Experimental Analysis of Nest Predation: Effects of Habitat and Nest Distribution

Depredation of artificial avian ground nests was studied in 1994 and 1995 on cool-season and warm-season grasslands in western New York State. The study examined the effects of habitat type and distance from forested edge on nest success in adjacent fields. Two experiments were conducted. The first examined the effects of nest distribution on nest success. Experimental predation rates were highest at the field-forest boundary, although there was no correlation between predation rate and distance from edge. Overall predation rates for cool-season grasslands differed significantly between years, with predation rates being higher during the 1995 field season. The second experiment examined the effects of dense nesting cover on nest success. Predation rates for nests in dense nesting cover varied among distance classes in 1995 but not in 1994; predation rates were also higher in 1995 than in 1994. Experimental rates of nest predation were similar in pasture/cool-season grasslands and warm-season grasslands in both years, suggesting that dense cover did not improve productivity of ground-nesting birds. Indirect evidence suggested that the primary predators along the forest-field boundaries were mammals, with birds and small mammals most frequently depredating nests away from the edge. This study suggests that dense nesting cover does not increase nesting success for small passerines on our study site

Growth and reproduction of <i>Xyrichthys novacula</i> (Pisces: Labridae) in the Mediterranean Sea

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Habitat Relations and Breeding Biology of Grassland Birds in Western New York: Management Implications

In 1994 we began a study of the habitat relations and breeding biology of grassland birds in western New York. Most fields contained fewer than four grassland species, with Bobolink (Dolichonyx oryzivorous) and Savannah Sparrow (Passerculus sandwichensis) being the two most common species. Species of management concern in the Northeast, such as Henslow\u27s Sparrow (Ammodramus henslowii) and Upland Sandpiper (Bartramia longicauda), were absent from the study area. Bird habitat models generated through Principal Components Analysis and stepwise multiple regression indicated that field area, or variables correlated with area, explained most of the variation in overall grassland bird species richness (partial r2 = 0.43) and abundance (partial r2 = 0.60) and in the abundance of Bobolinks and Savannah Sparrows. Grassland birds were generally absent from fields smaller than 5 hectares. Areas with few shrubs and low horizontal heterogeneity supported more grassland bird species than did fields with more shrubs and high horizontal heterogeneity, and fields with shorter, less dense vegetation had more individuals than did fields with taller, dense vegetation. Few grassland birds occurred in fields planted in switchgrass (Panicum virgatum) monocultures. More than 90 percent of all known nesting pairs fledged young by the end of the first week in July. Nest success was generally high; the proportion of nests fledging one or more young was 0.76 for Savannah Sparrows, 0.54 for Bobolinks, and 0.67 for Eastern Meadowlarks (Sturnella magna). Grassland bird populations in this study may benefit from management practices that increase field area, control shrub invasion, and encourage the growth of grasses other than switchgrass. The current low levels of grazing at Iroquois National Wildlife Refuge, with cattle allowed in pastures only after 15 July, do not appear to be harmful to grassland bird populations

Long-term changes in a benthic assemblage associated with artificial reefs

The aim of the study was to evaluate the long-term development of a hard bottom benthic assemblage over a period of 20 years in an area off the mouth of a large river. The artificial reef of Fregene was selected because benthic assemblage data were available for the period 1981-1992. This artificial reef is located in the mid Tyrrhenian Sea, 5 nautical miles north of the two mouths of the Tevere River (Latium, Italy) and 1.5 nautical miles offshore from Fregene (Rome, Italy). The artificial reef was deployed in March 1981 for fisheries enhancement in 10-14 m of water on a sandy-silty seabed. The Tevere River carries suspended materials and a heavy load of organics since it transports Rome's effluent, resulting in the eutrophic state of area waters. Benthic sampling was conducted in 2001 by SCUBA diving; two standard surfaces of 400 cm 2 were scraped from the vertical walls of the same uppermost block in four different periods. All organisms were identified and counted. The methodology used is the same as that adopted in the previous periods, so that the 2001 data could be compared with past collected data. The benthic assemblage was analysed by cluster analysis using the Bray-Curtis index and clustered using the group average clustering algorithm. The SIMPER procedure was used to identify those taxa that characterize each station group identified by cluster analysis. Changes in benthic assemblages and hydrological trends of the Tevere River were investigated using the cumulative sum series method. The 20-year development of the benthic community, starting from the new substratum, is composed of different phases characterised by different benthic assemblages. In particular five different phases were distinguished: 1. Pioneer species recruitment (May 1981-June 1981); 2. Mytilus galloprovincialis (mussel) dominance (August 1981-November 1983); 3. M. galloprovincialis regression (July 1984-October 1985); 4. M. galloprovincialis absence (91-92); 5. Bryozoans bioconstruction dominance (2001). The dynamic succession of the observed benthic assemblages exhibited a good relation with the Tevere River flow. The Tevere River flow, and the subsequent sedimentation process, seems to have strongly influenced the benthic assemblage succession of the Fregene artificial reef

