297 research outputs found
Biomonitoring of lake sediments using benthic macroinvertebrates
The Water Framework Directive (2000/60/EC) is an innovative piece of legislation aimed at protecting the quality of all continental
and coastal waters in Europe through an ecological evaluation of the ecosystems. Since it is widely acknowledged that the
greater the ecological realism the greater the difficulty of its definition, we describe the different uses of benthic organisms as a
tool for assessing the quality of sediment in lakes. We review the responses from single species to the community. We focus on
studies in the laboratory and in the field, and we also critically consider the use of predictive models for these evaluations.
Our discussion of the information collected underlines the importance of the relation between sensitivity of single species and
contaminants. Moreover, the recent approach in developing mechanistic models to predict the response of natural communities
seems to be particularly powerful for community ecology, and we strongly recommend more effort along these lines
Revision of type and non-type material assigned to the genus Orthocladius by Goetghebuer (1940–1950), deposited in the Royal Belgian Institute of Natural Sciences (Diptera: Chironomidae)
Selected type and non-type material belonging to the genus Orthocladius van der Wulp, 1874 (Diptera: Chironomidae) sensu G OETGHEBUER (1940\u20131950), deposited in the Royal Belgian Institute of Natural Sciences (RBINS), originally comprising specimens dry pinned or stored in isinglass, were mounted on microscope slides and re-examined. Other chironomids present in the RBINS collection belonging to other genera were also examined. Fifty slides were prepared and identified to species, or to generic level when the condition of the specimens did not allow species identification. The following types, representing taxa formerly considered as nomina dubia, were examined and the concerned species are stated here as valid: Georthocladius collarti (Goetghebuer, 1941) comb. nov., Georthocladius scaturiginis (Goetghebuer, 1940) comb. nov., Lapposmittia succinea (Goetghebuer, 1942) comb. nov., Orthocladius (Euorthocladius) tolleti Goetghebuer, 1944 (new subgenus placement), Orthocladius (Orthocladius) timoni Goetghebuer & Timon-David, 1939, Pseudorthocladius hockaiensis (Goetghebuer, 1933). Orthocladius (Orthocladius) mitisi Goetghebuer, 1938, previously stated as junior synonym of Orthocladius (Orthocladius) glabripennis (Goetghebuer, 1921), is reinstated as valid species. The following new synonyms are proposed: Georthocladius (Georthocladius) collarti = Parachaetocladius retezati Albu, 1972: 19, syn. nov.; Cricotopus (Paratrichocladius) rufiventris (Meigen, 1830) = Orthocladius franzi Goetghebuer, 1949, syn. nov.; Cricotopus (Paratricho-cladius) skirwithensis Edwards, 1929 = Orthocladius nigritus Goetghebuer, 1938, syn. nov. = Paratrichocladius spiesi Ashe & O\u2019Connor, 2012; Hydrobaenus distylus (Potthast, 1914) = Orthocladius antennalis Goetghebuer, 1944, syn. nov. Lecto-types of Orthocladius collarti Goetghebuer, 1941, Orthocladius antennalis Goetghebuer, 1944, Orthocladius timoni Goetghebuer & Timon-David, 1939, and Orthocladius hockaiensis Goetghebuer, 1933 are designated. Non-type material assigned to Orthocladius was also mounted on slides and identified. Although a list of the non-Orthocladius taxa is also provided, no taxonomic changes are proposed for the latter
Response of chironomid species (Diptera, Chironomidae) to water temperature: effects on species distribution in specific habitats
The response of 443 chironomid species to water temperature was analyzed, with the aim of defining their thermal optimum, tolerance limits and thermal habitat. The database included 4442 samples mainly from Italian river catchments collected from the 1950s up to date. Thermal preferences were calculated separately for larval and pupal specimens and for different habitats: high altitude and lowland lakes in the Alpine ecoregion; lowland lakes in the Mediterranean ecoregion; heavily modified water bodies; kryal, krenal, rhithral and potamal in running waters. Optimum response was calculated as mean water temperature, weighted by species abundances; tolerance as weighted standard deviation; skewness and kurtosis as 3rd and 4th moment statistics. The responses were fitted to normal uni- or plurimodal Gaussian models. Cold stenothermal species showed: i) unimodal response, ii) tolerance for a narrow temperature range, iii) optima closed to their minimum temperature values, iv) leptokurtic response. Thermophilous