1,721,041 research outputs found
Distribution and diet of a recently-established population of Lutra lutra in the Valley of the River Ticino
Full text linkDuring 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 “La Fagiana” 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
Mathematical Models for the Comprehension of Chemical Contamination into the Hive
No full textHoneybees are very sensible organisms and their vulnerability toward chemical pollution is an priority environmental issue. In this chapter the importance and the fundamental of a mathematical model able to predict the fate of chemicals into the hive is described. The ‘Hive model’ presented here is able to consider different contamination pathways: from inside the hive via pesticide treatments against bee pests, or from outside, by means of the eventual contamination present in nectar, pollen, resin, water, air or vegetation. The input parameters of the model are the physical-chemical properties of the compound and the major characteristics of the hive ecosystem, from which it calculates contamination residues in bee products (honey, pollen, royal jelly, wax and propolis) over time. The model can be applied to all non ionic chemicals with a measurable vapour pressure (volatile or semi-volatile compounds). The model was validated with contamination data in bees, wax and honey following tau-fluvalinate application in two experimental hives. The comparison between measured and modelled data over a period of six months was very good. Even if more experimental data should be provided for a better calibration of the model, it seems to correctly quantify the main contamination pathways from outside and within the hive
Phytosociology, preferences and floristic mapping of the most appreciate species by Apis mellifera and other Apoidea
No full textThe alteration of natural and rural landscapes of northern Italy, caused by the broad urbanization and the intensive use of agricultural lands, has led to a reduction in the nectariferous species with the depletion of the food resources available and necessary for the survival of the bees. The existence of architectural barriers determined by human settlements, and the reduction in cultivated areas of nesting sites for wild bee species often alters and obstacles bee movements in the areas in search of the food source. The impact of these factors is extremely variable in relation to the bee-species studied, Apis mellifera L. or other social or solitary bees. In the case of A. mellifera, numerous factors should be considered and they imply both the survival of the colony and the productive capacity in terms of honey produced. The analysis of the territory is therefore fundamental, supported by phytosociological studies, use of databases related to land use and apiaries position as a proxy indicator of territorial suitability for the creation of maps aimed at verifying the potential beekeeping of the territories surrounding the hives. It is evident how these maps, obtained with the support of Web & Mobile App and GIS, become a scientific tool for the study and design of environmental improvement interventions and for crop management in support of the honey bees. With regard to this last aspect, the results of some specific studies on nectariferous species, potentially introduced in association with other crops to support bees in times of difficulty, are reported. Furthermore, in the panorama of highly anthropic environments, botanical gardens and urban parks, rich in numerous species that alternate blossoming period to improve the aesthetic purpose, can be used as open-air laboratories for the study of the relationships among bee-species, environment, floral species, and flowering. Through the study of the flower-bee network, it is possible to identify the most suitable species to support both A. mellifera and/or other species of Apoidea, both generalists and specialists. It is also possible to deepen the relationships that correlate the flower traits to the different species of bee present considering the interaction between the morphology/bioethology of the bee and the botanical characteristics
Anthropogenically altered trophic webs : alien catfish and microplastics in the diet of Eurasian otters
No full textWith the aim of examining how Eurasian otters (Lutra lutra) face human-mediated environmental alterations, we assessed their diet by spraint analysis on the River Ticino (NW Italy), where this mustelid has been reintroduced in 1997. From March 2016 to March 2017, a total of 101 spraints was found in 50% of 32 sampling stations (mean length ± SD = 567 ± 263 m). Fish formed the bulk of otter diet (95% of the estimated mean percent volume, mV%). Cyprinids were the most preyed fish (mV% = 44.9), followed by European catfish Silurus glanis (mV% = 24.9%) and eel Anguilla anguilla (mV% = 8.5). Introduced European catfish is an invasive species, which can deeply alter the composition and structure of local fish communities and accumulate large amounts of metals and pollutants through the trophic chain. We also recorded for the first time microplastic particles (< 5 mm) in otter spraints. Suspected particles were analysed by Fourier transform infrared (FTIR) spectroscopy and two polymer types were identified: polyethylene terephthalate (PET) and polyamide (PA). Although otters showed to be able to adapt to anthropogenic changes, these results point out new potential threats to otter conservation and ask for further studies
Predicting pesticide fate in the hive (part 2): development of a dynamic hive model
