Male mating competitiveness and age-dependent relationship between testosterone and social rank in bighorn sheep

In males, the acquisition and development of behavioral and morphological secondary sexual traits typically depends on testosterone and correlates with mating success. Testosterone level could affect competition for mates and thus be a target of sexual selection. We sought to relate testosterone levels to male mating competitiveness, by teasing apart the relationships between testosterone, behavior, and growth before the mating period. We monitored 24 adult bighorn rams (Ovis canadensis) at Ram Mountain, Alberta, from 2008 to 2011. Using linear mixed models, we tested the relationships between testosterone metabolites in feces, social rank, and both growth and size of two sexually selected traits: horns and body mass. The correlation between testosterone and social rank varied with age. Testosterone and rank were weakly and negatively correlated for young rams, positively correlated for prime-aged rams, and negatively correlated for older rams. Although testosterone had an increasingly positive effect on total horn length until 8 years of age, we could not detect any effects on annual growth rate of horns or body mass. Testosterone may be related to male’s ability to compete for mates through its relationship with behaviors determining social rank, rather than by influencing the development of morphological traits. Differences in testosterone levels among competitors may be a proximate cause of variance in fitness.     

Responding to climate variability: the opening of an artificial mouth on the Senegal River

The city of Saint-Louis is marked by recurrent floods, despite the decrease in rainfall. The town that grew downstream the vast plain where Senegalese-Mauritanian basin topography flattens considerably has experienced periodic flooding since its foundation. In 2003, the premature flooding of the Senegal River urged the Senegalese authorities to take the initiative to open a breach in the coastal sand strip of the “Langue de Barbarie,” in order to evacuate the water surplus from the river to the ocean and therefore resolve forever the problem of river flooding. But the disruption of estuarine dynamics has led to a rapid expansion of this gap: a few meters wide at its excavation, it reaches over 2,700 m in August 2009. Moreover, 10 months after the widening of the gap, the old river mouth was completely closed. If the natural movement of a mouth can be observed on some major deltas in the world (even on the Senegal River in the past), this is here a true man-made relocation. Based on the statistical analysis of series of hydrological data, this article demonstrates on the one hand that climatic conditions in 2003 which generated a major flood is an anomaly detected in the sequence of dry climate variability observed in the Sahel. On the other hand, it studies the rapid evolution of this new mouth of the Senegal River and discusses some of impacts on the regional social–ecological system, in this sensitive Sahelian environment.     

Development of rearing and testing protocols for a new freshwater sediment test species: the gastropod Valvata piscinalis

This paper aimed at proposing rearing and testing protocols for Valvata piscinalis, a new potential species for sediment toxicity testing. Such tests were developed since this species reliably represents the bio/ecological characteristics of other gastropods. It may thus be representative of their sensitivity to chemicals. V. piscinalis was successfully cultured in our laboratory for six generations. Cultures provided a high productivity for a low working time and low costs. The tests conditions we proposed seemed to be relevant for the development of reliable tests with this species. Indeed, hatching probability of egg-capsules, as well as embryo, newborn and juvenile survival rates, were close to 100%. Moreover, growth rates and fecundity were significantly higher than in field and in other laboratory studies. Partial life-cycle tests on clean sediments were achieved for various feeding levels to determine survival, growth and reproduction patterns, ad libitum feeding level and life cycle parameters values. Ad libitum feeding levels for newborn, juveniles and adults were 0.1, 0.4 and 0.8 mg Tetramin/individual/working day. Growth tests with zinc-spiked sediments provided a no-effect concentration and a lowest effect concentration of respectively 200 and 624 mg zinc/kg dry sediment. Other growth tests on spiked sediments we ran at our laboratory with second, third and fourth instars larvae of Chironomus riparius pointed out that V. piscinalis was more sensible to zinc than the chironomid, which is a routine test species in ecotoxicology. According to these results, V. piscinalis is a promising candidate species for sediment toxicity testing.     

Influence of organic matter on municipal solid waste incinerator bottom ash carbonation

The biodegradation of organic matter in municipal solid waste incinerator (MSWI) bottom ash was studied in order to investigate the interaction between the CO(2) produced by microbial respiration and bottom ash. Respiration tests were performed on bottom ash at different moisture contents in an incubator at 30 degrees C. O(2) consumption and CO(2) production were monitored and quantified. Leaching tests were carried out at the end of the experiments. Total organic carbon (TOC) leaching had decreased. Over a period of three weeks, pH decreased from 10.7 to 8.2 and bottom ash was considered to be fully carbonated. This showed that the organic matter found in bottom ash can provide a substrate for microbial activity. The CO(2) produced by microbial respiration was directly dissolved in bottom ash pore water in order to be mineralized in carbonate form. The origin of the carbon dioxide which induces maturation of bottom ash on weathering areas has never been really discussed and is often presumed to be atmospheric CO(2). However, biodegradation of organic matter could contribute for a large part to this phenomenon, depending on field-scale physico-chemical weathering conditions.     

