Settling distances of benthic invertebrates in a sediment mobilization simulation in semi-natural flumes

Drift time and distance depend on the ability of the drifting invertebrates to alter their body posture or by swimming, and these behaviors may change according to the local hydraulic environment, resulting in different distances travelled before exiting the drift. Such drift and settlement mediated invertebrate movement determine dispersal processes and ultimately generates distribution patterns within streams. We conducted an experiment in an open-air, artificial flume system directly fed by an Alpine stream, where we disturbed the sediment in the flumes, inducing catastrophic drift in the benthic community, and then assessed the settlement distances of benthic invertebrates. For each flume, we collected drift samples by disturbing the substrate at 1.5 m intervals, at increasing distance from the downstream end, for a total of 7 disturbances and a maximum settling distance of 10 m in each flume, with five replicates (i.e., five flumes) for each disturbance. The disturbances induced a massive catastrophic drift in Ephemeroptera, Plecoptera and Trichoptera, always higher than the behaviorally-occurring basedrift. The Settling Index calculated over the total drift collected at each distance increased with increasing distance, and after 10 m, 90% of the drifting animals had settled. Evenness and taxa richness progressively decrease with increasing settling distance. All drifting taxa were represented mainly by young instars. We used the drift collected at 1 m from the disturbance to standardize the remaining samples, based on the assumption that 1 m is not a distance long enough to allow animals to settle at that water velocity. We calculated the percentage of possible drifters which settled by computing a Settling Index for each taxon. The drifting taxa listed by decreasing Settling Index scores were Epeorus sp., Rhithrogena semicolorata, Isoperla spp., Sericostoma spp., Ecdyonurus spp., Nemoura spp., Leuctra spp., Baetis spp., Hydropsyche spp., Rhyacophila spp. We have shown, in accordance with numerous other studies, that entrained EPT nymphs travel only short distances before returning to the substratum, and that the actual distance travelled while drifting and the total time spent in drift varies between species. The results of this study can provide suggestions to assess taxon-specific availability to colonization which generates distribution patterns within streams and, on a smaller scale (i.e., flume simulations), our results can be extrapolated to other studies conducted in artificial flumes, or to support evidences from field studies.</p

Ephemeroptera, Plecoptera and Trichoptera in springs in Trentino (south-eastern Alps)

Within the CRENODAT project (Biodiversity assessment and integrity evaluation of springs of Trentino - Italian Alps - and longterm ecological research, 2004-2008) we studied a total of 90 springs in Trentino (south-eastern Alps, Italy), 75 of which were used for statistical analysis. The springs were grouped into seven different types and represented all the available lithologies in the study area. Macrozoobenthos (Ephemeroptera, Plecoptera and Trichoptera; EPT) was collected from stones, bryophytes and sediments. We investigated which physical, chemical or environmental features were important in determining EPT assemblage metrics at sites, by calculating the Shannon-Wiener diversity index, and applying a one-way ANOVA test, ANOSIM and SIMPER analyses. Statistical results highlighted the island character of the springs, each spring having its specific history and abiotic characteristics, which select for unique community patterns. For the faunistic analyses, we considered all springs where EPT taxa were recorded; a total of 88 taxa. Highest species richness was recorded among the Trichoptera, followed by the Plecoptera and Ephemeroptera, with 52, 30 and 6 taxa respectively. Fifteen Trichoptera and three Plecoptera species were recorded as new for the Autonomous Province of Trento. Our results confirm that, in the harsh environment of the Alps, the mild and stable ecological conditions that characterize spring-fed brooks contribute to maintaining and enhancing the regional biodiversity. Springs act as refuge areas for stream biota, providing more favourable conditions during spates or droughts (common in Alpine headwaters), or for particular stages of the insect life cycles. Springs also provide specific habitats for strictly crenobiontic species