No full textA new hive model is proposed for the assessment of the distribution and fate of pesticides in the hive ecosystem. Based on the chemical used, the model draws a dynamic picture of pesticide contamination in the hive, calculating contamination trends and concentration levels in the various hive components (e.g. bees, wax and honey). The proposed model is validated using empirical data on tau-fluvalinate residues in bees, wax and honey. It predicts with good approximation both the trends over time and the contamination levels of the pesticide in the various hive components. We have developed most of the parameters and equations used in this model. Although they will require further experimental testing, they provide realistic predictions that are consistent with the experimental data. The proposed model is a useful tool for predictive purposes and improves our understanding of contamination phenomena in the hive
Predicting pesticide fate in the hive (part 1): experimentally determined τ-fluvalinate residues in bees, honey and wax
No full textτ-Fluvalinate residues in bees, honey and wax were measured in two experimental hives treated with Apistan to test a multi-compartmental predictive model. Pesticide residues were monitored for 30 days after treatment in bees and for up to 180 days in honey and wax. Concentrations ranged between 14 and 160 ng g−1 f.w. in bees and between 98 and 1630 ng g−1 in wax, while no residues were detected above the analytical limit (2.5 ng g−1) in honey. τ-Fluvalinate residues are discussed in the context of a survey of data from the literature on other pesticides (bromopropylate, coumaphos, malathion and amitraz). This data review
shows that residues of the same compound exhibit extremely high variability within the same matrix. This finding underlines the importance of developing predictive tools for both post-treatment analysis and a priori
evaluation of the possible contamination effects of pesticides depending on the mode of applicatio
Quantitative inter-specific Chemical Activity Relationships of Pesticides in the Acquatic Environment
No full textInter-species correlations could be a useful tool for predicting toxicity and for establishing sensitivity ratios among species. In this paper, quantitative inter-specific chemical activity relationships (QICAR) for aquatic organisms were developed to verify if such an approach could be utilised for estimating toxicological data when no other information is available. Inter-specific toxicity relationships on fish, Daphnia and algae were performed for pesticides considering a large data set (more than 600 compounds) and grouping the data either on a functional (herbicides, fungicides and insecticides) or chemical class base. Good correlations were found between several fish species and they were improved by excluding, from the data set, highly specific compounds such as organophosphorus insecticides. Relationship between fish (rainbow trout) and Daphnia was significant for the whole data set, but clearly improves if congeneric classes of pesticides are considered. The most significant results were found for azoles (fungicides) and for all data set of pesticides with the exclusion of organophosphorus and carbamate insecticides. As expected, toxicity on algae does not correlate either with fish or with Daphnia on the whole data set, but excluding the classes acting specifically toward one organism (insecticides and several classes of herbicides), good relationships were found. The analysis of the data permits the conclusion that the specificity in the mode action of pesticides is the key parameter for expecting or not inter-specific relationships. By the relative specificity of action of a group of compounds towards two species, the probability of obtaining a QICAR for this group can be derived. In general, compounds acting with the same level of specificity towards two different species, have a higher probability of showing inter-specific relationships and the lower the specificity of the mode of action of the compounds (e.g. narcotics or less inert chemicals), then the stronger are the relationships
Coumaphos distribution in the hive ecosystem : case study for modeling applications
No full textPesticides are currently used inside hives, against the honeybee parasite Varroa destructor, producing unwanted contamination effects. To assess the distribution and fate of one of these pesticides (coumaphos), two experimental hives were treated with Perizin (the commercial product containing the active ingredient coumaphos). Samples of honey, wax, pollen, adult bees and larvae taken before treatment and up to 104 days afterwards, showed diffuse contamination. Wood hedges and wax bridges, where the pesticide solution was applied, were analysed as well. A mass balance was calculated, yielding a recovered amount of around 60% just after treatment and 38% 1 month later. Directly contaminated surfaces and wax contained the highest amount of residues. Wax and honey contained different amounts (10, and 0.1% respectively) but both retained residues for long time. Bees ingest most of the product just after treatment, then rapidly eliminate it by metabolism, advection and deposition processes. On the basis of analytical results, a simple model (level I of the fugacity model) was applied to the hive system for different pesticides (coumaphos, malathion, fluvalinate and bromopropylate). Predicted concentrations in wax and honey were compared with those measured, indicating the good predictive capability of this approach
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