Effects of enhanced loads of nutrients on epiphytes on leaves and rhizomes of Posidonia oceanica     

David Balata  Luigi Piazzi  Ugo Nesti  Fabio Bulleri  Iacopo Bertocci 《Journal of Sea Research》2010,63(3-4):173-179

The increase of anthropogenic activities has severely altered both terrestrial and aquatic systems. Urbanisation, excessive use of agricultural fertilisers, organic runoff and climate change have caused an increase of nutrients in coastal waters, altering the diversity and food-web structure of benthic assemblages. The aims of the present paper were to text if an experimentally increased availability of nutrients, primarily nitrogen and phosphorous, in an oligotrophic basin, would affect epiphytic assemblages on leaves and rhizomes of P. oceanica and whether this could change rates of consumption of the plant by herbivores. In particular, we tested the hypothesis i) that changes to species composition and abundance of epiphytic assemblages generated by nutrients enrichment would vary between leaves and rhizomes and that ii) alterations to epiphytic assemblages on leaves might, in turn, modify feeding rates of herbivorous fish. After two years, the structure of both leaf and rhizome epiphytic assemblages responded to changes in nutrient concentrations before the occurrence of drastic alterations to the host plant, but only the former showed significant changes in terms of species composition. Moreover, a larger intensity of grazing on P. oceanica leaves was documented in experimentally enriched areas than in controls. The present findings and conclusions are applicable to other systems where patterns of biodiversity depend on changes in the availability of nutrients due to natural or anthropogenic events, likely interacting with biological processes, such as competition and grazing.  相似文献   

Capacity and economic efficiency in small-scale fisheries: Evidence from the Mediterranean Sea   总被引：4，自引：0，他引：4  

Lorenzo Idda  Fabio A. Madau  Pietro Pulina   《Marine Policy》2009,33(5):860-867

To design an effective capacity management plan for small-scale fisheries one must understand what one is measuring and define its capacity. As recognized by some authors, overcapacity is a problem that generally affects small-scale fisheries just as much as it does other types of fishing. This study aims to estimate fishing capacity, technical efficiency, scale efficiency and capacity utilization in a particular small-scale fishery in the Mediterranean, i.e., the Northwest Sardinian fleet in Italy. A non-parametric approach using a data envelopment analysis (DEA) model was applied to a sample of trawls in order to estimate their economic capacity, and related measurements were taken. The capacity and efficiency with reference to two different alternative scenarios were also calculated.  相似文献   

Hard coastal-defence structures as habitats for native and exotic rocky-bottom species   总被引：1，自引：0，他引：1  

Vaselli S  Bulleri F  Benedetti-Cecchi L 《Marine environmental research》2008,66(4):395-403

The use of hard coastal-defence structures, like breakwaters and seawalls, is rapidly increasing to prevent coastal erosion. We compared low-shore assemblages between wave-protected and wave-exposed habitats on breakwaters along a sandy shore of Tuscany (North-Western Mediterranean). Assemblages were generally characterized by a low diversity of taxa, with space monopolized by Mytilus galloprovincialis and Corallina elongata on the seaward side of breakwaters and by filamentous algae on the landward side. Assemblages in wave-protected habitats were characterized by greater temporal stability than those in exposed habitats and supported non-indigenous macroalgae such as Caulerpa racemosa and Codium fragile ssp. tomentosoides. Hence, the introduction of hard coastal-defence structures in otherwise soft-bottom dominated areas, attracting native and exotic rocky-bottom species, should be of great concern for the conservation of marine biodiversity at local and regional scales and for the management of biological invasions.  相似文献   

Unpacking some of the linkages between uncertainties in observational data and the simulation of different hydrological processes using the Pitman model in the data scarce Zambezi River basin     