The Tagliamento River: A model ecosystem of European importance

In NE Italy is a remarkable floodplain river that retains the dynamic nature and morphological complexity that must have characterized most Alpine rivers in the pristine stage. This river system, the Fiume Tagliamento, constitutes an invaluable resource not only as a reference site for the Alps, but as a model ecosystem for large European rivers. The Tagliamento has a number of attributes that have not been given due consideration in river ecology: (i) an immense corridor of more than 150 km2 that connects the land and the sea and two biomes, the Alps and the Mediterranean; (ii) unconstrained floodplain segments characterised by a dynamic mosaic of aquatic/terrestrial habitats; and (iii) a large number of vegetated islands (ca. 700). We believe it is critical to understand the functional roles of these endangered attributes in order to effectively engage in river conservation and management programmes. The Tagliamento River in Italy offers the rare opportunity to investigate natural processes at a scale that can be studied almost nowhere else in Europ

CAPACITAÇÃO EM TÉCNICAS DE CITOPATOLOGIA DA MUCOSA ORAL E APLICABILIDADE DE SUA CLASSIFICAÇÃO NA PREVENÇÃO DO CÂNCER NA POPULAÇÃO DISCENTE DO INSTITUTO BIOMÉDICO DA UNIRIO, RIO DE JANEIRO, RJ.

As lesões de mucosa oral são negligenciadas pela sociedade médica e observa-se uma deficiência da formação acadêmica no que tange a capacidade do profissional de identificar lesões malignas e pré-malignas, que são causas importantes de morbimortalidade na população¹. Objetivou-se a capacitação de estudantes de Medicina quanto à identificação e manejo de lesões comuns da mucosa oral, neoplásicas ou não, além do traçado do perfil da população atendida com lesões e a orientação dos casos sugestivos de lesões de risco. Palavras-chave: Citopatologia; Prevenção de câncer; População discent

Multiple drift responses of benthic invertebrates to hydropeaking waves

Sudden instream releases of hypolimnetic water from hydropower plants (i.e., hydropeaking) can cause abrupt temperature variations (i.e., thermopeaking), typically on a daily basis. The propagation of the discharge and thermal waves are asynchronous, causing the benthic community to undergo two distinct but consecutive impacts. Invertebrates are known to respond to sudden increases in discharge with catastrophic drift, and recently have been shown to respond to sudden changes of temperature with drift, which is probably behavioral. Due to the decoupling of the discharge and thermal waves, catastrophic and behavioral drift can occur as distinct events. We analyzed the induction of drift in benthic invertebrates caused by a hydropeaking wave followed by a thermopeaking wave, in two open air flumes directly fed by an Alpine stream. The slight but abrupt increase in discharge caused a maximum 28 and 24-fold peak increases in drift in the two flumes, and the abrupt decrease in temperature caused an increase of 36 and 198-fold in the same flumes. In both flumes drift propensity increased during hydropeaking and thermopeaking simulations, and was higher during the latter

Distribution and biometry of native and alien crayfish in Trentino (Italian Alps)

To fill the existing gaps in the knowledge of the crayfish species distribution in Trentino region (North-East Italy), we surveyed fourteen lakes, six ponds and sixty-nine creeks and streams in 2010-2012. We recorded four populations of the invasive alien species Orconectes limosus in four lakes and twenty of the native Austropotamobius pallipes complex from four lakes, three ponds and thirteen creeks; three of these populations went extinct during the three years of our survey. Crayfish populations were monitored in spring, summer and early autumn, to assess the distribution, density and seasonal dynamics of the two species. Statistical analysis of morphometric data showed differences in body size and growth rates among sampling sites, possibly related to local environmental factors, with higher growth rates in males of both species; A. pallipes grew faster in creeks than in lakes. The extinction of twenty-two native populations of A. pallipes complex in the last century was likely due to habitat modifications, in particular to the loss of riparian habitat, in few cases to overfishing, and, more recently, to the spread of alien species and the related transmission of their parasite Aphanomyces astaci. Some populations of A. pallipes complex were infested with the parasite Thelohania sp., and only one population with ectosymbiotic Branchiobdellida. In Trentino, small creeks with well developed riparian vegetation and good hydromorphological conditions, flowing through mountain slopes, can represent potential refuge and recruitment areas for of A. pallipes complex, without significant management intervention, although a sustainable management of piedmont water bodies would allow preserving or increasing the number and density of the relict populations