The drift of Rotifers in the River Adige: Preliminary communication

Microfaunal communities in three lowland rivers under differing flow regimes

“…In this study, there was little difference between the plankton communities collected from main river channel and slackwaters, indicating that there was an exchange of animals between the two planktonic habitats. These population similarities may be driven by variations in discharge and changing water levels moving animals into and out of these areas (Braioni, 1981;Saunders & Lewis, 1989;Speas, 2000;Schiemer et al, 2001;Keckeis et al, 2003), however, in this study, correlation between the percentage similarity of the two plankton communities and discharge did not indicate that discharge was the primary cause of population mixing. It is more likely that active movement of animals between the two habitats is occurring.…”

“…Drift is a characteristic of many invertebrate taxa and allows animals to recolonise newly inundated slackwaters following periods of high flows (Speirs & Gurney, 2001). Studies of microfaunal drift have suggested that animals found regularly in the drift are not likely to be benthic in origin (Campbell, 2002) but may be derived from the plankton of still water zones along the river edge (Braioni, 1981). In this study, there was little difference between the plankton communities collected from main river channel and slackwaters, indicating that there was an exchange of animals between the two planktonic habitats.…”

Biodiversity down by the flow: new records of monogonont rotifers for Italy found in the Po River

“…In addition to that, 58 more species were recorded by subsequent works (Fontaneto & Melone 2003;Rossetti et al 2003;Fontaneto et al 2004;De Smet 2007;Fontaneto et al 2008;Bertani et al 2009;De Smet 2009;Rossetti et al 2009). In Italy, extensive field research has traditionally been carried out on monogonont rotifers in lentic ecosystems, while a comparatively smaller amount of studies have focused on lotic communities (e.g., Braioni 1981;Ferrari et al 1989). Nevertheless, rotifers typically represent the dominant group in terms of abundance among metazoan plankton in large rivers, because of their fast generation times (Lair 2006).…”

“…Moreover, the hydrogeomorphic complexity of fluvial systems often provides an extremely diverse array of substrates and microhabitats that favours the development of rich benthic-periphytic assemblages (Ricci & Balsamo 2000;Thorp et al 2006). These latter may be subjected to dislodgement and resuspension, especially during high water phases, further enriching the truly planktonic community (Braioni 1981;Schmid-Araya 1998). Accordingly, assemblages found in the main current of rivers typically derive from a mixture of planktonic organisms and inocula from benthic and periphytic substrates, inshore retention zones, backwaters, periodically inundated floodplain habitats and tributaries.…”

Functional Evaluations in the Monitoring of the River Ecosystem Processes: The Adige River as a Case Stu

“…The translation of quantitative results into five quality classes, more suitable for biomonitoring, was carried out by a double-entry table. The qualitative score of excellent, medium, or poor for every variable evaluated-variety, % plankton species, plankton species dominance, density, biovolume, Diversity index (H'), Maximum Diversity (H max), Eveness index (J), Dominance index (D), Saprobic index value, Rotifera loads, inorganic and organic loads, chlorophyll a, conductivity, pH, cloudiness, sedimentary solids, total dry weight, total suspended solids, stationary residuum, volatile solidswas indicated according to correspondence to the literature data related to the season and the hydrological variability [15,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35]. The following criteria were taken into account when the self-purifying capacity of the lowland course of the Adige River was classified according to quality class: the increase, decrease, and constancy of the loads of N and P flowing through the three stations; and the quantity of nutrients released by the sediments.…”