297 research outputs found
Distribution and diet of a recently-established population of Lutra lutra in the Valley of the River Ticino
During the 20th century, the European otter (Lutra lutra) has dramatically declined in central and southern Europe because of hunting, destruction of riparian habitat and chemical pollution. In Italy, few population have survived in the most remote areas of the southern Apennines, where recent studies have recorded an unexpected recovery. In the valley of the River Ticino, a pair of otters was reintroduced in 1997 from a breeding centre (Cameri) located in Piedmont. A further pair possibly escaped before the end of the century. Additionally, during floods in 1991 and 1993 respectively, a pair and a cub and a pair with two sub-adults escaped from their breeding enclosure \u201cLa Fagiana\u201d on the Lombardy side of the river. In spring 2016 an otter survey was carried out with the aim of drawing a picture of the current distribution of the species in the area. By surveying 600 m long transects, otter spraints were found in 8 different stations, between Cameri and Parasacco towns, corresponding to about a 35 km section of the river. Sprainting sites were mainly found inside the weave of meanders, on streams, canals and oxbow lakes, rather than on the main course of the river. All collected otter spraints were stored in silver paper, labelled and frozen until diet analysis. Each spraint was soaked for 12 hours in a solution of hydrogen peroxide and then placed into sieves with 0.5 mm wide meshes, and washed by a water jet. Fish remains were identified from their vertebrae, jawbones and scales, using personal collections and the keys of different authors. Amphibians were identified by the keys of Di Palma and Massa (1981), whilst the telson, chelae and thoracopods were the main diagnostic features for crustaceans. Results were expressed as percent frequency of occurrence F%, percent relative frequency of occurrence FR%, estimated per cent volume V% and per cent mean volume Vm%. In the area, fish - mainly trout (Vm%=21.4), redfin perch (Vm%=17.3), Eurasian minnow (Vm%=13.6) and South European nase (Vm% =9.4) -, formed the bulk of otter diet. Fresh faecal samples were preserved in 96% ethanol and frozen for genetic analyses with the aim of assessing the size and kinship for the otter population in the valley
Reassessing the biostratigraphy and the paleobathymetry of the Gonfolite Lombarda Group in the Como area (northern Italy)
Calcareous nannofossil and foraminiferal analyses have been carried out on outcrops from the type-area of the Gonfolite Lombarda Group (Como, northern Italy). In these marine fine- to coarse-grained clastics, rapidly accumulating at the southern front of the uprising Alpine range during the Oligo-Miocene, a scarce, but reliable, sequence of calcareous nannofossil events has been observed, allowing to refine the previous age assignments. Planktonic foraminifera were found to be extremely rare and provided limited biostratigraphic information. The Villa Olmo Conglomerate and the Chiasso Formation contain the Last Occurrence (LO) of Sphenolithus distentus and the First Occurrence (FO) of Triquetrorhabdulus carinatus, which are characteristic of the nannofossil zones NP24 and NP25 (Chattian), respectively. The lower part of the Como Conglomerate was deposited during the zone NP25, whilst the upper part of the Como Conglomerate straddles the Chattian/Aquitanian boundary in zone NN1. The deposition of the Prestino Mudstones also occurred during zone NN1. However, the upper part of this formation has been dated as Burdigalian during nannofossil zone NN2. The deposition of the upper part of the Val Grande Sandstone has been assigned to the NN3 zone owing to the presence of the taxon Sphenolithus belemnos, which is restricted to NN3. The upper part of the investigated section is characterized by the deposition of the Lucino Conglomerate and its fine-grained members (Lucinasco and Lurate Caccivio Mudstones). The Lucinasco Mudstones have been dated as late Burdigalian corresponding to zone NN4, whilst the overlying Lurate Caccivio Mudstones were deposited during the Langhian part of the zone NN5, based on the presence of S. heteromorphus and the absence of H. ampliaperta. On the whole, the base and the top of the outcropping Gonfolite Lombarda Group result from our study to be younger than hitherto proposed, allowing to resolve certain previous conflicts with the few radiometric dates available for clasts from the Gonfolite Lombarda Group. The depth of deposition was upper bathyal during the Chattian and the Aquitanian and shallowed to neritic during the deposition of the Langhian Lurate Caccivio Mudstones
The otter population of the River Ticino (N Italy) 20 years after its reintroduction
On the River Ticino (Piedmont and Lombardy regions, N Italy), the Eurasian otter Lutra lutra
became extinct in the 1980s and was reintroduced in 1997. Since then, the status of the
reintroduced population has been assessed only occasionally, in 2008 and 2010. Between
2016 and 2018, we conducted an extensive survey for otter signs along the whole Italian
stretch of the River Ticino, following the \u2018Standard Method\u2019 for otter surveys. In 2016\u20132017,
we found 101 spraints (mean marking intensity: 0.40 spraints/100 m), spread over a 97-km
long stretch of the river. In 2018 only five spraints were collected, the two furthermost
marking sites being 32 km apart. Genotyping of nDNA extracted from 21 faecal samples
enabled the identification of six different individuals.