species showed: i) optima at different temperature values, ii) wider tolerance, iii) optima near their maximum temperature values, iv) platikurtic response, often fitting a plurimodal model. As expected, lower optima values and narrower tolerance were obtained for kryal and krenal, than for rhithral, potamal and lakes. Thermal response curves were produced for each species and were discussed according to species distribution (i.e. altitudinal range in running water and water depth in lakes), voltinism and phylogeny. Thermal optimum and tolerance limits and the definition of the thermal habitat of species can help predicting the impact of global warming on freshwater ecosystems
Diversity and distribution of chironomids (Diptera, Chironomidae) in pristine Alpine and pre-Alpine springs (Northern Italy)
The diversity and distribution of chironomids (Diptera, Chironomidae) were studied in relation to environmental factors in 81
springs under pristine conditions in the Italian Prealps and Alps (Trentino and Veneto, NE-Italy, 46\ub0N, 10-11\ub0E). Each spring was
surveyed once, between May and November, in 2005 or in 2007-2008, within 50 m of the spring\u2019s source (eucrenal). A total of 173
macroinvertebrate samples were collected, in which 26,871 chironomids (including larvae, pupae, pupal exuviae and adults) were
counted. Five subfamilies (Tanypodinae, Diamesinae, Prodiamesinae, Orthocladiinae and Chironominae), 54 genera and 104
species/groups of species were identified. As expected, Orthocladiinae accounted for a large part of specimens (82%), followed by
Diamesinae (10%), Chironominae Tanytarsini (6%) and Tanypodinae (2%). Together the Chironominae Chironomini and
Prodiamesinae contributed less than 0.05% of the fauna. Larvae represented 97.5% of specimens, mostly juveniles (62.6%).
Maximum richness and diversity occurred at intermediate altitudes (ca 900-2100 m a.s.l.). Most taxa were found in a small
proportion of sites, and frequencies declined gradually for more widely distributed species. A high number (67%) of rare (= present
in less than 10% of sites) taxa were found. Three to 27 taxa were identified per spring. The rheocrene/rheo-helocrene springs were
richest in taxa (generally >15 taxa), the mineral spring was poorest, with only three taxa. Most taxa were crenophilous, including
lentic, rheobiontic and bryophilous taxa. A Principal Component Analysis (PCA) was performed including 98 taxa. Axes were
interpreted calculating the correlation coefficients between site scores and 24 environmental factors. The species with the highest
scores were Pseudokiefferiella parva, Corynoneura sp. A, Metriocnemus eurynotus gr., Paratrichocladius skirwithensis and Tvetenia
calvescens. Five clusters of sites were identified with K-means analysis on the basis of the first and second PCA axes and a
Discriminant Analysis was used to detect environmental factors discriminating the clusters: altitude, canopy cover, hydrological
regime, pH, and granulometry as percentage of cobbles and stones. The highly individual nature of springs was highlighted; within
the same river basin, between springs and within a single spring. These results suggest that prudent and conservative land
management should assume that all springs sheltering such unique faunal assemblages need protectio
Introduction into Italy of Gryon pennsylvanicum (Ashmead), an egg parasitoid of the alien invasive bug Leptoglossus occidentalis Heidemann
Leptoglossus occidentalis (Heteroptera, Coreidae), a Nearctic species, was accidentally introduced
into Northern Italy in the late 1990s, from where it has spread throughout Europe. The bug causes
abortion of immature cones of Pinus pinea L., with economic impact on the pine-nut industry. As
part of a pest control research program, the egg parasitoid Gryon pennsylvanicum Ashmead (Hymenoptera,
Platygastridae) was collected from British Columbia, Canada, and legally introduced to a
quarantine climatic chamber in Florence, Italy. The egg parasitoid will be tested against native non target
heteropterans, an environmental impact assessment will be conducted, and a mass rearing
method will be developed if appropriate. The ultimate goal is to release G. pennsylvanicum into Italian
P. pinea forests for classical biological control of L. occidentalis
The First Record of The Subfamily Buchonomyiinae(Diptera, Chironomidae) from Italy
In June and July 2002 mature female pupae and pupal exuviae of B. thienemanni Fittkau were collected from running waters in Northern Italy. This is the first record of the subfamily Buchonomyinae from the Mediterranean region.
