Temporal dynamics of Chaoborus larvae (Diptera : Chaoboridae) in the tropical ecosystem (lake Ayamé I ; Côte d’Ivoire).

Chaoborus larvae are voracious predators of zooplankton able to change their specific composition and size structure. Thus they appear as competitors of fish. They also represent food for planktophage fish. The temporal dynamics of Chaoborus larvae was studied (from january to october 1997) in the fishery of Bakro (5°33’N and 3°15’W) situated in lake Ayamé I (Côte d’Ivoire). Two peaks of density were observed : the most pronouced in March (end of the major dry season) with 747 ind./m2, and another, less pronouced in June (end of the major rainy season), with 280 ind./m2. Differences between densities may well be explained by the advent of the rainy season which leads to a decline in trophic resources (zooplankton) and exposes Chaoborus larvae to predation by fish.Key-words : Chaoborus larvae, Dynamics, lake Ayamé I, Côte d’Ivoire,West Africa

A global agenda for advancing freshwater biodiversity research

This manuscript is a contribution of the Alliance for Freshwater Life (www.allianceforfreshwaterlife.org). We thank Nick Bond, Lisa Bossenbroek, Lekima Copeland, Dean Jacobsen, Maria Cecilia Londo?o, David Lopez, Jaime Ricardo Garcia Marquez, Ketlhatlogile Mosepele, Nunia Thomas-Moko, Qiwei Wei and the authors of Living Waters: A Research Agenda for the Biodiversity of Inland and Coastal Waters for their contributions. We also thank Peter Thrall, Ian Harrison and two anonymous referees for their valuable comments that helped improve the manuscript. Open access funding enabled and organised by Projekt DEAL

Exploring perceptions of advertising ethics: an informant-derived approach

Whilst considerable research exists on determining consumer responses to pre-determined statements within numerous ad ethics contexts, our understanding of consumer thoughts regarding ad ethics in general remains lacking. The purpose of our study therefore is to provide a first illustration of an emic and informant-based derivation of perceived ad ethics. The authors use multi-dimensional scaling as an approach enabling the emic, or locally derived deconstruction of perceived ad ethics. Given recent calls to develop our understanding of ad ethics in different cultural contexts, and in particular within the Middle East and North Africa (MENA) region, we use Lebanon—the most ethically charged advertising environment within MENA—as an illustrative context for our study. Results confirm the multi-faceted and pluralistic nature of ad ethics as comprising a number of dimensional themes already salient in the existing literature but in addition, we also find evidence for a bipolar relationship between individual themes. The specific pattern of inductively derived relationships is culturally bound. Implications of the findings are discussed, followed by limitations of the study and recommendations for further research

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.Peer reviewe

Epilithic chironomid larvae and water enrichment: is larval distribution explained by epilithon quantity or quality?

International audienceThe effects of nutrient enrichment of stream water on epilithic chironomid larval assemblages were examined during spring in a Mediterranean catchment. Three reaches that differed in degree of enrichment were selected for comparison. Water chemistry, epilithon biomass (as ash-free dry mass [AFDM]), epilithic algal biomass (as chlorophyll a [chl a]), algal biovolumes, and algal composition were analyzed to determine their association with density and taxonomic composition of epilithic chironomids. Kendall's s coefficient of rank correlations and canonical correlation analysis were used to evaluate correlations between the chironomid and algal assemblages. Significant correlations were found between chironomid larval densities and total algal cell densities and biovolumes. Chironomid larval densities were not significantly correlated with chl a or AFDM. Several contrasting trends were identified in the relationships between chironomid and algal assemblages. Densities of fixed-tube scrapers, such as Eukiefferiella claripennis and Cricotopus bicinctus, were strongly correlated with biovolumes of Rhodophyceae and Diatomophyceae, whereas densities of free-living scrapers, such as Thienemaniella, were slightly correlated with Chlorophyceae biovolume. Therefore, nutrient enrichment strongly influenced epilithic chironomid assemblage structure through its effects on biovolumes and cell densities of the epilithic algal assemblages

Chironomid (Insecta : Diptera) assemblages from a gradient of lotic and lentic waterbodies in river floodplains of France: A methodological tool for paleoecological applications.

International audienc

Les affluents des cours d'eau méditerranéens: rôle dans le maintien de la diversité du macrobenthos

International audienceThe taxonomic richness erosion and the role of tributaries in the maintenance of the taxonomic richness were considered in a Mediterranean catchment in southeastern France. Nine stations were chosen along the Arc stream (three stations downstream from an organic effluent and one station upstream from the pollution source) and on two groups of tributaries (three intermittent and two perennial). High biodiversity erosion was noticed in the main stem, revealing diffuse sources of pollution added to the expected effect of the localized organic pollution. Jackknife richness estimator and beta diversity indicated that the intermittent tributaries had the highest richness values and harboured 70% of the taxa recorded at the catchment scale. The intermittent flow tributaries seem to play a major role in maintaining the taxonomic richness in such catchments, highly impacted by anthropogenic activities. The detailed examination and the preservation of these ecosystems should be an important step in catchment management, and support the need for catchment-scale conservation of freshwater invertebrates.L'érosion de la richesse taxinomique ainsi que le rôle des affluents temporaires dans le maintien de cette richesse taxinomique on été étudiés dans un petit bassin versant méditerranéen du Sud-Est de la France. Neuf stations d'études on été choisies le long de la rivière Arc (une station en amont de la station d'épuration de Trets et trois en aval), ainsi que sur deux types d'affluents (trois affluents temporaires et deux permanents). Une importante érosion de la richesse taxinomique a été observée le long de la rivière Arc, même dans la station située en amont de la source de pollution organique localisée ; ceci suggère l'existence de pollutions diffuses dans le bassin versant. L'estimation de la richesse par la méthode Jackknife ainsi que la diversité bêta montrent que les affluents temporaires abritent 70% des macroinvertébrés benthiques recensés dans cette partie du bassin versant. Ces affluents semblent jouer un rôle important dans le maintien de la richesse taxinomique dans ce type de bassin et plaide pour la conservation de la faune benthique d'invertébrés à l'échelle du bassin versan