Franceschi M.,MUSE |
Massironi M.,University of Padua |
Franceschi P.,Data Management |
Picotti V.,University of Bologna
Rendiconti Online Societa Geologica Italiana | Year: 2013
The Calcari Grigi carbonate platform (Southern Alps, Italy) (size ∼100km × 100km, up to 400m thick) consists of several sub-environments (tidal flats, deep lagoons, oolitic shoals), now exhumed in the Southern Alps (Italy), a poorly deformed portion of the Mesozoic passive margin of Adria. Despite some alpine faulting and folding, lateral relationships between Jurassic units are still preserved. During Early Jurassic, the platform was affected by synsedimentary tectonics, testified by exposed structures, controlling sharp variations in the thickness of its units. Excellent outcrop continuity, extensive geological mapping and previous studies provide a great wealth of field data that give the opportunity to produce a 3D model of a seismic-scale carbonate platform. 3D modeling was carried out with SKUA®. Main stratigraphic horizons and geometries of the sedimentary prisms were modeled. Spatial variability of the platform units' thickness was studied with geostatistics to retrieve information about the arrangement of the Jurassic fault system that drove subsidence during the platform growth. This helped to estimate the position of main Jurassic faults and revealed an extensive orthorhombic fault-network at the platform scale. The 3D model can now be populated with facies information, derived from outcrop data and geologic maps, to evaluate the influence of tectonics on the depositional environments. The model of a carbonate platform of this size potentially represents a useful analogue for carbonate reservoirs and help the understanding of similar buried sedimentary body. © Società Geologica Italiana, Roma 2013.
Marchetti L.,University of Padua |
Avanzini M.,MUSE |
Conti M.A.,University of Rome La Sapienza
Ichnos:an International Journal of Plant and Animal | Year: 2013
Studies on Early Permian tetrapod ichnofauna emphasized the scarcity of forms from Italian sites. A revision work on the entire collections revealed the presence of Hyloidichnus bifurcatus Gilmore, 1927 and Limnopus heterodactylus (King, 1845). The ichnoassociation now lists seven ichnogenera: Amphisauropus, Batrachichnus, Dromopus, Erpetopus, Hyloidichnus, Limnopus, Varanopus. These new data enlarge the ichnoceonosis, adding tracks of medium-size captorhinomorphs (Hyloidichnus) and temnospondyls (Limnopus) to the Italian ichnofauna, previously characterized by scarcity of predators and amphibians. Radiometric ages give a strong age constraint to the ichnoassociation (Early Kungurian), allowing useful correlations to contemporary successions all over the world. The main difference is the absence of Ichniotherium and Dimetropus, and this could have a stratigraphic or paleoenvironmental significance. The fauna is similar in two main basins, Collio and Orobic. It differs solely in the proportions between ichnotaxa, with a predominance of areoscelid traces (Dromopus) in the Collio Basin and of captorhinomorph traces (Erpetopus, Varanopus, Hyloidichnus) in the Orobic Basin. This datum could reflect slightly different environments, seasonal in the Collio Basin (alluvial plain) and more arid in the Orobic Basin (playa-like). The lack of some forms in smaller basins of the Athesian Volcanic Complex is probably due to a bias. © 2013 Copyright Taylor and Francis Group, LLC.
