11 results on '"Rossi, Loreto"'
Search Results
2. Association of riparian features and water chemistry with reed litter breakdown in a volcanic lake (Lake Vico, Italy)
- Author
-
Costantini, Maria Letizia, Rossi, Loreto, Scialanca, Fabrizio, Nascetti, Giuseppe, Rossi, David, and Sabetta, Letizia
- Published
- 2007
- Full Text
- View/download PDF
3. Role of fungal patchiness on vegetal detritus in the trophic interactions between two brackish detritivores, Idotea baltica and Gammarus insensibilis
- Author
-
Constantini, M. Letizia and Rossi, Loreto
- Published
- 1995
- Full Text
- View/download PDF
4. 32Phosphorus transfer in systems of fish and amphipods exploiting detritus particles
- Author
-
Costantini, M. Letizia and Rossi, Loreto
- Published
- 1995
- Full Text
- View/download PDF
5. Autochthonous and allochthonous plant contributions to coastal benthic detritus deposits: a dual-stable isotope study in a volcanic lake
- Author
-
Rossi, Loreto, Costantini, Maria Letizia, Carlino, Pasquale, Antonella, Lascio, DI LASCIO, Antonella, and David, Rossi
- Subjects
volcanic lake ,chemistry.chemical_classification ,detritus sources ,Detritus ,c and n isotopic ratios ,isosource mixing model ,land cover ,lake-bottom slope ,Ecology ,δ13C ,Stable isotope ratio ,Geochemistry ,δ15N ,Aquatic Science ,chemistry ,Benthic zone ,Plant cover ,Organic matter ,Ecology, Evolution, Behavior and Systematics ,Geology ,Water Science and Technology ,Isotope analysis - Abstract
The high numbers of primary producers represent multiple sources of organic matter accumulating onto lake bottoms. The difficulty of distinguishing the relative contribution to the mixture presents considerable challenges to the analysis of these organic deposits. In this study, dual-stable isotope analysis and IsoSource model were used to identify allochthonous and autochthonous components of detritus deposits (Particulate Organic Matter: POM) at two different bottom slope sites of a volcanic lake (lake Bracciano). Experiments were carried out to calibrate IsoSource on constructed plant mixtures and assess changes in isotope ratios during plant decomposition. IsoSource satisfactorily discriminated the constructed mixture sources with a few exceptions. Changes in isotopic enrichment during decomposition were low, and thus did not represent a confounding variable in the isotopic analysis. By contrast, chemical and geological differences of the study sites were associated with differences in plant δ13C and δ15N values (more than 2‰ within single plant species). At both sites, the isotopic signals of POM fell between polygons delineated by source end members with an evident shift of δ13C toward allochthonous sources. POM amount and diversity were greater at the flatter bottom site, where allochthonous contributions were larger than at the other site. In particular, IsoSource ranked species contributions as follows: A. glutinosa > P. australis > A. donax > S. alba > P. nigra > the benthic macroalga Chara sp. at the first site, and A. glutinosa > P. nigra > the aquatic macrophyte C. demersum at the latter. The composition of littoral POM was determined by allochthonous sources in proportion to their relative abundances (as percent land cover) with differences between sites due to bottom slope.
- Published
- 2010
6. Predator and detritivore niche width helps to explain biocomplexity of experimental detritus-based food webs in four aquatic and terrestrial ecosystems.