Denis A. Hughes  Fabio Farinosi 《水文研究》2021,35(4):e14141

The main objective of this study was to use an uncertainty version of a widely used monthly time step, semi-distributed model (the Pitman model) to explore the equifinalities in the way in which the main hydrological processes are simulated and any identifiable linkages with uncertainties in the available observational data. The study area is the Zambezi River basin and 17 gauged sub-basins have been included in the analyses. Unfortunately, it is not generally possible to quantify some of the observational uncertainties in such a data scarce area and mostly we are limited to identifying where these data are clearly deficient (i.e., erroneous or non-representative). The overall conclusion is that the equifinalities in the model are hugely dominant in terms of the uncertainties in the relative occurrence of different runoff generating processes, although water use uncertainties in the semi-arid parts of the basin can contribute to these uncertainties. The identification of landscape features that suggest the occurrence of saturation excess surface runoff provides some information to constrain the model. Improved independent estimates of groundwater recharge is also identified as a key source of observational data that would help a great deal in constraining the model parameter space and therefore reducing some of the model equifinality.  相似文献   

The Imaclim-R model: infrastructures, technical inertia and the costs of low carbon futures under imperfect foresight   总被引：2，自引：2，他引：0  

Henri Waisman  Céline Guivarch  Fabio Grazi  Jean Charles Hourcade 《Climatic change》2012,114(1):101-120

This paper analyzes the transition costs of moving towards a low carbon society when the second-best nature of the economy is accounted for. We emphasize the consequences on mitigation costs of considering the interplay between a) technical systems inertia, including slow infrastructure turnover in transportation and construction; and b) imperfect foresight influencing investment decisions. To this end, the hybrid general equilibrium modeling framework Imaclim-R is employed as it allows for transitory partial adjustments of the economy and captures their impact on the dynamics of economic growth. The modeling exercise quantitatively emphasizes the a) specific risks that the interplay between inertia and imperfect foresight leads to high macroeconomic costs of carbon abatement measures; b) opportunities of co-benefits from climate policies permitted by the correction of sub-optimalities in the reference scenarios. The article draws insights for the framing of future climate architectures by studying the role of measures that act complementarily to carbon pricing in the transport sector. In particular, reallocating public investment towards low-carbon transport infrastructure significantly reduces the overall macroeconomic costs of a given GHG stabilization target and even creates the room for long-term net economic benefits from climate policies.  相似文献   

Assessment of the impact of climate change on the olive flowering in Calabria (southern Italy)   总被引：1，自引：1，他引：0  

Elenio Avolio  Fabio Orlandi  Carlo Bellecci  Marco Fornaciari  Stefano Federico 《Theoretical and Applied Climatology》2012,107(3-4):531-540

In phenological studies, plant development and its relationship with meteorological conditions are considered in order to investigate the influence of climatic changes on the characteristics of many crop species. In this work, the impact of climate change on the flowering of the olive tree (Olea europaea L.) in Calabria, southern Italy, has been studied. Olive is one of the most important plant species in the Mediterranean area and, at the same time, Calabria is one of the most representative regions of this area, both geographically and climatically. The work is divided into two main research activities. First, the behaviour of olive tree in Calabria and the influence of temperature on phenological phases of this crop are investigated. An aerobiological method is used to determine the olive flowering dates through the analysis of pollen data collected in three experimental fields for an 11-year study period (1999–2009). Second, the study of climate change in Calabria at high spatial and temporal resolution is performed. A dynamical downscaling procedure is applied for the regionalization of large-scale climate analysis derived from general circulation models for two representative climatic periods (1981–2000 and 2081–2100); the A2 IPCC scenario is used for future climate projections. The final part of this work is the integration of the results of the two research activities to predict the olive flowering variation for the future climatic conditions. In agreement with our previous works, we found a significant correlation between the phenological phases and temperature. For the twenty-first century, an advance of pollen season in Calabria of about 9?days, on average, is expected for each degree of temperature rise. From phenological model results, on the basis of future climate predictions over Calabria, an anticipation of maximum olive flowering between 10 and 34?days is expected, depending on the area. The results of this work are useful for adaptation and mitigation strategies, and for making concrete assessments about biological and environmental changes.  相似文献   

