian painted dragon lizards (Ctenophorus pictus) and their offspring using fluorescent probes and flow cytometry. Basal level of four ROS species (singlet oxygen, peroxynitrite, superoxide and H₂O₂) measured with a combined marker, and superoxide measured specifically, varied significantly among families but not between the sexes. When blood cells from offspring were chemically encouraged to accelerate the electron transport chain by mitochondrial uncoupling, net superoxide levels were three times higher in daughters than sons (resulting in levels outside of the normal ROS range) and varied among mothers depending on offspring sex (significant interaction between maternal identity and offspring sex). In offspring, there were depressive effects on ROS of size-controlled relative clutch size, which relies directly on circulating levels of vitellogenin, a confirmed antioxidant in some species. Thus, levels of reactive oxygen species varies among females, offspring and in relation to reproductive investment in a manner that makes its regulatory processes likely targets of selection.     

Alternating copolymers and alternative device geometries for organic photovoltaics

The efficiency of conversion of light to electrical energy with the help of conjugated polymers and molecules is rapidly improving. The optical absorption properties of these materials can be designed, and implemented via molecular engineering. Full coverage of the solar spectrum is thus feasible. Narrow absorption spectra allow construction of tandem solar cells. The poor transport properties of these materials require thin devices, which limits optical absorption. Alternative device geometries for these flexible materials compensate for the optical absorption by light trapping, and allow tandem cells.     

The Future of Baltic Sea Populations: Local Extinction or Evolutionary Rescue?

Environmental change challenges local and global survival of populations and species. In a species-poor environment like the Baltic Sea this is particularly critical as major ecosystem functions may be upheld by single species. A complex interplay between demographic and genetic characteristics of species and populations determines risks of local extinction, chances of re-establishment of lost populations, and tolerance to environmental changes by evolution of new adaptations. Recent studies show that Baltic populations of dominant marine species are locally adapted, have lost genetic variation and are relatively isolated. In addition, some have evolved unusually high degrees of clonality and others are representatives of endemic (unique) evolutionary lineages. We here suggest that a consequence of local adaptation, isolation and genetic endemism is an increased risk of failure in restoring extinct Baltic populations. Additionally, restricted availability of genetic variation owing to lost variation and isolation may negatively impact the potential for evolutionary rescue following environmental change.     

The spatial and temporal change of cropland in the Scandinavian Peninsula during 1875–1999

Land use and land cover change (LUCC) has emerged as an important issue of global change with significant influences on the geochemical cycle and regional climate change. Understanding the historical changes of land use and analyzing the environmental effects of LUCC make such reconstructions important. Based on historical statistics, this article reconstructs cropland area at the municipality level (härad/kommun) in the Scandinavian Peninsula during 1875–1999. The total acreage of cropland increased 36.84 % during 1875–1930, kept stable during 1930–1950, and decreased 14.25 % during 1950–1999. The croplands of Sweden and Norway both increased before 1950 and changed in different ways during 1950–1999 when the cropland decreased by 19.79 % in Sweden but increased by 9.63 % in Norway. The counties in the south Scandinavian Peninsula owned most of the cropland, with a cropland proportion of over 20 %, and experienced relatively obvious cropland changes. Growth centers with a rate of increase of over 5 % during 1875–1910 were found in Skåne, Stockholm, the Uppsala counties in Sweden, and the area around Oslo county in Norway. The general cropland distribution showed almost no change during this period, which mainly reflects the suitability of the natural conditions for agriculture. Multi-social factors co-impacted land use activities and induced temporal and spatial variations of the cropland. These factors included food supply, world trade, wars, agriculture policies, the economic and political environment, urbanization, and national differences. Compared with the widely used global land use dataset Historical Database of the Global Environment (HYDE), this study shows different cropland change curves before 1950. This article is a case study showing that the hindcasting model of the HYDE dataset has difficulty estimating multi-determined cropland change in the Scandinavian Peninsula, and the empirical study contributes to the improvement of the accuracy of historical land use data at the regional level.     

Dense resistivity and induced polarization profiling for a landfill restoration project at H?rl?v, Southern Sweden.

A resistivity and time-domain induced polarization (IP) survey was conducted at a landfill site under restoration at H?rl?v in Southern Sweden. The covering of the landfill had begun some years ago, without keeping precise records of the work done, as is usual in such procedures. The survey was conducted in two steps, on two adjacent areas. First, a number of geoelectrical sections were made on a partly covered area that had been investigated earlier by auger drilling, in order to assist restoration. Then, a second area that should have received its final cover was imaged, and some defects in the cover could be detected and repaired. The resistivity and time-domain IP results were consistent with the results of the geotechnical drillings, and they enabled quasi-continuous mapping along the profiles. Three-dimensional visualization showed the overall consistency of the two-dimensional lines, and helped to generate a global view of the site. In spite of some ambiguities, cover and waste could be distinguished in most cases. In particular, fine-grained cover materials could be clearly distinguished from other cover materials.     