- Author
-
Rossi, Loreto, di Lascio, Antonella, Carlino, Pasquale, Calizza, Edoardo, and Costantini, Maria Letizia
- Subjects
PREDATORY animals ,BIOCOMPLEXITY ,DETRITUS ,FOOD chains ,AQUATIC ecology ,BAYESIAN analysis - Abstract
In the study of food webs, the existence and explanation of recurring patterns, such as the scale invariance of linkage density, predator–prey ratios and mean chain length, constitute long-standing issues. Our study focused on litter-associated food webs and explored the influence of detritivore and predator niche width (as δ 13 C range) on web topological structure. To compare patterns within and between aquatic and terrestrial ecosystems and take account of intra-habitat variability, we constructed 42 macroinvertebrate patch-scale webs in four different habitats (lake, lagoon, beech forest and cornfield), using an experimental approach with litterbags. The results suggest that although web differences exist between ecosystems, patterns are more similar within than between aquatic and terrestrial web types. In accordance with optimal foraging theory, we found that the niche width of predators and prey increased with the number of predators and prey taxa as a proportion of total taxa in the community. The tendency was more marked in terrestrial ecosystems and can be explained by a lower per capita food level than in aquatic ecosystems, particularly evident for predators. In accordance with these results, the number of links increased with the number of species but with a significantly sharper regression slope for terrestrial ecosystems. As a consequence, linkage density, which was found to be directly correlated to niche width, increased with the total number of species in terrestrial webs, whereas it did not change significantly in aquatic ones, where connectance scaled negatively with the total number of species. In both types of ecosystem, web robustness to rare species removal increased with connectance and the niche width of predators. In conclusion, although limited to litter-associated macroinvertebrate assemblages, this study highlights structural differences and similarities between aquatic and terrestrial detrital webs, providing field evidence of the central role of niche width in determining the structure of detritus-based food webs and posing foraging optimisation constraints as a general mechanistic explanation of food web complexity differences within and between ecosystem types. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
7. Trophic attractiveness for soil fauna of residues of Bt and near-isogenic maize: a C and N stable isotope-based study.
- Author
-
Sporta Caputi, Simona, Rossi, Loreto, Pons, Xavier, Careddu, Giulio, Calizza, Edoardo, and Costantini, Maria Letizia
- Subjects
- *
SOIL animals , *PLANT residues , *PEST control , *PREY availability , *FOOD chains , *INSECTICIDES , *CORN - Abstract
Genetically modified (GM) crops are considered a good way to reduce insecticide use and the presence of certain agricultural pests, thus improving food and environmental safety. Nevertheless, effects of GM plant residues on the soil food web are still poorly understood. Zea mays L., enriched with a gene from Bacillus thuringiensis Berliner subsp. kurstaki (Bt) as a defence against the maize borer, is widely cultivated. In this study, we explored the invertebrate food webs associated with residues of Bt and non-Bt maize, respectively represented by DKC6575, with a Cry1Ab transgene (event MON810), and its near-isogenic Tietar variety, in a five-month field experiment. C and N stable isotopes and Bayesian mixing models were used to assess trophic niche metrics and track nutrient flows from maize residues and weeds occurring in maize crops to invertebrate detritivores and predators. While there were no initial differences in the structural components of maize residues between varieties, after five months of exposure in the field, the lignin content was higher and the organic matter content was lower in non-Bt than in Bt maize. Organic matter depletion over time was associated with a decrease in primary consumer abundance and an increase in their trophic niche width in both Bt and non-Bt maize, but it was faster in the former. The abundance of primary consumers and predators was higher in non-Bt than in Bt maize, but the distribution of organisms across trophic levels differed between varieties, with prey availability being lower in non-Bt than in Bt maize. This allowed Bt-associated predators to maintain a diet based primarily on the maize food chain throughout the experimental period. In contrast, non-Bt-associated predators were more dependent on weed-feeding prey by the end of the experiment, increasing the coupling between the maize and weed energy channels in the soil food web. Some taxon-specific effects were evident. Less vagile organisms such as Diptera had a specific diet mostly related to maize regardless of variety and time, while the diets of more vagile organisms like Coleoptera and Opiliones changed the most over time. Overall, our results suggest that the attractiveness of non-Bt maize residues for invertebrate consumers is higher than the Bt variety, although the higher recalcitrant content following decomposition reduces it over time. The attractiveness also affects the movement of invertebrate predators (potentially including pest control agents) and thus nutrient flows in tri-trophic detritus-based food webs in cultivated and uncultivated plots. • Soil food webs based on Bt/non Bt maize and weed residues were explored. • Overall, invertebrate abundance on residues was higher in non-Bt than in Bt maize. • After 5 months of decomposition, residue quality was lower in non-Bt maize. • After 5 months, prey availability for predators was lower in non-Bt than in Bt maize. • Low prey availability increased weed-based prey consumption by non-Bt predators. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
