1,721,168 research outputs found
Jean XXII et les Joachimites du Midi
No full textBartoli Marco. Jean XXII et les Joachimites du Midi. In: La papauté d'Avignon et le Languedoc. Toulouse : Éditions Privat, 1991. pp. 237-256. (Cahiers de Fanjeaux, 26
Zone umide perifluviali: processi biogeochimici, funzioni ecologiche, problemi di gestione e conservazione
No full textLimnological characteristics and recent ostracods (Crustacea, Ostracoda) of freshwater wetlands in the Parco Oglio Sud (Northern Italy)
No full textWe report the results of a study carried out in 2002 on the main limnological characteristics and on the ostracod communities of 16 wetlands of the Parco Oglio Sud (Northern Italy). Physical and hydrochemical variables were measured and ostracod samples were collected in different seasons (April, June, August, and October). Most of the considered sites were characterised by high concentrations of nitrogenous compounds due to washing out from cultivated areas, intermittent river flooding and internal recycling. Observed differences in macrophyte communities were consistent with trophic status of waters, with pleustonic forms dominating most degraded areas. Both morphology of valves (by scanning electron microscopy) and anatomy of soft parts were analysed for ostracod species identification. Nineteen ostracod species in five families were found. Two species, Candona weltneri and Pseudocandona compressa, are new records for Italy. Cypria ophthalmica was collected from all sampling sites; other relatively common species were Cypridopsis vidua, Cyclocypris ovum, and Candona weltneri. No clear seasonably was observed in community structure; highest species diversity occurred in June in most of the studied wetlands. The maximum number of species per site was seven, and a maximum of six species was found in a single sample. Ostracod occurrence in relation to environmental factors was examined using Canonical correspondence analysis (CCA). Total alkalinity and pH were the most important variables structuring the species assemblages. The ostracod fauna found in this area was compared to the known distribution of recent non-marine ostracods in Italy, and the validity of published checklists is discussed
Nitrogen and phosphorous budgets during a farming cycle of the Manila clam Ruditapes philippinarum: An in situ experiment
No full text
Relazione tra il ciclo stagionale di Trapa natans L. e la qualità dell’acqua nella Lanca di Po (Villanova d’Arda, Piacenza).
No full textRelazione tra la disponibilità di ossigeno e ferro e la circilazione di solfuri in ambienti lagunari distrofici
No full text
Caratterizzazione di acque, sedimenti e idrofite nella Riserva Naturale Paludi di Ostiglia
No full textSpecies and functional plant diversity in a heavily impacted riverscape: implication for threatened hydro-hygrophylous flora conservation
No full textWetlands play a central role in sustaining biodiversity, especially in landscapes altered by human activities. In overexploited floodplains, alteration of river hydro-morphology has resulted in the progressive disappearance of riparian wetlands. Consequently, several native hydro-hygrophilous plants have experienced a dramatic decline. In this context, artificial shallow water bodies, actively managed for agricultural purposes, could act as potential refuge for relict biodiversity. However, their role in plant conservation has been at present scarcely investigated. In this framework, a floristic study was performed to clarify the patterns of species and functional plant diversity with respect to the origin, hydrology and structural complexity of 60 marginal habitats within the watershed of the Oglio River (3800 km2, Northern Italy). The basin of this regulated river is heavily exploited by intensive agriculture and farming, occurring over 75% of the surface; wetland habitats occupy small surfaces, generally of a few hectares, and are scattered in the territory. The sampled plants were classified by life-growth form and were grouped into four clusters representing the main hydro-hygrophilous functional zones of investigated habitats. An appreciable regional diversity (208 taxa) was found. The typical floristic contingent was composed by lemnids, large helophytes and semihygrophilous opportunist species. Experimental data revealed: (i) the predominance of terrestrial species within shallow aquatic habitats of the Oglio riverscape and (ii) the deterioration of the obligate aquatic plant contingent and the helophyte representativeness in riparian zones. Overall, plant diversity appears to be driven more by the sites origin (natural vs. artificial) and their structural complexity rather than by
their hydrological features (lentic vs. lotic). On the other hand, the present data confirm the important role of the artificial drainage system as temporary valuable habitat for lowland macrophytes
- …