Depletion of coastal predatory fish sub-stocks coincided with the largest sea urchin grazing event observed in the NE Atlantic

In this contribution, we propose fishery driven predator release as the cause for the largest grazing event ever observed in the NE Atlantic. Based on the evolving appreciation of limits to population connectivity, published and previously unpublished data, we discuss whether overfishing caused a grazer bloom of the sea urchin (Strongylocentrotus droebachiensis) resulting in overgrazing of more than 2000 km² kelp (Laminaria hyperborea) forest along Norwegian and Russian coasts during the 1970 s. We show that coastal fisheries likely depleted predatory coastal fish stocks through modernization of fishing methods and fleet. These fish were important predators on urchins and the reduction coincided with the urchin bloom. From this circumstantial evidence, we hypothesize that coastal predatory fish were important in regulating sea urchins, and that a local population dynamics perspective is necessary in management of coastal ecosystems.     

Building future scenarios and uncovering persisting challenges of participatory forest management in Chilimo Forest, Central Ethiopia

We examined the changes in forest status and people's livelihoods through building future scenarios for Chilimo Forest in Central Ethiopia where participatory forest management (PFM) is being implemented. Participatory methods were employed to collect data, and a dynamic modeling technique was applied to explore trends over time. By integrating the more quantitative model outputs with qualitative insights, information on forests and livelihoods was summarized and returned to users, both to inform them and get feedback. A scenario of open access without PFM provides higher income benefits in the short term but not over the longer term, as compared to a scenario with PFM. Follow up meetings were organized with national decision makers to explore the possibility of new provisions in the national forest proclamation related to joint community-state ownership of forests. Project implementers must constantly work towards improving short term incentives from PFM, as these may be insufficient to garner support for PFM. Other necessary elements for PFM to succeed include: ensuring active participation of the communities in the process; and, clarifying and harmonizing the rules and regulations at different levels.     

Simulating sulfadimidine transport in surface runoff and soil at the microplot and field scale

To prevent residues of veterinary medicinal products (VMPs) from contaminating surface waters and ground water, an environmental impact assessment is required before a new product is allowed on the market. Physically based simulation models are advocated for the calculation of predicted environmental concentrations at higher tiers of the assessment process. However, the validation status of potentially useful models is poor for VMP transport. The objective of this study was to evaluate the dual-permeability model MACRO for simulation of transport of sulfonamide antibiotics in surface runoff and soil. Special focus was on effects of solute application in liquid manure, which may alter the hydraulic properties at the soil surface. To this end we used data from a microplot runoff experiment and a field experiment, both conducted on the same clay loam soil prone to preferential flow. Results showed that the model could accurately simulate concentrations of sulfadimidine and the nonreactive tracer bromide in runoff and in soil from the microplot experiments. The use of posterior parameter distributions from calibrations using the microplot data resulted in poor simulations for the field data of total sulfadimidine losses. The poor results may be due to surface runoff being instantly transferred off the field in the model, whereas in reality re-infiltration may occur. The effects of the manure application were reflected in smaller total and micropore hydraulic conductivities compared with the application in aqueous solution. These effects could easily be accounted for in regulatory modeling.     

Male contests in the scarlet rosefinch (Carpodacus erythrinus) in relation to asymmetries in resource holding power and pairing status

Summary Inter-male contests in relation to asymmetries in their pairing status and resource holding power were studied in a population of the Scarlet rosefinch. Since males in this species do not defend territories before nest building, and since most males have full adult plumage, possession of territory and age are unlikely to be used as cues in the settlement of contests. Rather, two other features are used, namely size and pairing status. In this study, contests between two unpaired males were usually short displacements, whereas 56% of contests between two paired males were escalated. In the first case, the smaller male withdrew in all contests, whereas in the second case there was an equal probability of withdrawal with regard to size. There was no relationship between size difference and the probability of escalation in the contests. Most of the fights between paired and unpaired males escalated, namely in 60% of the cases where the unpaired male was smaller and in 75% of the cases where he was larger. The unpaired male withdrew in 18 out of 23 contests, suggesting that pairing status is more important than size in determining the outcome of a contest. There was no variance in size differences between contestants in short and escalated contests. This study demonstrates that there is a high competition between males for females in this population.