8. Effects of disturbance on an urban river food web.
- Author
-
CALIZZA, EDOARDO, COSTANTINI, MARIA LETIZIA, ROSSI, DAVID, CARLINO, PASQUALE, and ROSSI, LORETO
- Subjects
FOOD chains ,ECOLOGICAL disturbances ,INVERTEBRATES ,DETRITUS ,ISOTOPE dilution analysis - Abstract
1. Natural and anthropogenic disturbances are influential factors in river ecosystems. Lowland rivers that cross urbanised areas experience direct disturbance due to urbanisation, affecting suitability for many vertebrate and invertebrate species and with important implications for ecosystem functioning and stability. In addition, lowland rivers are potentially subjected to major flood events, whose effects may be exacerbated by urbanisation in the river basin. A greater understanding of the combined effects of flood disturbance and urbanisation is needed if we are to preserve riverine ecosystems and improve management strategies. 2. We characterised macroinvertebrate, detritus-based food webs upstream and downstream of Rome (Italy) before a period of exceptional flooding and at intervals until 71 days following the final flood event. We studied community and food-web characteristics, combining carbon and nitrogen stable isotope analysis with macroinvertebrate population census data. 3. The flood altered the species assemblage at both upstream and downstream locations. The food webs shifted towards a more complex configuration, with increased trophic generalism, linkage density and mean chain length. However, the food web at the upstream location gradually recovered its pre-flood configuration, whereas at the downstream location, where flood effects were stronger, the food web showed little capacity for recovery within the time span of the study. The contrasting food-web responses can be explained with reference to differences in resource availability for detritivores and predators and in water turbidity, which in turn reflect an interaction between flood disturbance and river basin urbanisation. 4. The description of short-term variations in food-web properties may help to improve ecosystem monitoring and the management of freshwater bodies and can be used to assess short-term and long-term effects of disturbance. A better understanding of the negative effects of urban pressure on macroinvertebrate community stability should help to define appropriate measures for the conservation and restoration of urbanised river areas, especially given that extreme flood events are expected to increase due to climatic change. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
9. Does stable isotope analysis separate transgenic and traditional corn (Zea mays L.) detritus and their consumers?
- Author
-
Rossi, Loreto, Costantini, Maria Letizia, and Brilli, Mauro
- Subjects
- *
SEDIMENTS , *BIOGEOCHEMICAL cycles , *PLANT shoots , *AGRICULTURE - Abstract
Abstract: Transgenic corn crops (including the Bt variety) are expanding rapidly worldwide, and the large amounts of cultural residues remaining after harvest pose questions about the fate of this novel source of plant detritus in soil. To verify whether transgenic and conventional corn litters were different in their isotopic signatures, the 13C and 15N stable isotopes of different portions of Bt and non-Bt Aristis corn plants after harvest were analysed. Laboratory feeding experiments were then conducted to assess the transfer of corn isotopic signals to detritivores using the isopod Trachelipus sp., reared on either Bt or non-Bt corn dead leaves as the only food source. δ 15N differed significantly between Bt and non-Bt corn in kernels and stems, whereas both δ 15N and δ 13C were different in leaves before and after exposure to isopods. During feeding, the N and C isotopic signatures of isopods shifted towards the diet values. Significant differences existed both between sampling dates and corn treatments. The results suggest that detritus from transgenic and conventional corn crops may have different isotopic signatures and the isotopic differences can persist through the trophic levels, making corn detritus feeders suitable sentinel species for the Bt corn isotopic signal in agroecosystems. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
10. Top-down control of reed detritus processing in a lake littoral zone: experimental evidence of a seasonal compensation between fish and invertebrate predation
- Author
-
