1,721,014 research outputs found
Microdistribution of macroinvertebrates in a temporary pond of Central Italy: Taxonomic and functional analyses
Full text linkSpatial distribution of physical and chemical variables and macroinvertebrate composition, structure and functional aspects were investigated in five microhabitats available (Ranunculus acquatilis+ Ranunculus sardous, Spirogyra sp., Juncus effusus, and unvegetated littoral sediments and central sediments) in a temporary pond near Rome during spring 2004. The central sediments were found to differ greatly from the other substrates. They were characterized by higher nutrient contents (total P, total N), organic matter and organic C, and silt and clay in the sediments, and lower dissolved oxygen content and lower pH in the water. Species richness and densities of total macrofauna showed the lowest values in central sediments and the highest ones in submerged macrophytes (Ranunculus spp.) and emergent vegetation (Juncus effusus). Oligochaeta Tubificidae, some Nematoda (Dorylaimus spp.), and Chironomidae Tanypodinae (Procladius sp. and Psectrotanypus varius) and Chironominae (Chironomus plumosus group) characterized the central sediments, whereas Ephemeroptera and most of the Odonata and Coleoptera species were commonly found in submerged macrophyte beds. Some species of Coleoptera and Hemiptera (Hygrobia hermanni, Helochares lividus, Berosus signaticollis and Gerris maculatus) were mainly found in the algal substratum, and some Nematoda species (Tobrilus spp. and Aporcelaimellus obtusicaudatus), Oligochaeta Enchytraeidae, young larvae of Sympetrum and Diptera Ceratopogonidae in littoral sediments. Juncus effusus appeared to be mainly colonized by Chironomidae Orthocladiinae (Psectrocladius sordidellus group and Cotynoneura scutellata) and Tanytarsini (Paratanytarsus sp.). Central sediments also favoured high abundances of collector-gatherers, burrowers and drought resistant forms with passive dispersal, whereas Ranunculus spp. hosted mainly scrapers, shredders, swimmers+divers and active dispersal forms without any resistant stages to desiccation. Juncus plants were mostly colonized by collector-filterers and by organisms capable of both active dispersal and surviving desiccation. Littoral sediments and algae showed similar functional organization and intermediate features between central sediments and submerged macrophyte beds. All these results demonstrate that microhabitat characteristics play a crucial role in selecting macroinvertebrate taxa according to their environmental requirement, feeding mechanism, movement and resistance to drought. Moreover, our study confirms the role of submerged and emergent vegetation in maintaining high biodiversity and suggests that all microhabitats should be considered to provide both an exhaustive collection of species for pond management and conservation and basic insights into the functioning of pond communities. (C) 2009 Elsevier GmbH. All rights reserved
Geochimica e pedogenesi di un profilo costituito da due suoli sovrapposti su una piroclastite vulsina presso ponte san Pietro (Viterbo, Lazio settentrionale)
No full textEcophysiological studies in permanent areas of decidous mixed woods with Quercus cerris L. prevalent in the Alta Valtiberina (Arezzo-Italy).
No full textEdaphic characteristics of Quercus suber woods in Latium.