Alteration of steroid hormone profile in juvenile turbot (Psetta maxima) as a consequence of short-term exposure to 17alpha-ethynylestradiol

The synthetic estrogen 17alpha-ethynylestradiol (EE2) is among the most potent xenoestrogens found in treated sewage. Adverse effects have been reported in fish exposed to this chemical, such as vitellogenin induction or alteration of gonad structure. In this study, the effects of EE2 on sex steroid profile in juvenile turbot (Psetta maxima) were investigated in a 15-day in vivo experiment. An analytical method was developed for the simultaneous gas chromatography/mass spectrometry determination of 14 steroids in gonads, plasma and bile. The impact of EE2 on the endocrine status of juvenile turbot was sex-dependent, since males were much more sensitive than females. Even at very low concentration (3.5 ng l(-1)), EE2 depressed androgen production as well as plasma levels in males. Androstenedione and 11-ketotestosterone were highly affected by EE2-exposure, since their production was suppressed in EE2-treated males. Furthermore, testis estrogen production and conjugation increased as a consequence of EE2 exposure. Overall, the ratio of androgens to estrogens in EE2-exposed males dropped in testis and plasma and reached values observed in females. These results indicate that juvenile male turbots are susceptible to hormonal imbalance as a consequence of short-term exposure to environmentally relevant EE2 levels.     

Towards a multidisciplinary and integrated strategy in the assessment of adverse health effects related to air pollution: the case study of Cracow (Poland) and asthma

Complex interaction between anthropogenic activities, air quality and human health in urban areas, such as in Cracow sustains the need for the development of an interdisciplinary and integrated risk-assessment methodology. In such purpose, we propose a pilot study performed on asthmatics and based on a combined use of a biomarker, such as metallothionein 2A (MT-2A) in the characterization of human exposure to one or a mixture of pollutants and of Geographical Information Systems (G.I.S.) which integrates climatic and urban anthropogenic parameters in the assessment of spatio-temporal dispersion of air pollutants. Considering global incidence of air pollution on asthma and on peripheral blood lymphocytes MT-2A expression should provide a complementary information on biological risks linked to urban anthropogenic activities. Such study would help for the establishment of a sustainable development in urban areas that can maintain the integrity of air quality and preserve human health.     

Dispersal depression with habitat fragmentation in the bog fritillary butterfly

Habitat fragmentation is expected to impose strong selective pressures on dispersal rates. However, evolutionary responses of dispersal are not self-evident, since various selection pressures act in opposite directions. Here we disentangled the components of dispersal behavior in a metapopulation context using the Virtual Migration model, and we linked their variation to habitat fragmentation in the specialist butterfly Proclossiana eunomia. Our study provided a nearly unique opportunity to study how habitat fragmentation modifies dispersal at the landscape scale, as opposed to microlandscapes or simulation studies. Indeed, we studied the same species in four landscapes with various habitat fragmentation levels, in which large amounts of field data were collected and analyzed using similar methodologies. We showed the existence of quantitative variations in dispersal behavior correlated with increased fragmentation. Dispersal propensity from habitat patches (for a given patch size), and mortality during dispersal (for a given patch connectivity) were lower in more fragmented landscapes. We suggest that these were the consequences of two different evolutionary responses of dispersal behavior at the individual level: (1) when fragmentation increased, the reluctance of individuals to cross habitat patch boundaries also increased; (2) when individuals dispersed, they flew straighter in the matrix, which is the best strategy to improve dispersal success. Such evolutionary responses could generate complex nonlinear patterns of dispersal changes at the metapopulation level according to habitat fragmentation. Due to the small size and increased isolation of habitat patches in fragmented landscapes, overall emigration rate and mortality during dispersal remained high. As a consequence, successful dispersal at the metapopulation scale remained limited. Therefore, to what extent the selection of individuals with a lower dispersal propensity and a higher survival during dispersal is able to limit detrimental effects of habitat fragmentation on dispersal success is unknown, and any conclusion that metapopulations would compensate for them is flawed.     

Evaluation of indoor radon measurements in Hungary

The RAD Laboratory measured annual means of radon activity concentrations in 15 277 first-floor rooms of dwellings and in 325 rooms on upper floors in Hungary (1994-2004). The original purpose of the survey was to find radon-prone area in Hungary. The maximum measured value was 5800 Bq m(-3), while the minimum was 10 Bq m(-3). Due to geological diversity and different structures of buildings, the data set of first-floor rooms did not follow the lognormal distribution. Therefore, strata were chosen so that the measured data fitted the lognormal distribution. The numbers of dwellings above a given radon level were determined in each stratum. The national distribution was then taken as the sum of the individual distributions of all strata. This distribution was not lognormal. The parameters of the best fitting lognormal distribution were GM = 58 Bq m(-3), GSD = 2.2. The weighted averages of strata values GM = 62 Bq m(-3), GSD=2.1 were obtained corresponding to 92% of Hungarian dwellings.     

Taking Action Against Ocean Acidification: A Review of Management and Policy Options

Ocean acidification has emerged over the last two decades as one of the largest threats to marine organisms and ecosystems. However, most research efforts on ocean acidification have so far neglected management and related policy issues to focus instead on understanding its ecological and biogeochemical implications. This shortfall is addressed here with a systematic, international and critical review of management and policy options. In particular, we investigate the assumption that fighting acidification is mainly, but not only, about reducing CO₂ emissions, and explore the leeway that this emerging problem may open in old environmental issues. We review nine types of management responses, initially grouped under four categories: preventing ocean acidification; strengthening ecosystem resilience; adapting human activities; and repairing damages. Connecting and comparing options leads to classifying them, in a qualitative way, according to their potential and feasibility. While reducing CO₂ emissions is confirmed as the key action that must be taken against acidification, some of the other options appear to have the potential to buy time, e.g. by relieving the pressure of other stressors, and help marine life face unavoidable acidification. Although the existing legal basis to take action shows few gaps, policy challenges are significant: tackling them will mean succeeding in various areas of environmental management where we failed to a large extent so far.     

OPERA: a New High-Resolution Energy System Model for Sector Integration Research

Environmental Modeling & Assessment - This article introduces and describes OPERA, a new technology-rich bottom-up energy system optimization model for the Netherlands. We give a detailed...