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171.
Guido Chelazzi Stefano Focardi Jean Louis Deneubourg Riccardo Innocenti 《Behavioral ecology and sociobiology》1983,14(1):15-20
Summary Computerized screening of all the positions recorded during a synodic month on 120 individually marked chitons (Acanthopleura gemmata) pinpointed their preferential resting points. Unlike the majority of intertidal chitons so far studied, A. gemmata rests in well-defined homes actively dug in the rock. Homes proved to be not strictly individual and periodically interchangeable. A complex aggressive behaviour was recorded in the field when two animals came in contact at home. When competing for ownership of a resting site rival chitons may suppress their nocturnal feeding activity. Despite its strong home-related territoriality A. gemmata showed no mutual exclusion on the feeding area. The highly specialized resting habits clearly protects A. gemmata from its most important predator, the toad fish Arothron immaculatus. The behaviour of A. gemmata is compared to that of other chitons and gastropods, and the current hypotheses concerning the adaptive value of the homing behaviour in littoral molluscs are discussed. 相似文献
172.
Stefano Loppi Fabrizio Chiti Adelmo Corsini Luca Bernardi 《Environmental monitoring and assessment》1994,29(1):17-27
The epiphytic lichen Parmelia caperata (L.) Ach. was used as bioaccumulator of the heavy metals Cd, Cr, Cu, Hg, Ni, Pb and Zn in the environs of the town of Pistoia (central northern Italy). The concentrations of Cd, Cr, Ni, Hg and Pb were comparable with those found in areas not subject to atmospheric pollution. Copper and especially Zn were found in rather high concentrations. Fertilizers and pesticides were the main source of atmospheric contamination. 相似文献
173.
Giovanni Di Matteo Pierfrancesco Nardi Stefano Grego Caterina Guidi 《The Environmentalist》2018,38(4):508-516
The first step in planning the actions for climate change adaptation involves performing Climate Change Vulnerability Assessment (CCVA) to vulnerable populations and ecological systems. The study aims to perform a bibliometric analysis on the CCVA research field to identify how it was structured in terms of the mostly occurring research terms and their citation impact. A set of scientific papers related to CCVA (n?=?8941) were retrieved via Elsevier’s Scopus database over the period 1996–2016 using specific keywords. The search was carried out in February 2017. The number of yearly papers published in CCVA research field increased after 2006, increasing more than six times in 2016. Our co-occurrences term analysis grouped four clusters related to (i) exposure, sensitivity, and quantitative methods for assessing CCVA, (ii) adaptive capacity and qualitative approaches, (iii) CCVA integrated approaches by combining participatory methods to quantitative ones, and (iv) collaboration and participation issues related to global change. The co-citation analysis showed that highly cited research terms were related to adaptation, exposure factors, and related changes and global change. This bibliometric analysis has provided an overall picture on the CCVA research field, particularly highlighting its utility for climate change adaptation. 相似文献
174.
Huaiyang Zhong Xiaocheng Li David Lobell Stefano Ermon Margaret L. Brandeau 《The Environmentalist》2018,38(4):458-470
Eradicating hunger and malnutrition is a key development goal of the twenty first century. This paper addresses the problem of optimally identifying seed varieties to reliably increase crop yield within a risk-sensitive decision making framework. Specifically, a novel hierarchical machine learning mechanism for predicting crop yield (the yield of different seed varieties of the same crop) is introduced. This prediction mechanism is then integrated with a weather forecasting model and three different approaches for decision making under uncertainty to select seed varieties for planting so as to balance yield maximization and risk. The model was applied to the problem of soybean variety selection given in the 2016 Syngenta Crop Challenge. The prediction model achieved a median absolute error of 235 kg/ha and thus provides good estimates for input into the decision models. The decision models identified the selection of soybean varieties that appropriately balance yield and risk as a function of the farmer’s risk aversion level. More generally, the models can support farmers in decision making about which seed varieties to plant. 相似文献
175.
Nadia Marchettini Margherita Panzieri Valentina Niccolucci Simone Bastianoni Stefano Borsa 《国际发展与全球生态学杂志》2013,20(3):275-282
Increased awareness of the importance of environmental protection and the introduction of international standards like ISO 14001 stimulated development of environmental sustainability indicators as a means to measure systems environmental performance. Here, a thermodynamic approach, emergy analysis (Odum, 1988) was used to obtain sustainability indicators able to analyse and quantify the productive and ecological performance of four famous Italian wine productions: Chianti, Brunello di Montalcino, Nobile di Montepulciano, and Barbera d'hti. The application to agricultural production was motivated by the growing need for productive and environmentally sound development in modern agriculture, in which the resource base, the environment, is preserved. The choice of wines, more precisely, grape production, is due to their importance for Italian agriculture and the economy. All the wines demonstrated a good long-term environmental sustainability, especially in view of their high quality and in comparison with the average Italian wine production. Emergy analysis proved a powerful tool for assessing environmental performance of these systems, and its use could easily be extended to other wine productions to obtain a form of environmental performance classification of this product. Systematic use of emergy analysis to assess environmental performance of different processes and products, not necessarily in agriculture, could be useful for environmental certification. 相似文献
176.
177.