The surveys led to drawing a reliable picture of otter distribution and population size,
with evidence of otter occurrence on a longer than previously recorded stretch of the river.
The results of the 2018 survey suggest that stochastic factors may still threaten the survival
of reintroduced otters and would suggest a reinforcement of the population is required to
increase its genetic diversity
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End-Triassic calcification crisis and blooms of organic-walled 'disaster species'
The TriassicâJurassic (TâJ) mass-extinction event is marked by isotope anomalies in organic (δ13Corg) and carbonate carbon (δ13Ccarb) reservoirs. These have been attributed to a (rapid) 4-fold rise in pCO2 as a result of massive flood basalt volcanism and/or methane hydrate dissociation. Here we examine the response of marine photosynthetic phytoplankton to the proposed perturbation in the carbon cycle. Our high-resolution micropalaeontological analysis of TâJ boundary beds at St Audrie's Bay in Somerset, UK, provides evidence for a bio-calcification crisis that is characterized by (1) extinction and malformation in calcareous nannoplankton and (2) contemporaneous blooms of organic-walled, green algal 'disaster' species which comprise in one case > 70% of the total palynomorph fraction. Blooms of prasinophytes and acritarchs occur at the onset and in association with a prominent negative shift in δ13Corg values close to the first appearance of the Early Jurassic ammonite Psiloceras planorbis. Across the same interval we obtained palaeotemperature and palaeosalinity estimates from oyster low-Mg calcite based on Mg/Ca, Sr/Ca and δ18O records. The results of our palynological and geochemical analyses strongly suggest that shallow marine basins in NW Europe during this period became salinity stratified, inducing anoxic conditions. The TâJ boundary event shows similarities with the PermianâTriassic (PâT) mass-extinction event, which was also marked by extensive flood basalt volcanism, negative excursions in carbon isotope records, a bio-calcification crisis, the development of shallow-marine anoxia and mass abundances of acritarchs in the Early Triassic. This leads us to suggest that the proliferation of green algal phytoplankton may be symptomatic of elevated carbon dioxide levels in the atmosphere and oceans during mass-extinction events
Predicting PCB concentrations in cow milk: validation of a fugacity model in high-mountain pasture conditions
A fugacity model reported in the literature was applied to a high - altitude pasture in the Italian Alps. The model takes into account three compartments (digestive tract, blood and fat tissues) in unsteady-state conditions using food as the contamination source. Disregarding biotransformation inside cow tissues, the predicted concentrations of 14 polychlorinated biphenyls (PCBs) in milk were in good agreement with the observed data, especially for congeners known for their resistance to biotransformation (e.g., CB-138 and 153). In contrast, the predicted concentrations were clearly overestimated for congeners with high biotransformation susceptibilities.