Loreto Rossi, Maria Letizia Costantini, Giorgio Mancinelli, Mancinelli, Giorgio, Costantini, Ml, and Rossi, Loreto
- Subjects
Detritus ,leaf detritus processing ,predatory fish ,predatory invertebrates ,seasonality ,trophic cascade ,Ecology ,fungi ,Detritivore ,Aquatic Science ,Biology ,Predation ,Predatory fish ,Exclosure ,Littoral zone ,trophic cascade, predatory fish, predatory invertebrates, leaf detritus processing, seasonality ,Trophic cascade ,Ecology, Evolution, Behavior and Systematics ,Invertebrate - Abstract
We investigated whether predatory fish exert a top-down control on reed leaf packs processing in a lake littoral zone through a trophic cascade. Exclosure experiments were repeated in summer and winter, under high and low natural fish abundance, respectively. Fish exclusion effects on detritus processing and fungal conditioning were consistent with trophic cascade predictions only in summer. In winter, however, results indicated that a trophic cascade was induced by predatory invertebrates. In both seasons, variations in detritivores abundance generally supported a cascade scenario, whereas several taxon-specific departures occurred during the experimental periods. We conclude suggesting that predators may continuously regulate leaf detritus processing in lake littoral zones, through a seasonal shift in the relative contribution of fish and invertebrate predation.
- Published
- 2007
11. The influence of allochthonous leaf detritus on the occurrence of crustacean detritivores in the soft-bottom macrobenthos of the Po River delta area (northwestern Adriatic Sea)
- Author
-
Giorgio Mancinelli, Loreto Rossi, Mancinelli, Giorgio, and Rossi, Loreto
- Subjects
education.field_of_study ,Detritus ,biology ,Ecology ,Cymodocea nodosa ,detritivore crustaceans ,Population ,northwestern adriatic sea ,Detritivore ,leaf detritus ,detritivore crustaceans, leaf detritus, northwestern Adriatic Sea, soft-bottom macrobenthos ,Aquatic Science ,Oceanography ,biology.organism_classification ,Mediterranean sea ,Benthic zone ,Macrobenthos ,soft-bottom macrobenthos ,Zostera ,education - Abstract
Core samples were examined quarterly at two coastal sites (S1 and S2) and at an offshore station (S3) located in the Po River delta area (northwestern Adriatic Sea). Analyses focused on (i) occurrence of coarse detritus of allochthonous origin in the sedimentary matrix and (ii) the relative influence of macrodetritus enrichment and other environmental factors on the vagile macrofauna. Plant debris occurred in site S1 sediments only in summer and autumn; in contrast, fragments of the phanerogams Cymodocea nodosa and Zostera spp. were found in site S2 sediment throughout the sampling period. Sediments from the offshore site S3 were characterized by negligible plant material, even though in summer and autumn samples debris of continental origin was observed. Even though leaf detritus occurrence at site S2 was ∼5-fold higher compared to the other coastal site S1, it did not influence the total organic matter and its distribution among grain-size classes. Conversely, the specific organic content of dimensional fractions provided an effective assessment of detritus enrichment processes occurring at the two coastal sites. A group of brackish-originated crustaceans (i.e. the amphipods Gammarus insensibilis and G. aequicauda and the isopod Idotea baltica ) was the main determinant of among-site multivariate differences in the vagile macrofauna; depositivorous ophiuroids accounted for the residual differences observed during the study period. The analysis of taxa abundance and individual body size indicated that in both site S1 and S3 macrodetritus advection to the benthic system corresponded with passive dispersal of brackish crustaceans, that provided a negligible contribution to the macrobenthic production. In contrast, in site S2 allochthonous inputs from marginal environments could have represented the key factor for the persistence of an authochthonous population of Gammarus insensibilis . The amphipod provided a considerable (19·4%) contribution to the total macrobenthic production of the site, dominated by filter-feeding bivalves and tubicolous deposit feeders. The potential effects of detritivorous crustaceans on soft-bottom macrobenthic assemblages of the northern Adriatic Sea are discussed.
- Published
- 2002
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.