No full textIn this paper the results are reported of a soil survey done in selected sites of Latium under the most significant Quercus suber woods (Cytiso-Quercetum suberis Testi, Pignatti and Lucattini 1994) previously studied from a phytosociological point of view. After describing the dominant soil type of each area, physical-chemical characteristics have been analysed in order to point out the significance of edaphic factors in the distribution and floristic composition of the Quercus suber coenoses. Bioclimatic, structural and edaphic features of this vegetation showed a great convergence; among all the parameters examined, AWC resulted to be the most effective one in conditioning the mesophilous character of Quercus suber coenoses growing in Latium. In this respect this type of vegetation shows rather strong affinities with mixed Quercus cerris woods, both in the floristic composition and in the edaphic requirements, as already suggested in the most recent phytosociological studies
Edaphic Characters of Brachypodium Communities on the Alps and the Apennines
No full textGrassland communities with Brachypodium cespitosum, B. genuense, or B. rupestre, distributed along Alps and Apennines were analysed, considering soil edaphic measures. Submitted to both principal components and cluster analysis six groups of relevés resulted, whose edaphic structure was compared to nominal characters. As a confirmation of results, stepwise discriminant analysis showed the edaphic characters responsible of the different species presence in the grasslands. As results, Brachypodium rupestre seems to be present on more basic soils, rich of clay, whereas B. genuense grows on more acid soils, rich in nourishment, and B. cespitosum seems to be in an intermediate position. The type of growth then, seems to depend strongly on the edaphic soil conditions.Des pâturages à Brachypodium cespitosum, B. rupestre ou B. genuense, répartis dans les Alpes et les Apennins, ont été étudiés du point de vue des caractères édaphiques. Une analyse en composantes principales suivie d’une classification a permis de déterminer six groupes de relevés dont la composition a été mise en rapport avec les mesures édaphiques. Une analyse discriminante pas à pas a montré les caractères édaphiques les plus corrélés avec la croissance des différentes espèces de Brachypodium de ces pâturages. En résumé, Brachypodium rupestre semble s’installer sur des sols plus basiques et plus riches en argile, tandis que B. genuense croît sur des sols plus acides et plus riches en éléments nutritifs, B. cespitosum se situant dans une position intermédiaire. Il semble donc que le type de croissance dépende fortement des conditions édaphiques.Camiz Sergio, Dowgiallo Giuseppina, Lucchese Fernando. Edaphic characters of Brachypodium communities on the Alps and the Apennines. In: Ecologia mediterranea, tome 17,1991. pp. 33-49
Supplemental_Material_for_A_Whole_Cell_Screen_for_Adjunctive_and_Direct_Antimicrobials_Active_Against_Carbapenem-Resistant_Enterobacteriaceae_by_Smith_et_al – Supplemental material for A Whole-Cell Screen for Adjunctive and Direct Antimicrobials Active against Carbapenem-Resistant Enterobacteriaceae
No full textSupplemental material, Supplemental_Material_for_A_Whole_Cell_Screen_for_Adjunctive_and_Direct_Antimicrobials_Active_Against_Carbapenem-Resistant_Enterobacteriaceae_by_Smith_et_al for A Whole-Cell Screen for Adjunctive and Direct Antimicrobials Active against Carbapenem-Resistant Enterobacteriaceae by Kenneth P. Smith, Matthew G. Dowgiallo, Lucius Chiaraviglio, Prakash Parvatkar, Chungsik Kim, Roman Manetsch and James E. Kirby in SLAS Discovery</p
Chemical soil properties of the nesting sites of two syntopic harvester ants: Messor wasmanni,M.minor.
No full textAssessing the habitat conservation status by soil parameters and plant ecoindicators
Full text linkThe aim of this study was to assess the conservation status of a Natural Reserve located in central Italy through an integrated analysis including soil, lithotype and edaphic parameters, landforms, and plant species. The relationships between soil and vegetation was investigated using soil variables and plant ecoindicators, expressed by: ( i) the Ellenberg's bioindication model; and ( ii) the Hemeroby Index. Vegetation and soil data have been collected in thirty vegetation and soil profiles. Cluster analysis, performed on a matrix 12 variables / 30 releves allowed the detection of two main clusters, each divided into sub-clusters, characterized by peculiar floristic composition and soil characteristics. Clusters were markedly discriminated by soil Available Water Capacity ( AWC). Canonical Correspondence Analysis ( CCA) performed on variables and species matrices allowed to separate two main habitats: ( i) a core habitat represented by patches of temperate forest correlated to soil cycles of water and nutrients; ( ii) an ecotonal habitat composed by mixed evergreen and thermophilous deciduous oak forest, mainly related to the light, temperature and human disturbance regimes
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