The Vegetation Resilience After Fire (VRAF) index: Development,implementation and an illustration from central Italy

A suitable index is proposed to evaluate the natural short–medium-term recovery capability of vegetation in burnt areas. The study area covers 2450 km² in western Tuscany (Province of Pisa, Italy). This region is characterized by a typical Mediterranean climate and is subject to fire damage during the dry summer season. Damage is mitigated where a natural rapid regrowth of vegetation prevents soil erosion, supporting the return to a natural pre-fire state.     

Bulk transfer velocity to and from natural and artificial surfaces

A wide set of published mass and heat transfer data is reviewed in terms of the stochastic renewal theory. A simple model is then proposed describing the transfer in terms of the fluid bulk properties. Two expressions are presented and they enable us to evaluate the bulk transfer velocity as a function of the turbulence of the flow for smooth and fully-rough surfaces in large ranges of Schmidt (or Prandtl) and Reynolds numbers. The transfer over transitional surfaces can also be evaluated by using a simple criterion for the choice of the right expression. The proposed relationships agree satisfactorily with data from laboratory and atmospheric measurements, for both solid and liquid surfaces.     

Vertical profiles of biological particle concentrations under convective conditions

Measurements of vertical profiles of pollen concentration from local and remote sources have been made during convective conditions with balloon-mounted rotating impaction samplers.The vertical profiles of local particles appear to be usually characterized by a decrease in the ground layer and by almost constant values aloft. A minimum often occurs at levels between 100 and 200 m.The concentration profiles of pollen from remote sources present a peak at heights of some hundred meters.By comparing the observed profiles with some published models of transport, it appears that: (i) because of differing eddy scales, turbulent transport affects the settling of pollen differently close to the ground than aloft; and (ii) turbulent anisotropies related to the dynamic and thermal structure of the atmosphere may affect the vertical distribution of particulate matter in the boundary layer.     

Enhancing the credibility of ecology: Interacting along and across hierarchical scales

A wide range of space and time scales characterize the processes and phenomena which interact to shape environmental condition and trends. Important perspectives of environmental space and time include the role of terrestrial and astronomical factors in shaping climatic change, insights to be gained from the pre-historical record, relations between disturbance and biotic responses, episodic extreme events and large-scale phenomena, cumulative impacts, fast — slow processes and memory reservoirs. Scales in physical, chemical and biological phenomena have parallels in human driving forces, societal relations and decision — making processes, and environmental scales of space and time thus have perceptual as well as physical (objective) dimensions. Scale is clearly more than just size and dimension, and there is a growing body of examples on how zooming along and across hierarchical scales can help in seeking explanation (how) and significance (why), and in revealing emergent properties. Scaling can also act as a motor for new approaches to scientific cooperation. Such evolving scales in scientific cooperation are examined in relation to three international research programmes (IBP, MAB, IGBP), to various sub-disciplines of ecology and biogeography, and to the restructuring of a largish research institute in Montpellier (France). An overall conclusion is that scaling issues may provide a stimulus to increased coherence within the science of ecology itself, and may facilitate mutually supportive links with other scientific domains and society at large.The views expressed are those of the authors and not necessarily those of the authors' employers.     

Suspended sediment transport analysis in two Italian instrumented catchments

Suspended sediment transport in streams is an effective indicator of soil erosion at the watershed scale. This process was studied using the data obtained from two continuous monitoring stations installed in Italian watersheds, the Rio Cordon and Torrente Carapelle. The catchments have substantially different climatic, morphological and land use characteristics. The Rio Cordon, a small Alpine watershed, has been monitored since 1986, while in the Torrente Carapelle, a medium-size Mediterranean watershed, the monitoring station has provided data since 2007. Several flood events with suspended sediment transport were isolated in the two catchments, excluding those determined by snowmelt in the Rio Cordon as this process does not affect the Carapelle watershed. Analysis of the events showed different behavior in terms of hysteresis loop trends between water discharge (m³ s^-1) and suspended sediment concentration (g l^-1) values, as the Rio Cordon confirms clockwise relationships most frequently, while counter-clockwise trends represent the majority of cases for the Carapelle Torrent. The different behavior of the two watersheds was further analyzed by evaluating relationships between the main hydrological parameters related to suspended sediment transport. Runoff controls the total sediment budget in both catchments. In contrast, it was noted that the runoff process does not interfere in the magnitude of the suspended sediment transport in the Rio Cordon catchment, while variations due to the larger size of the catchment area characterize the events in the Carapelle watershed. Lastly, a flow peak threshold that determines the advance or delay of the hydrograph peak with respect to the sedigraph peak was established for the Carapelle Torrent, while it was not reported in the Rio Cordon.     

