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941.
Iñaki Rodríguez-Prieto José Martín Esteban Fernández-Juricic 《Behavioral ecology and sociobiology》2010,64(12):1937-1945
Habituation to nonlethal predation stimuli may provide benefits for animals living in areas with frequent encounters with
low-risk predators. On the other hand, individuals can be very consistent in their antipredator responses, with shy individuals
showing greater degree of responsiveness than bold individuals. However, the link between habituation or boldness and individual
benefits has not been thoroughly investigated. We established whether and how two behavioral components associated with antipredator
responses (habituation and boldness, and their interaction) would influence body condition, which is a parameter related to
fitness. We conducted an outdoor semi-natural experiment with Iberian wall lizards (Podarcis hispanica). Individual boldness was consistent across contexts, but we did not find any effect of boldness or the interaction between
boldness and habituation on body condition. However, those individuals that habituated more readily to a frequent predatory
stimulus were able to increase their body condition more relative to lizards that habituated less. This finding highlights
the importance of individual differences in behavioral plasticity, which could influence traits related to fitness. Habituation
can provide benefits for individuals exposed to low-risk predators; however, individuals more prone to habituation could also
experience mortality costs by wrongly habituating to a dangerous predator. 相似文献
942.
Jorge M. Mendes Patrícia Cortés de Zea Bermudez José Pereira K. F. Turkman M. J. P. Vasconcelos 《Environmental and Ecological Statistics》2010,17(1):1-28
In Portugal, due to the combination of climatological and ecological factors, large wildfires are a constant threat and due
to their economic impact, a big policy issue. In order to organize efficient fire fighting capacity and resource management,
correct quantification of the risk of large wildfires are needed. In this paper, we quantify the regional risk of large wildfire
sizes, by fitting a Generalized Pareto distribution to excesses over a suitably chosen high threshold. Spatio-temporal variations
are introduced into the model through model parameters with suitably chosen link functions. The inference on these models
are carried using Bayesian Hierarchical Models and Markov chain Monte Carlo methods. 相似文献
943.
944.
In the period of transition from communism, the countries of central and eastern Europe have made considerable efforts to adopt new environmental legislation and to create new institutions. However, the implementation of these powers, particularly at the level of local government, remains problematic. This article reviews the arguments for developing capacity for taking environmental action at the municipal level, and then examines the actual experience of one such country, the Slovak Republic. While Slovakia displays many of the features of policy making familiar to other transitional countries, it has faced some particular political problems. Recent legislation has given formal competencies in the field of environmental protection to local government, but it remains fragmented and relatively poorly resourced. Nevertheless, there is evidence that, through a combination of mutual support through national associations and the establishment of international links, local authorities are adopting a number of innovative approaches and strategies which should be better able to address the changing character of environmental problems. 相似文献
945.
Gómara B González MJ Baos R Hiraldo F Abad E Rivera J Jiménez B 《Environment international》2008,34(1):73-78
This study provides information on the current status of contamination by organochlorines (DDTs, PCBs, PCDDs and PCDFs) in the declining red kite (Milvus milvus L.) population breeding in the Do?ana National Park (DNP), south-western Spain. Analyses were performed in addled eggs collected between 1999 and 2001. DDE concentrations ranged from 0.1 to 33.5 microg/g ww, representing more than 86% of the total DDTs. Of the samples studied, 50% showed DDE levels above those associated with reproductive impairment in other raptor species. Concentrations of ortho PCBs (average 36.8 microg/g ww+/-37.7) in 50% of the eggs were much higher than levels reported to cause reduced hatching success, embryo mortality, and deformities in birds (>20 microg/g ww). It is remarkable that average ortho PCB and DDE concentrations showed an increase of one order of magnitude compared to previous data for the species during the 80s. Total PCDD/Fs showed levels in the low pg/g range (7.2-42 pg/g ww), having PCDDs and PCDFs similar contributions in most samples. Total mean TEQs were 238 pg/g (ww), being the range 7.02-667 pg/g (ww). Spatial variation within DNP was observed for PCBs, DDTs, as well as for TEQs. Since some eggs exceeded the NOEL (67%) and LOEL (33%) reported for other raptor species, we would expect the red kite to experience detrimental effects to dioxin-like toxicity. Our results suggest that organochlorine contaminants should be regarded as an element of concern in the population under study, in addition to other conservation problems already reported. Further investigations should be undertaken to identify potential sources of these chemicals in DNP, and to find out if organochlorine contamination is present in other predator species in the area, as well as their potential health effects on individuals and/or populations. 相似文献
946.