The captured pupae show some differences from the European populations: the arrangement of the lateral abdominal setae and the presence of pedes spurii A.
New information about autoecology and geographical distribution of B. thienemanni are given: an earlier emergence was observed in sites characterized by fast, shallow waters and high oxygen content. The species seems to be quite rare in the Mediterranean, and no larvae have been obtained yet.
This paper describes morphology, ecology and distribution of a rare species and is a contribution to the knowledge of freshwater macroinvertebrates as recommended by the Directive of The European Parliament n. 60/2000/CE
Evaluation of basal ganglia haemodynamic changes with perfusion-weighted magnetic resonance imaging in patients with Parkinson's disease
The aim of our study was to assess the regional cerebral blood flow (rCBF) of basal ganglia and thalami in patients with Parkinson’s disease (PD) using perfusion–weighted magnetic resonance imaging (PW–MRI)
Impact of Disease-Modifying Therapies on Gut–Brain Axis in Multiple Sclerosis
Multiple sclerosis is a chronic, autoimmune-mediated, demyelinating disease whose pathogenesis remains to be defined. In past years, in consideration of a constantly growing number of patients diagnosed with multiple sclerosis, the impacts of different environmental factors in the pathogenesis of the disease have been largely studied. Alterations in gut microbiome composition and intestinal barrier permeability have been suggested to play an essential role in the regulation of autoimmunity. Thus, increased efforts are being conducted to demonstrate the complex interplay between gut homeostasis and disease pathogenesis. Numerous results confirm that disease-modifying therapies (DMTs) used for the treatment of MS, in addition to their immunomodulatory effect, could exert an impact on the intestinal microbiota, contributing to the modulation of the immune response itself. However, to date, the direct influence of these treatments on the microbiota is still unclear. This review intends to underline the impact of DMTs on the complex system of the microbiota–gut–brain axis in patients with multiple sclerosis
Benthic macroinvertebrates as indicators in lakes
Benthic macroinvertebrates are considered to be good indicators of the trophic status
of lakes but in the Mediterranean area gaps in knowledge on taxonomical and
autoecological traits of species hinder their potential as indicators. Seventy-eight
Italian lakes were sampled, belonging to 10 types according to morphometrical,
geographical and geological parameters. An unsupervised neural network (SOM analysis)
was carried out using 65 Chironomid and Oligochaete species collected in 1865
samples. he accordance between lake types and species assemblages was tested.
Indicator weight of species was calculated considering their optima for trophic
variables (dissolved oxygen, TP, transparency). A Benthic Quality Index (BQI) and a
weighted diversity index were then calculated to test their potential as indicators of
trophic status of lakes. Alpine, volcanic and large profundal lakes were separated into
diferent clusters, characterized by diferent communities, chemical and morphometrical
parameters. On the contrary, other lake types with similar trophic status were
grouped together, showing similar taxa assemblages. BQI values were in agreement
with the trophic condition of lakes, while the weighted diversity index showed low
values for alpine lakes due to low species numbers
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