Hydrodynamical Models of Superfluid Turbulence

This review paper puts together some of our results concerning the application of non equilibrium Thermodynamics to superfluid liquid helium. Two of the most important situations of this quantum fluid are rotating superfluid and superfluid turbulence, both characterized by the presence of quantized vortices (vortex lines whose core is about 1 Angstrom and the quantum of circulation is $h/m$, $h$ being the Plank's constant and $m$ the mass of helium atom). In the first part of the work a non-standard model of superfluid helium, which considers heat flux as independent variable, is briefly recalled, and compared with the well known two-fluid model, in absence of vortices, proposed by Tisza and Landau more than half a century ago. The model is generalized taking into account the presence of vortices in different cases of physical interest: rotating superfluids, counterflow superfluid turbulence (a particular situation in which no mass flux but only heat flux is present) and combined situations of counterflow and rotation. Since vortices are not fixed when all the hydrodynamical fields change, an additional scalar quantity, the averaged vortex line density per unit volume $L$, {\it line density} for short, is introduced in the model as a new field variable and an evolution equation is written for it, both in linear and in nonlinear regimes, via Extended Thermodynamics. Finally, to encompass more general situations, the model is further extended considering the flux of vortex line density as an independent new variable. In all these models the propagation of harmonic waves is studied, motivated by the fact that vortex lines density is experimentally detected via the attenuation of second sound. A new kind of waves, vortex density waves, is also dealt with

Feeding habits of European hake (Merluccius merluccius) in the central Mediterranean Sea

European hake (Merluccius merluccius) is an important predator of deeper shelf-upper slope Mediterranean communities. It is a nectobenthic species distributed over a wide depth range (20−1000 m) throughout the Mediterranean Sea and the north east Atlantic region (Fisher et al., 1987). Notwithstanding the ecological and economic importance (Oliver and Massutí, 1995) of hake in the Mediterranean, many aspects of its biology (e.g., recruitment and reproduction), due to multiple spawning (Sarano, 1986) and the current state of exploitation, are poorly understood (Arneri and Morales-Nin, 2000)

Photocatalytic and oxidative synthetic pathways for highly efficient PANI-TIO2 nanocomposites as organic and inorganic pollutant sorbents

Polyaniline (PANI)-materials have recently been proposed for environmental remediation applications thanks to PANI stability and sorption properties. As an alternative to conventional PANI oxidative syntheses, which involve toxic carcinogenic compounds, an eco-friendly procedure was here adopted starting from benign reactants (aniline-dimer and H2O2) and initiated by ultraviolet (UV)-irradiated TiO2. To unlock the full potential of this procedure, we investigated the roles of TiO2 and H2O2 in the nanocomposites synthesis, with the aim of tailoring the properties of the final material to the desired application. The nanocomposites prepared by varying the TiO2:H2O2:aniline-dimer molar ratios were characterized for their thermal, optical, morphological, structural and surface properties. The reaction mechanism was investigated via mass analyses and X-ray photoelectron spectroscopy. The nanocomposites were tested on both methyl orange and hexavalent chromium removal. A fast dye-sorption was achieved also in the presence of interferents and the recovery of the dye was obtained upon eco-friendly conditions. An efficient Cr(VI) abatement was obtained also after consecutive tests and without any regeneration treatment. The fine understanding of the reaction mechanism allowed us to interpret the pollutant-removal performances of the different materials, leading to tailored nanocomposites in terms of maximum sorption and reduction capability upon consecutive tests even in simulated drinking water

Ultrasound-assisted synthesis of WOx-decorated ZnO photocatalysts for NOx abatement

Heterojunctions based on ZnO have numerous applications, such as water splitting, sensing and energy storage [1]. Recently, ZnO/WO3 composites have shown promising results in the sonocatalytic and photocatalytic degradation of aqueous and gas pollutants [2]. Several synthetic approaches have been reported, including chemical vapor deposition, magnetron sputtering, hydrothermal methods and high temperature annealing. Ultrasound-assisted synthesis can provide a scalable and cost-effective strategy to tailor the catalyst structural and morphological properties [3]. In the present work, pristine ZnO and ZnO/WOx composites were synthesized via a sonochemical method, studying the role of the ultrasound amplitude and mode (continuous/pulsed), metal precursor, WOx content and post-synthetic annealing. The resulting materials were extensively characterized, investigating their structural, morphological, optical, and surface properties. Samples were tested towards the photocatalytic removal of NOx under both UV and visible light irradiation in a batch reactor. A good degree of crystallinity is appreciable even before calcination and better morphological features are observed with respect to reference samples prepared without ultrasounds. The morphological properties can be further tuned by changing the metal precursor and adding a post-synthetic annealing step. Photocatalytic activity is promoted with respect to both benchmark samples (Figure 1)

Triply green polyaniline: UV irradiation-induced synthesis of highly porous PANI/TiO2 composite and its application in dye removal

An environmentally benign procedure for the preparation of polyaniline/TiO2 composites is presented. The UV irradiation-induced synthesis leads to materials with good crystallinity and tailored morphology, showing promising sorption and recycle properties in dye removal tests. A reaction mechanism is proposed on the basis of LC-MS and FT-IR investigations