Therefore data measured in milk and faeces were used to calculate the first-order-biotransformation rate constants in dairy cows. The PCB absorption efficiency observed for pasture conditionswas lower than that observed in the cowshed. The final version of the model included biotransformation and observed PCB absorption andwas able to predict PCB concentrations in cow milkwith mean differences between the predicted and measured data below \ub120% for most congener
Gli echinodermi come modelli per lo studio di Distruttori Endocrini: un approccio integrato
Gli echinodermi rappresentano dei validi modelli sperimentali nell\u2019ambito dell\u2019ecotossicologia marina. Essi infatti sono organismi bentonici a diretto contatto con potenziali fonti di xenobiotici e offrono un ampio range di processi biologici utili per questo tipo di approccio. In questo lavoro sono presentati i risultati pi\uf9 significativi ottenuti nel nostro laboratorio utilizzando questi organismi come modelli per lo studio degli effetti di potenziali Distruttori Endocrini (ED). Sono stati presi in esame due diverse specie di echinodermi, il riccio di mare Paracentrotus lividus e il crinoide Antedon mediterranea, e due diversi aspetti della loro fisiologia, la biologia riproduttiva e lo sviluppo rigenerativo, rispettivamente. Esemplari adulti di entrambe le specie sono stati esposti a diversi ED, potenzialmente in grado di interferire con gli ormoni sessuali. Le concentrazioni utilizzate erano comparabili a quelle ambientali. La ricerca si \ue8 basata su un approccio multidisciplinare che ha previsto analisi morfologiche, chimiche e biochimiche. I risultati ottenuti hanno evidenziato la capacit\ue0 di questi composti di interferire con diversi parametri quali la crescita rigenerativa, il pattern istologico e il diametro delle uova prodotte, sebbene lo specifico meccanismo d\u2019azione sia ancora da chiarire. Infatti, nel caso di P. lividus, la somministrazione diretta di ormoni sessuali, quali l\u2019estradiolo, non produce effetti significativi sulla biologia riproduttiva dell\u2019animale. Nel complesso i risultati ottenuti sottolineano sia l\u2019importanza di utilizzare modelli alternativi nei test ecotossicologici sia la necessit\ue0 di approfondire maggiormente la fisiologia di base degli organismi modello
Multimodal imaging and diagnosis of myopic choroidal neovascularization in Caucasians
To investigate myopic choroidal neovascularization (mCNV) by fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), near-infrared (NIR) reflectance, and autofluorescence (AF)
Multiple Routes of Pesticide Exposure for Honey Bees Living Near Agricultural Fields
Populations of honey bees and other pollinators have declined worldwide in recent years. A variety of stressors have been implicated as potential causes, including agricultural pesticides. Neonicotinoid insecticides, which are widely used and highly toxic to honey bees, have been found in previous analyses of honey bee pollen and comb material. However, the routes of exposure have remained largely undefined. We used LC/MS-MS to analyze samples of honey bees, pollen stored in the hive and several potential exposure routes associated with plantings of neonicotinoid treated maize. Our results demonstrate that bees are exposed to these compounds and several other agricultural pesticides in several ways throughout the foraging period. During spring, extremely high levels of clothianidin and thiamethoxam were found in planter exhaust material produced during the planting of treated maize seed. We also found neonicotinoids in the soil of each field we sampled, including unplanted fields. Plants visited by foraging bees (dandelions) growing near these fields were found to contain neonicotinoids as well. This indicates deposition of neonicotinoids on the flowers, uptake by the root system, or both. Dead bees collected near hive entrances during the spring sampling period were found to contain clothianidin as well, although whether exposure was oral (consuming pollen) or by contact (soil/planter dust) is unclear. We also detected the insecticide clothianidin in pollen collected by bees and stored in the hive. When maize plants in our field reached anthesis, maize pollen from treated seed was found to contain clothianidin and other pesticides; and honey bees in our study readily collected maize pollen. These findings clarify some of the mechanisms by which honey bees may be exposed to agricultural pesticides throughout the growing season. These results have implications for a wide range of large-scale annual cropping systems that utilize neonicotinoid seed treatments
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