Do differences between metal body residues reflect the differences between effects for Chironomus riparius exposed to different sediments?

Sediment characteristics are well known to interfere with toxicity, mainly through differences in terms of bioaccumulation. Here, with chironomids exposed to zinc in an artificial and a field sediment, we investigated the differences of zinc accumulation and of effects on the life cycle, at individual and population level. We used biology and energy-based modeling to analyze the data at all the levels of biological organization. This permits a reliable estimation of thresholds values for tissue residues. Differences in zinc tissue residues accounted for most of the differences between the results for both sediments (a factor of 11 for differences from 20 to 100 depending on the parameter which is considered). Taking into account accumulation and background variability, the differences relative to thresholds could be accounted for. However, it appeared that, once the threshold was passed, effects were much more pronounced for organisms exposed to artificial sediment compared to field sediment. We concluded that some sediment characteristics can enhance toxicity, in addition to their influence on the compound accumulation, even if the latter was the major source of differences in our study.     

Land cover mapping of wetland areas in an agricultural landscape using SAR and Landsat imagery

Saline wetlands in the Monegros Desert, NE Spain, are situated in an agricultural landscape which is undergoing significant changes. Agricultural intensification in recent decades and current installation of new irrigation systems threaten these valuable habitats, set to be included in the Natura2000 network. Their preservation and successful management depend on the information available regarding the transformation of surrounding areas. When soil and vegetation maps at adequate scale are not available, remote sensing is an alternative means to obtain needed data. We have used SAR data, taking advantage of the soil surface characteristics perceived in SAR images. The objective of this work is to explore the capability of multitemporal SAR data to characterize the land covers of these wetlands and their environment. We have developed specific contextual classifications which take into account the statistical properties of the radar distribution. Moreover, we tested the contribution of radar in Landsat classification.     

Promoting equity in water access: the limits of fairness of a rural water programme in semi‐arid Mozambique

Bridging the water infrastructure gap has become a major policy concern. In rural areas of Africa, access to water is as much constrained by territorial coverage as it is by the poor conditions of water points due to the difficulty in mobilizing communities for repairs. This paper examines the equity considerations of a rural water and sanitation programme in a district of Mozambique, and their impacts on the achievement of the programme's objectives. Our analysis underlines the contradictions in the conceptualization of equity in the design, planning and implementation of the programme. Even an explicitly pro‐poor strategy can fall short of delivering equity. Our findings stress the fact that overlooking local perception of equity can have a direct impact on the ability of a community to ensure the maintenance of their water points. They call for a careful definition of equity in the design of water programmes, as well as closer attention to this criterion as a precondition to achieving the long‐term objective of the programme.     

Gaming across scale in peri-urban water management: contribution from two experiences in Bolivia and Brazil

Natural resource governance is by nature multi-level, mobilizing various multi-stakeholder arenas in which a social learning approach may play a role. An approach using simulation tools such as role-playing games was tested in metropolitan areas of two South American cities: (1) in the periphery of Cochabamba, to facilitate conflict resolution stemming from the impact of urbanization on the irrigation infrastructure, and (2) in peri-urban areas of São Paulo, to assist in negotiations on land and water management in a protected catchment. Both interventions were designed to broaden the stakeholders' perspectives and facilitate the exchange of the views of different actors on water and land management using role-playing games. This paper discusses how the scale strategy embedded in the tools and in the mode of participation in fact constrained the possibility of bridging the gap between organisational levels in both situations. This calls for both the crafting of multi-level approaches able to take different levels into account, and finding adequate bridging mechanisms to enhance the integration of learning within organisations and communities.     

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.     

Fragrant legs in Paysandisia archon males (Lepidoptera, Castniidae)

Paysandisia archon was accidentally introduced into Europe where it damages endemic and ornamental palms, also threatening the date palm from North Africa. Little was known about sex pheromones in the Castniidae day-flying moth before a recent paper that concluded on the absence of female sex pheromone in P. archon. A putative identification of a short-range male pheromone, present on fore- and hindwings, was reported. In this paper, we describe the original structure of the male androconia located on the tarsi of the mid-legs. The extracts of mid-legs were analysed by GC/MS and the chemical structure of the male androconia component was identified as E2,Z13-18:OH. After extraction in solvent, biological activity of the extracts was assessed by EAG. The chemistry and the morphology of the androconia reinforce the current classification of the Castniidae in the Cossoid/Sesioid assemblage and provide new information on the chemical ecology in day-flying Lepidoptera and suit the recent paper describing the courtship behaviour