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221.
The courtship and mounting behaviour of tortoises is elaborate, and based on a multiple signalling system involving visual, olfactory and acoustic signals. Vocalizations related to mounting seem to be particularly significant because tortoises vocalize mainly at this time. Vocalizations and courtship behaviour may be costly for males, and if these costs increase differentially for different males, then the potential exists for vocalizations and displays to reveal male individual quality. In this correlative study, we analysed relationships between male mounting success and morphological and behavioural traits, particularly acoustic signals, exhibited by male marginated tortoises (Testudo marginata) during courtship, in a group of 94 individuals breeding in semi-natural enclosures. For each male, we estimated general body condition, courtship intensity and mounting success; calls of mounting males were recorded and four sonagraphic features were measured. Calls differed significantly among males, and two features varied according to body condition. Male mounting success significantly increased according to the male/female size-ratio, suggesting the existence of a size-based assortative mating. Mounting success was also highly correlated with courtship intensity, measured as number of bites and rams given to females before mounting, and with number of calls emitted during mounting. Finally, mounting success was negatively related to call duration. To our knowledge, this is the first study in which features of tortoise vocalizations are shown to convey reliable information about male quality in socio-sexual contexts.Communicated by T. Czeschlik  相似文献   
222.
V, Co, Cu, Zn, As, Rb, Sr, Ag, Cd, Ba, Pb, Bi and U have been analysed by inductively coupled plasma sector field mass spectrometry in various sections of a dated snow/ice core drilled at an altitude of 6542 m on the Sajama ice cap in Bolivia. The analysed sections were dated from the Last Glacial Stage ( approximately 22,000 years ago), the Mid-Holocene and the last centuries. The observed variations of crustal enrichment factors (EFc) for the various metals show contrasting situations. For V, Co, Rb, Sr and U, EFc values close to unity are observed for all sections, then showing that these elements are mainly derived from rock and soil dust. For the other metals, clear time trends are observed, with a pronounced increase of EFc values during the 19th and 20th centuries. This increase shows evidence of metal pollution associated with human activity in South America. For Pb an important contribution was from gasoline additives. For metals such as Cu, Zn, Ag and Cd an important contribution was from metal production activities, with a continuous increase of production during the 20th century in countries such as Peru, Chile and Bolivia.  相似文献   
223.
Summary A paradigmatic model of the evolution of scientific thought encourages awareness of the provisional nature of present scientific explanations, sensitizing us to aspects of observed reality which they are unable to adequately explain. The self-organizing capabilities of open systems, exemplified by the clock-reactions investigated by Prigogine, not only demonstrate the inadequacies of the present probabilistic scientific interpretations but also point towards a more adequate model of scientific explanation which would place man at the centre of scientific development and encourage the integration of science.Dr Paolo Manzelli, as the senior author of this paper, is Professor in the Department of Chemistry at the University of Florence. John Eaton is responsible for Educational Studies at Farnborough College of Technology.  相似文献   
224.
A good water quality bio-indicator should be sensitive to different forms of water degradation in any geographical area, and effectively track water quality changes in time. We investigated whether the presence of a bird, the dipper (Cinclus cinclus), in 47 reaches of 35 streams of central Italy was affected by stream pollution as assessed by the Extended Biotic Index. Data from the literature and interviews with ornithologists furnished information about past dipper presence and water quality in the study streams. In 93.3% of cases dippers occurred in unpolluted reaches. The dipper was absent from 93.7% of polluted or strongly polluted streams. Dippers disappeared from 50% of the study streams for which past information was available. In a few streams dippers disappeared after the quality of water had degraded. Water quality degradation in the study area, especially in the hill streams, is causing dipper areale to contract to higher altitudes. Dipper is a good water quality bio-indicator for Mediterranean streams.  相似文献   
225.
When released after clock-shift, homing pigeons fail to orient towards the home direction but display a consistent deflection of their initial orientation due to the difference between the real sun azimuth and the computed azimuth according to the subjective time of each single bird. It has been reported that the size of the observed deflection is frequently smaller than expected and a discussion on the possible factors affecting the size of deflection has emerged. Some authors have proposed that the major factor in reducing the deflection after clock-shift is the simultaneous use of both the magnetic and the sun compasses, giving true and erroneous information, respectively, about the home direction. Therefore, a magnetic disturbance, by impeding the use of the geomagnetic information in determining the home direction, is presumed to increase the size of the deflection up to the levels of the expectation. To test this hypothesis, we released three groups of clock-shifted birds from unfamiliar locations (unmanipulated pigeons, pigeons bearing magnets on their head, and pigeons bearing magnets on their back) together with a group of unshifted control birds. As no difference in the orientation of the three groups emerged, we were not able to confirm the hypothesis of the role of the magnetic compass in reducing the expected deflection after clock-shift.Communicated by W. Wiltschko  相似文献   
226.
Increased urbanisation is leading to a rise in light pollution. Light pollution can disrupt the behaviour and physiology of animals resulting in increased mortality. However, animals may also benefit from artificial light sources, as these may aggregate prey or signal suitable environments. For example, spiders are commonly seen congregating around artificial light sources. Changes in selective pressures engendered by urban environments are driving changes in urban organisms, driving better adaptation to these environments. Here, we ask whether urban populations of the synanthropic spider Steatoda triangulosa show different responses to light compared to rural populations. Egg-sacs from urban and rural populations were collected and incubated in a common garden setting, and the emerging spiderlings tested for light preference. While rural spiderlings avoided light (37% built webs in the light), urban spiderlings were indifferent to it (49% built webs in the light). Reduced light avoidance may benefit spiders through increased prey capture, increased movement into suitable habitats, or due to a release from selection pressure from visually hunting predators which do not enter buildings.  相似文献   
227.
