Gravel pits support waterbird diversity in an urban landscape

We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five were regionally rare. We used the Self Organizing Map algorithm to calculate the probabilities of presence of species, and to bring out habitat conditions that predict assemblage patterns. The age of the pits did not correlate with assemblage composition and species richness. There was a positive influence of macrophyte cover on waterbird species richness. Larger pits did not support more species, but species richness increased with connectivity. As alternative wetland habitats, gravel pits are attractive to waterbirds, when they act as stepping stones that ensure connectivity between larger natural and/or artificial wetlands separated in space

Groundwater of Rome

This paper describes the contents of the new Hydrogeological Map of the City of Rome (1:50,000 scale). The map extends to the entire municipality (1285 km2) and is based on both the most recent scientific studies on the groundwater field and new survey activities carried out in order to fill the data gaps in several areas of the examined territory. The map is the result of a combination of different urban groundwater expertise and Geographic Information System (GIS)-based mapping performed using the most recent available data and has been produced with the intention of furnishing the City of Rome with the most recent and updated information regarding groundwater

Diel dynamics of young and small fishes in a side-channel of the River Garonne, France, before and after a late-summer spate

We examined diel patterns in fish distribution, size and relative density in a side-channel of the River Garonne before and after a late-summer spate as part of a study of the role of floodplain wetlands in fish recruitment. Increases in fish size (SL) at night were mostly unaffected by the spate, whereas an increase in fish density at night, not observed prior to the spate, was observed in some species post spate. Microhabitat use was variable at dusk and night before and after the spate, but dawn and daytime microhabitat use were less variable after the spate. Water velocity, macrophytes and ligneous debris were the most important microhabitat variables prior to the spate, but were replaced thereafter by substratum composition and bank slope. Changes in microhabitat electivities were most apparent in abundant species, with shifts in depth, substratum and water velocity preferences in 0+ gudgeon Gobio gobio and 0+ chub Leuciscus cephalus. Our results indicate that habitat suitability (or preference) curves and electivity profiles are influenced by variations in river discharge, emphasizing the importance of using multiple samplings (diel, within-season, between-season) when setting habitat criteria for river management and when assessing the role of floodplain wetlands in fish recruitment

Utilisation des microhabitats par le vairon, le goujon et la loche franche dans trois rivières du sud-ouest de la France

L'utilisation des microhabitats par le vairon, Phoxinus phoxinus (L.), le goujon, Gobio gobio (L.) et la loche franche, Barbatula barbatula (L.) a été étudiée en conditions d'étiage d'hiver et d'été dans trois rivières du sud-ouest de la France : l'Ariège, la Nive et le Gave de Pau. Les poissons ont été échantillonnés par pêche électrique selon la méthode de l'Echantillonnage Ponctuel d'Abondance. Onze variables du milieu ont été prises en compte pour décrire l'environnement ponctuel des poissons. Pour chaque rivière, les associations interspécifiques et espèces-variables du milieu ont été calculées et comparées en fonction de la saison. Des variations saisonnières de l'utilisation du microhabitat et des associations interspécifiques ont été observées sur les trois rivières. La nature du substrat et la présence d'abris végétaux jouent un rôle important dans la microrépartition du vairon, du goujon et de la loche franche. Ces structures offrent aux poissons des habitats de refuge et de nutrition privilégiés

Spatial distribution patterns and causes of decline of three freshwater species with different biological traits (white-clawed crayfish, bullhead, freshwater pearl mussel) : a review

International audienc

Seasonal changes of periphytic nutritive quality for Sicyopterus lagocephalus (Pallas, 1770) (gobiidae) in three streams of Reunion Island

The biomass and the biochemical composition of periphyton were studied during one year in three streams of Réunion Island. The results revealed that nutritional conditions for fish development were most favourable during the dry season. The nutritive value of periphyton was highest in the Marsouins and Mât streams and remained the lowest in the Roches stream. Food availability was strongly affected by high flow, particularly during the exceptional hydrological events of February 1998 (cyclonic high flows). Study of seasonal variations of morphophysiological characteristics and biochemical composition (lipids, proteins) of the grazer gobiidae Sicyopterus lagocephalus showed that inspite of unfavourable nutritional conditions caused by hydrological disturbances, fish continue their reproduction which coincides with the summer high flow period. The significant depletion of lipid reserves which express a deterioration in animal condition is influenced by flooding period. At this time of gonad development involving an additional energy investment, fish were not able to recover a stable nutritional state after the complete achievement of the reproduction cycle. Except during this period, there is a weak participation of the reproductive physiological processes in the seasonal changes of somatic composition of this fish