Gutiérrez-Villanueva JL Martín-Martín A Peña V Iniguez MP de Celis B de la Fuente R 《Journal of environmental radioactivity》2008,99(10):1520-1524
In situ gamma spectrometry provides a fast method to determine (137)Cs inventories in soils. To improve the accuracy of the estimates, one can use not only the information on the photopeak count rates but also on the peak to forward-scatter ratios. Before applying this procedure to field measurements, a calibration including several experimental simulations must be carried out in the laboratory. In this paper it is shown that Monte Carlo methods are a valuable tool to minimize the number of experimental measurements needed for the calibration. 相似文献
947.
Assessment of Self-Organizing Map artificial neural networks for the classification of sediment quality 总被引:3,自引:0,他引:3
Alvarez-Guerra M González-Piñuela C Andrés A Galán B Viguri JR 《Environment international》2008,34(6):782-790
The application of mathematical tools in initial steps of sediment quality assessment frameworks can be useful to provide an integrated interpretation of multiple measured variables. This study reveals that the Self-Organizing Map (SOM) artificial neural network can be an effective tool for the integration of multiple physical, chemical and ecotoxicological variables in order to classify different sites under study according to their similar sediment quality. Sediment samples from 40 sites of 3 estuaries of Cantabria (Spain) were classified with respect to 13 physical, chemical and toxicological variables using the SOM. Results obtained with the SOM, when compared to those of traditional multivariate statistical techniques commonly used in the field of sediment quality (principal component analysis (PCA) and hierarchical cluster analysis (HCA)), provided a more useful classification for further assessment steps. Especially, the powerful visualization tools of the SOM, which offer more information and in an easier way than HCA and PCA, facilitate the task of establishing an order of priority between the distinguished groups of sites depending on their need for further investigations or remediation actions in subsequent management steps. 相似文献
948.
The beneficial role of mycorrhizal association on plant nutrition and water supply is well-known, however, very little information exists with respect to the availability of radionuclides. We have measured the effect of controlled mycorrhizal association on the root uptake from soil and accumulation in leaves of three radionuclides. The radionuclides have contrasting chemical and biological properties: Cs is strongly adsorbed on soil, has no biological role and is a close analogue of potassium; Sr is less strongly adsorbed on soil and behaves very similarly to calcium; and Tc is very mobile in soil as pertechnetate, but immobilised when reduced to Tc(IV), it is also considered to be easily assimilated by biological systems. We found that mycorrhizal association had no effect on root-to-needle transfer of Cs, but increased root uptake and that this increase could not be explained by improved potassium nutrition. In contrast, the symbiotic relation decreased Tc soil-to-needle transfer, but this resulted from complex dynamics of root uptake and rapid immobilisation of Tc in soil. No effect of mycorrhizal association on Sr, like its stable analogue Ca, was observed. The addition of a phytotoxic metal, Cu, inhibited mycorrhizal association, thus eliminating the effects observed for non-contaminated plant-fungus couples, but had no additional effect on radionuclide dynamics. 相似文献
949.
The assessment of the particulate matter (PM) levels and its constituents presented in the atmosphere is an important requirement of the air quality management and air pollution abatement. The heavy metal levels in PM10 are commonly evaluated by experimental measurements; nevertheless, the EC Directives also allow the Regional Governments to estimate the regulated metal levels (Pb in Directive 2008/50/EC and As, Ni and Cd in Directive 2004/107/EC) by objective estimation and modelling techniques. These techniques are proper alternatives to the experimental determination because the required analysis and/or the number of required sampling sites are reduced. The present work aims to estimate the annual levels of regulated heavy metals by means of multivariate linear regression (MLR) and principal component regression (PCR) at four sites in the Cantabria region (Northern Spain). Since the objective estimation techniques may only be applied when the regulated metal concentrations are below to the lower assessment threshold, a previous evaluation of the determined annual levels of heavy metals is conducted to test the fulfilment of the EC Directives requirements. At the four studied sites, the results show that the objective estimations are allowed alternatives to the experimental determination. The annual average metal concentrations are well estimated by the MLR technique in all the studied sites; furthermore, the EC quality requirements for the objective estimations are fulfilled by the developed statistical MLR models. Hence these estimations may be used by Regional Governments as a proper alternative to the experimental measurements for the regulated metal levels assessment. 相似文献
950.
Raspini Jéssica Prats Bonfante Mariele Canal Cúnico Franciele Rossetti Alarcon Orestes Estevam Campos Lucila M. S. 《Journal of Material Cycles and Waste Management》2022,24(5):1747-1759
Journal of Material Cycles and Waste Management - The transition from the current linear to a circular economy (CE) is a great challenge, especially in industries where the theme was barely... 相似文献