The fine link between a particular dive pattern and a specific prey item represents a challenging task in the analysis of
marine predator–prey relationships. There is growing evidence that prey type affects diving seabirds’ foraging strategies,
dive shapes and underwater activity costs. This study investigates whether a generalist diver, the Great Cormorant Phalacrocorax carbo, modifies the time budget allocated to prey-capture behaviour and breathing strategies (reactive vs. anticipatory) with respect
to the prey type (pelagic vs. benthic). Video recordings of 91 Great Cormorants show how the ecology and behaviour of their
main prey, Mullets (Mugilidae) and Flounders Platichthys flesus, affect dive/surface durations and the diving pattern. The demersal habit and the low mobility of Flounders leads to an easy
access to prey with an anticipatory strategy. Moreover, the patchy distribution of this fish species increases prey-capture
rates. Conversely, Mullets exploit the whole water column and are highly mobile, and this is reflected in the need of performing
two sequential dives to capture a prey, both longer and likely more expensive, with a consequent switch of strategy from reactive
in the searching phase to anticipatory breathing during prey-capture events. This study provides evidence that a generalist
diver may switch between different foraging strategies, and it shows how each of them may be optimal under particular ecological
conditions. These constraints influence the dynamics that operate within the marine food chains and have relevant implications
in managing lagoon areas, including fish ponds. 相似文献
178.
Stefano?Antonio?GattoneEmail authorView authors OrcID profile Paolo?Giordani Tonio?Di?Battista Francesca?Fortuna 《Environmental and Ecological Statistics》2018,25(1):125-138
The implementation of an adaptive cluster sampling design often becomes logistically challenging because variation in the final sampling effort introduces uncertainty in survey planning. To overcome this drawback, an inexpensive and easy to measure auxiliary variable could be used in a two-phase survey strategy, called adaptive cluster double sampling (Félix-Medina and Thompson in Biometrika 91:877–891, 2004). In this paper, a two-phase sampling strategy is proposed which combines the idea of adaptive cluster double sampling with the principle of post-stratification. In the first-phase an adaptive cluster sample is selected by means of an inexpensive auxiliary variable. Networks from the first phase sampling are then post-stratified according to their size. In the second-phase, the network structure is used to select a subsample of units by means of stratified random sampling. The proposed sampling strategy employs stratification without requiring an a priori delineation of the strata. Indeed, the strata sizes are estimated in the course of the two-phase sampling process. Therefore, it is suitable for situations where stratification is suspected to be efficient but strata cannot be easily delineated in advance. In this framework, a new type of estimator for the population mean which mimics the stratified sampling mean estimator and an estimator of the sampling variance are proposed. The results of a simulation study confirm, as expected, that the use of post-stratification leads to gain in precision for the estimator. The proposed sampling strategy is applied for targeting an epiphytic lichen community Lobarion pulmonariae in a forest area of the Northern Apennines (N-Italy), characterized by several species of conservation concern. 相似文献
179.
We investigate turbulent mixing in a tidally driven, mid-latitude, shallow-water basin. The study is carried out numerically
at a laboratory-scale, using large-eddy simulation. We compared the results of the simulation with those of a correspondent
purely oscillatory flow (Stokes boundary layer). The effect of rotation on the flow dynamics is twofold. First, rotation gives
rise to a mean spanwise flow that concurs to redistribute the turbulent energy among the Reynolds stresses, in particular
between the horizontal directions, thus increasing the mixing across the water column and thickening the layer where developed
turbulence is observable. Second, the presence of the horizontal component of the background vorticity (latitude effect) breaks
the symmetry between the two semi-cycles of the oscillation, since turbulence results suppressed/enhanced during the first/second
semi-cycle. These two effects significantly modify the turbulent characteristics with respect to the purely oscillating flow,
although the mechanisms that generates turbulence present similar features. The qualitative agreement between our results
and some measurements carried out in two sites with characteristics similar to the case analyzed suggests that the outcomes
here provided may be of general use for the analysis of mid-latitude, neutrally stratified, shallow-water basins mainly driven
by semi-diurnal tidal currents. 相似文献
180.
Stefano Capuzzi Leonardo Capra Luca Romano 《International Journal of Sustainable Engineering》2019,12(1):38-46
The process used to obtain recycled Al alloys depends on the scrap quality. Rotary furnaces are normally used in Europe as they allow a great productivity and they can process low quality scrap using a salt flux to protect the molten metal from oxidation. In this article, the effect of the quantity of salt on the metal recovery has been experimentally investigated by melting several types of scrap under a mixture of NaCl–KCl–Na3AlF6 salts. The quantity of salt has been related to the salt factor (SF), which is the ratio between the non-metallic content in the scrap and the quantity of salt required. The same levels of salt factor have been tested by melting the scrap in rotary and crucible furnaces. The metal recovery increases with the salt content for both furnaces. The results obtained with the different melting processes are comparable because the yield difference is similar considering different salt factors. Crucible furnace gives greater metal recovery but it cannot replace rotary furnace in Al refining industry due to lower melting capacity. However, the results highlight that the optimisation of the Al refining process can be supported by preliminary tests through crucible furnaces reducing the time and material consumptions. 相似文献