Evaluating and improving semi-analytic modelling of dust in galaxies based on radiative transfer calculations     

Fabio Fontanot  Rachel S. Somerville  Laura Silva  Pierluigi Monaco  Ramin Skibba 《Monthly notices of the Royal Astronomical Society》2009,392(2):553-569

  相似文献   

Late Holocene vertical deformation along the coast of Pantelleria Island (Sicily Channel, Italy)     

Giorgio de Guidi  Carmelo Monaco   《Quaternary International》2009,206(1-2):158

According to historical reports, the north-eastern coastal sector of the volcanic Pantelleria Island (Sicily Channel, Italy) was uplifted up to 1.0 m a.s.l. in the year preceding the October 1891 offshore eruptive event. To better understand the nature and timing of coastal uplift, a detailed survey of morphological and biological indicators of raised palaeo-shorelines has been carried out along the island coastline. This survey identified raised palaeo-shoreline levels at three elevation ranges: 2.5–4.2 m a.s.l. (highest), 1.5–2.7 m a.s.l. (intermediate) and 0.4–1.0 m a.s.l. (lowest). Radiocarbon dating on samples of corals and vermetids placed tight temporal constraints on the uplifting of the raised shorelines. In general, they indicate that the north-eastern sector of the island, centred on the area of Cala del Gadir, has undergone major uplifting, tilting the island towards the southwest from 900 years ago. Applying accurate corrections for sea-level variations, the total amount of volcano-tectonic uplift can be estimated. Uplift rates up to 5 mm/a suggest that the vertical deformation was caused by inflation processes related to magmatic intrusion along feeding fissures.  相似文献   

Application of biotic indices and relationship with structural and functional features of macrobenthic community in the lagoon of Venice: an example over a long time series of data     

Pranovi F  Da Ponte F  Torricelli P 《Marine pollution bulletin》2007,54(10):1607-1618

In the context of the application of WFD, a scientific debate is growing about the applicability of biotic indices in coastal and transitional waters. In the present work, the question about the discriminating power of different biotic indices and the relationships with the structure and functioning of the macrobenthic community in a transitional environment is discussed. A time series of samples collected during the last 70 years in the lagoon of Venice, reflecting different environmental conditions (a sort of 'pristine state' in 1935, the distrophic crisis in 1988 and subsequent modifications in 1990, the invasion by an alien species and the developing of high impacting fishery in 1999) has been used. The comparison of results obtained by applying different biotic indices, such as AMBI, Bentix and BOPA, shows differences in the discriminating power of indices and a general overestimation of environmental conditions. Discrepancies between environmental status as indicated by biotic indices and the structure and functioning of the benthic community have been highlighted.  相似文献   

Evidence of a shallow magma intrusion beneath the NE Rift system of Mt. Etna during 2013          下载免费PDF全文

Valentina Bruno  Carmelo Ferlito  Mario Mattia  Carmelo Monaco  Massimo Rossi  Danila Scandura 《地学学报》2016,28(5):356-363

Continuous GPS (CGPS) data, collected at Mt. Etna between April 2012 and October 2013, clearly define inflation/deflation processes typically observed before/after an eruption onset. During the inflationary process from May to October 2013, a particular deformation pattern localised in the upper North Eastern sector of the volcano suggests that a magma intrusion had occurred a few km away from the axis of the summit craters, beneath the NE Rift system. This is the first time that this pattern has been recorded by CGPS data at Mt. Etna. We believe that this inflation process might have taken place periodically at Mt. Etna and might be associated with the intrusion of batches of magma that are separate from the main feeding system. We provide a model to explain this unusual behaviour and the eruptive regime of this rift zone, which is characterised by long periods of quiescence followed by often dangerous eruptions in which vents can open at low elevation and thus threaten the villages in this sector of the volcano.  相似文献