Abeli T.,University of Pavia |
Zubani L.,Flora Conservation s.r.l. Pavia |
Bonomi C.,MUSE |
Parolo G.,MUSE |
Gargano D.,University of Calabria
Plant Species Biology | Year: 2015
Fluctuating asymmetry (FA), the deviation from the normal symmetrical condition of a morphological trait having specific morphological symmetry, increases in response to environmental and genetic stress, is related to phenotypic plasticity and is considered a tool for monitoring a species conservation status. However, FA-stress relations are dependent on measured traits or species-specific characteristics such as mating system and habitat. This study investigates the relationships between FA, genetic diversity, population size, density and individual fitness traits (plant height, fruit and seed set), in the endemic Aquilegia thalictrifolia, a mixed breeder that is declining, but maintaining high levels of heterozygosity. Leaf and flower FA and other traits were investigated in 10 populations of A. thalictrifolia, the whole species range. As a result, we found similar patterns of FA in leaves and flowers between populations, indicating a homogenous level of stress between populations that differed for other traits. FA and the other traits were not related, including heterozygosity. Heterozygosity was not related to individual fitness traits with the exception of plant height. In accordance with other studies, we found that the role of FA as a tool for assessing the conservation status of a species or population should be reconsidered. However, we conclude that a low level of FA should not automatically be considered an indicator of good conservation status or low level of stress, because in species that evolved in highly stable environments it may indicate a scarce ability to plastically respond to environmental changes, as a consequence of environmental and genetic canalization. Further investigation of this point is needed. © 2015 The Society for the Study of Species Biology.
Casarotto C.,MUSE |
Bertoni E.,MUSE |
Trenti A.,Autonomous Province of Trento
Rendiconti Online Societa Geologica Italiana | Year: 2015
In occasion of the preparation of a new inventory for Trentino glaciers (2013), all historically available data (1958 CGI, 1987 SAT, 2003 PAT) were digitized in a geographic information system (GIS) with the aim to reconstruct the evolution of the glaciers from the end of the Little Ice Age (LIA) up to date. Through limits of moraines and glacial sediments, as well as those of active rock glaciers, the polygons of the glaciers at the maximum of the LIA (around 1850) were defined in GIS. At that time glaciers filled an area of about 110 km2. In the early 1900s, however, some glaciers disappeared, for example on Monzoni during the World War I. The inventory 2013 (PAT) counts 120 glaciers with total area of about 32 km2. The average annual losses of glacial surface (ÄSy, in [%]) were compared for each of the considered four time periods. We have noticed that these losses have grown exponentially. With the three-dimensional analysis of the 2003 and 2013 inventories, the average annual reduction in thickness was determined for the glaciers representative of the main mountain groups, for example on Adamello Glacier, and it has been observed to achieve values up to 4 000 mm water equivalent. These data, which have a strong seasonal connotation, are comparable to those of monsoon systems, almost as if they would like to witness the tropicalization of climate resulting in global warming.
Abeli T.,University of Pavia |
Gentili R.,University of Milan Bicocca |
Mondoni A.,MUSE |
Orsenigo S.,University of Pavia |
Rossi G.,University of Pavia
Journal of Biogeography | Year: 2014
Aim: Populations at the edge of a species' distribution range may differ substantially from central populations. Peripheral populations may have either a high evolutionary potential or be prone to extinction, but the processes driving these outcomes are still unclear. Peripheral plant populations have been the subject of numerous studies and reviews, with many focusing on their genetic characteristics. In this review, we consider the effect of marginality on demographic species-specific traits. Location: World-wide. Methods: We reviewed the literature based on direct comparisons between central and peripheral plant populations. Strict inclusion criteria were applied to avoid biased analysis that may arise as a result of inaccurate boundary considerations or inappropriate comparisons. We inferred from the published data whether a certain trait had a better performance in central or peripheral populations (reliability of the abundant centre hypothesis, ACH). Results: There have not been enough studies on plant performance to allow for generalizations on the effects of marginality on plants. ACH expectations were not met in most cases and specific responses to marginality were observed at the species and population levels. Population and plant size more often met the ACH assumptions, suggesting that most geographically peripheral populations are also ecologically marginal. The availability of resources, the reproductive strategy, the level of ploidy and the ability to cope with interspecific competitors seem to drive the numerous exceptions to the ACH expectations. Main conclusions: The large numbers of exceptions to the ACH expectations suggest that a new comprehensive theory is needed to explain the effects of marginality in plants and to identify any general patterns. From the theoretical point of view, we propose that population history and dynamics should be considered when attempting to explain the processes that occur in peripheral plant populations. © 2013 John Wiley & Sons Ltd.