Soil erosion and associated off-site environmental impacts have attracted increasing attention in recent decades, and there is a growing need for reliable information on rates of soil loss. The potential for using 137Cs fallout to quantify rates and patterns of soil redistribution over medium-term timescales (ca. 45 years) has been successfully demonstrated in a wide range of environments around the world. The similar behaviour of fallout 210Pb in soils offers potential for its use as an alternative to 137Cs, in areas where 137Cs inventories are low or are complicated by additional fallout from the Chernobyl accident. There have, however, to date been few attempts to validate the use of fallout 210Pb measurements for assessing erosion rates. This paper reports an attempt to explore the use of fallout 210Pb to estimate rates of water-induced soil erosion on uncultivated land. It focuses on three small forest/rangeland catchments located in Calabria, southern Italy, for which measurements of sediment output are available. Comparison of the estimates of net soil loss from the catchments derived from 210Pb measurements with the measured sediment output, confirmed the validity of the 210Pb approach. The soil redistribution rates estimated using 210Pb measurements were also consistent with equivalent estimates obtained for the same study catchments using 137Cs measurements.  相似文献   
228.
Ecological Footprint Analysis (EFA) is an environmental accounting system, in physical unit, able to quantify the total amount of ecosystem resources required by a region or by a production process. This methodology is both scientifically robust and widely diffused for territorial and productive analysis. The application of EFA to agricultural systems are still uncommon and examples in the fruit sector rare.In this work a detailed application of EFA to an experimental trial in a commercial nectarine orchard in Piedmont (Italy) is presented. The field trial is focused on the evaluation of agronomical benefit of various kinds of swine manure for fertilizing orchards. Four productive systems were established from 2008: liquid slurry (LS), covered slurry (CS), solid fraction (SF), mineral nutrition (MN). All the environmental impacts of the four systems were quantified both directly on field and with extrapolations from farmer knowledge. As previous studies suggested, we considered not only the one-year field operations, but also the whole lifetime of the orchard. The environmental costs of each system are presented and related to each other on the basis of their relative footprint value.Results highlight almost the same ecological footprint for the three manure fertilized systems (LS, CS and SF) with average of 0.96 gha t−1) and the highest ecological footprint can be found in the MN system (1.14 gha t−1). Interesting remarks can be done comparing the contributions to the ecological footprint of the field operations related to fertilization in the four systems. In the manure fertilized systems the fertilizer contribution goes from 0.9% to 1.2% of the total ecological footprint; but in the MN system the fertilizer contribution is 6.6% of the total ecological footprint. Results support the hypothesis that internal recycle and connections among different systems increasingly resulted in high system benefit and sustainability.  相似文献   
229.
The current paper discusses the topic of marine storm impact along European coastlines, presenting results from two FP7 Projects currently focusing on this topic, one working on the physical aspects of the problem (MICORE) and the other one on the socio-economic implications (ConHaz).The MICORE Project aims to provide on-line predictions of storm-related physical hazards (hydrodynamic as well as morphodynamic). The ConHaz Project addresses the socio-economic implications should these (or other) hazards actually materialize. Together these projects aim to deliver crucial information for emergency response efforts, while realizing the practical limitations for information processing and dissemination during crisis situations.The MICORE Project has developed and demonstrated on-line tools for reliable predictions of the morphological impact of marine storm events in support of civil protection mitigation strategies. The project specifically targeted the development of early warning and information systems to support short term emergency response in case of an extreme storm event. The current paper discusses in detail the outcome of an activity of databasing historical storm data. No clear changes in storminess were observed, except for some storm proxies (e.g. surges) and only at some locations (e.g. northern Adriatic, southern Baltic, etc.).The ConHaz Project undertook a desktop study of the methods normally used for evaluating the impact of marine storms and the associated coastal hazards considering direct costs, costs due to disruption of production processes, indirect costs, intangible costs, and costs of adaptation and mitigation measures. Several methods for cost estimation were reviewed. From the review it emerged that normally end-users only evaluate direct costs after the storms, while the cost of adaptation and mitigation measures is only done strategically in the context of Integrated Coastal Zone Management plans. As there is no standardized method for cost evaluations in this field, it is suggested that clear guidelines should be produced on the basis of simplicity for use by end-users. The integration between historical databases of the physical parameters of storms and detailed cost evaluation information would support the development of a knowledge background in end-users and justify the development of adaptation strategies.  相似文献   
230.
Atherina boyeri is a common inhabitant of the Mediterranean brackish and coastal waters. Several recent studies proposed the recognition of three distinct forms/species (one lagoon/freshwater and two marine) within an A. boyeri complex. In this study, we used 10 newly available microsatellite loci to better define the genetic structure of the lagoon form. A total of 428 fishes from 11 lagoons along the Italian and Albanian coasts and three Italian lakes were analyzed. A pronounced genetic spatial structure was confirmed for all considered geographic scales (near, medium and broad). A restricted gene flow was detected, suggesting reduced population connectivity. The comparison of present data and previous studies, based on mtDNA and RAPD markers, allowed a preliminary identification of the roles of recent factors (gene flow, habitat discontinuity and water currents) and past events (e.g., Pleistocene glaciations) in shaping the pattern of genetic differentiation.  相似文献   
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