Food preferences and rhythms of feeding activity of two co‐existing demersal fish,the longspine snipefish,Macroramphosus scolopax (Linnaeus, 1758), and the boarfish Capros aper (Linnaeus, 1758), on the Mediterranean deep shelf

The feeding behaviour of two potentially competing species, the longspine snipefish, Macroramphosus scolopax, and the boarfish Capros aper was examined. While both species are very abundant along the Mediterranean coast and are regularly caught by demersal trawlers, they are of no commercial value. The diets of boarfish and longspine snipefish were investigated from samples collected between January 2001 and May 2002. Variations in the diet with fish size and season, as well as diet overlap and diversity were explored. Mysid shrimps, amphipods and gastropods were the most important food items in the diet of longspine snipefish. During ontogenetic development, M. scolopax occupies different trophic levels: the diet shifts from being predominantly composed of mysids (Anchialina agilis, Lophogaster typicus, Erythrops sp., Leptomysis spp.) in the smaller longspine snipefish [<6.5 cm total length (TL)] towards decapods (Anapagurus laevis) and amphipods (Leucothoe incisa, Eusirus longipes, Hyperidea) in the larger individuals (>6.5 cm TL). Crustacean decapods and copepods were the most important prey in the stomachs of boarfish. Mysids (Lo. typicus), euphausiids and nematodes were present in the larger individuals (>8 cm TL). A more generalist diet, still containing copepods, crustacean decapods, gastropods (Limacina retroversa) and a large variety of amphipods (e.g. Phtysica marina, Stenotoe bosphorana) and mysids (e.g. A. agilis, Leptomysis spp., Erythrops sp.), dominated the diet of C. aper between 2 and 8 cm TL. Diet overlap between longspine snipefish and boarfish was very low and the differences in stomach species diversity were explained by season and fish size.     

Interaction Between Waves and Turbulence Within the Nocturnal Boundary Layer

Boundary-Layer Meteorology - Within the roughness sublayer (RSL) of dense urban canopies composed of uniformly distributed cuboids, the time and planar-averaged mean velocity profile exhibits an...     

Late Quaternary palaeohydrology of Lake Pergusa (Sicily,southern Italy) as inferred by stable isotopes of lacustrine carbonates

Ten meters of lacustrine deposits retrieved from Lake Pergusa (Sicily, southern Italy) were investigated through stable isotope composition (carbon and oxygen) of authigenic carbonate (calcareous muds) and freshwater shells. The core chronology was established through three AMS dates, and by correlation with a previously dated nearby core. Stable isotope data show that the lake water evolution was mainly dominated by evaporation. Between ca. 20 and 28 ka the recovered sediments have very high δ¹⁸O values, likely corresponding to very dry climatic conditions. The observed rapid oscillations in the δ¹⁸O of the recovered sediments during this period also suggest important climatic fluctuations. More humid conditions dominated during the Holocene period, with the wettest interval occurring between ca. 9000 and 3000 years BP. Late Holocene sediments represent a substantial return to drier conditions. The available pollen data from a nearby core substantially confirm this general climatic trend during the Holocene. The positive correlation between δ¹³C of the calcareous muds and carbonate content suggests that biological activity played a key role in the carbon isotope evolution of dissolved inorganic carbon. However, a clear climatic signal is not evident from the δ¹³C record.