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101.
102.
David W. Pfennig George R. HarperJr Abel F. Brumo William R. Harcombe Karin S. Pfennig 《Behavioral ecology and sociobiology》2007,61(4):505-511
Batesian mimicry evolves when a palatable species, the “mimic,” resembles a dangerous species, the “model,” because both receive
protection from predation. Yet, this protection should break down where the model is absent, because predators in such areas
would not be under selection to avoid the model. Here, we test this prediction in a coral snake mimicry complex. We exposed
plasticine replicas of milk snakes that closely mimic coral snakes to natural predators to determine if good mimetic milk
snakes are preferentially attacked in allopatry with their model. Moreover, we evaluated whether attack rates on these replicas
varied among three different allopatric regions that differed in the type of mimic found locally (i.e., good mimic, poor mimic,
or no mimic). When all three regions were considered together, mimics were not preferentially attacked. When regions were
analyzed separately, however, attacks on mimics were significantly greater than randomness only where good mimics were found.
These variable levels of predation on good mimics might reflect frequency-dependent (i.e., apostatic) predation. In allopatric
regions where good mimics are present, predators might have learned or evolved preferences for conspicuous, palatable prey
that they encounter frequently. By contrast, in allopatric regions where good mimics are absent, predators might not have
learned or evolved preferences for novel phenotypes. Thus, when predation is frequency-dependent, as long as good mimics are
rare, they might not experience elevated levels of predation in allopatry with their model as predicted by the Batesian mimicry
hypothesis. 相似文献
103.
Towards a Formal Framework of Vulnerability to Climate Change 总被引:7,自引:0,他引:7
Cezar Ionescu Richard J. T. Klein Jochen Hinkel K. S. Kavi Kumar Rupert Klein 《Environmental Modeling and Assessment》2009,14(1):1-16
There is confusion regarding the notion of “vulnerability” in the climate change scientific community. Recent research has
identified a need for formalisation, which would support accurate communication and the elimination of misunderstandings that
result from the use of ambiguous terminology. Moreover, a formal framework of vulnerability is a prerequisite for computational
approaches to its assessment. This paper presents an attempt at developing such a formal framework. We see vulnerability as
a relative concept in the sense that accurate statements about vulnerability are possible only if one clearly specifies (1)
the entity that is vulnerable, (2) the stimulus to which it is vulnerable and (3) the preference criteria to evaluate the
outcome of the interaction between the entity and the stimulus. We relate the resulting framework to the Intergovernmental
Panel on Climate Change conceptualisation of vulnerability and two recent vulnerability studies.
This paper is dedicated to the memory of Gerhard Petschel-Held, whose pioneering work on syndromes of global change has been
a source of inspiration for us and for others across various schools of thought on vulnerability. 相似文献
104.
Herman J. Haring Mark E. Smith James M. Lazorchak Philip A. Crocker Abel Euresti Karen Blocksom Melissa C. Wratschko Michael C. Schaub 《Environmental monitoring and assessment》2012,184(12):7343-7351
Elutriate bioassays are among numerous methods that exist for assessing the potential toxicity of sediments in aquatic systems. In this study, interlaboratory results were compared from 96-h Ceriodaphnia dubia and Pimephales promelas static-renewal acute toxicity tests conducted independently by two laboratories using elutriate samples prepared from the same sediment. The goal of the study was to determine if the results from the elutriate tests were comparable between two U.S. Environmental Protection Agency (USEPA) laboratories when different elutriate preparation procedures were employed by each lab. Complete agreement in site characterization was attained in 22 of the 25 samples for both bioassays amongst each lab. Of the 25 samples analyzed, 10 were found to be toxic to at least one of the species tested by either laboratory. The C. dubia elutriate tests conducted by the National Exposure Research Laboratory (NERL) indicated that 7 of the 25 sediment samples were toxic, while 8 sediment samples were characterized as such in testing conducted by USEPA Region 6 (Region 6). The P. promelas elutriate tests conducted by NERL determined 8 samples as toxic, while Region 6 tests displayed toxicity in 5 of the samples. McNemar's test of symmetry for C. dubia (S?=?0.33, p?=?0.5637) and P. promelas (S?=?3.0, p?=?0.0833) tests indicated no significant differences in designating a site toxic between NERL and Region 6 laboratories. Likewise, Cohen's kappa test revealed significant agreement between NERL and Region 6 C. dubia (K?=?0.7148, p?<?0.01) and P. promelas (K?=?0.6939, p?<?0.01) elutriate tests. The authors conclude that differences in interlaboratory elutriate preparation procedures have no bearing on the ability of either the C. dubia or P. promelas bioassay testing methods to detect toxicity while yielding similar results. 相似文献
105.
106.
The use of the adsorbent styrenedivinylbenzene-reverse phase sulfonated (SDB-RPD) Empore disk in a chemcatcher type passive sampler is routinely applied in Australia when monitoring herbicides in aquatic environments. One key challenge in the use of passive samplers is mitigating the potentially confounding effects of varying flow conditions on chemical uptake by the passive sampler. Performance reference compounds (PRCs) may be applied to correct sampling rates (Rs) for site specific changed in flow and temperature however evidence suggests the use of PRCs is unreliable when applied to adsorbent passive samplers. The use of the passive flow monitor (PFM) has been introduced for the assessment of site-specific changes in water flow. In the presented study we have demonstrated that the Rs at which both atrazine and prometryn are accumulated within the SDB-RPD-Empore disk is dependent on the flow conditions. Further, the calibration of the measured Rs for chemical uptake by the SDB-RPD-Empore disk to the mass lost from the PFM has shown that the PFM provides an accurate measure of Rs for flow velocities from 0 to 16 cm s−1. Notably, for flow rates >16 cm s−1, a non linear increase in the Rs of both herbicides was observed which indicates that the key resistance to uptake into the SDB-RPD Empore disk is associated with the diffusion through the overlying diffusion limiting membrane. Overall the greatest uncertainty remains at very low flow conditions, which are unlikely to often occur in surface waters. Validation of the PFM use has also been undertaken in a limited field study. 相似文献
107.
O'Brien D Hawker D Shaw M Mueller JF 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1435-1441
Passive samplers are typically calibrated under constant flow and concentration conditions. This study assessed whether concentration and/or flow pulses could be integrated using a phosphate passive sampler (P-sampler). Assessment involved three 21-day experiments featuring a pulse in flow rate, a pulse of filterable reactive phosphate (FRP) concentration and a simultaneous concentration and flow pulse. FRP concentrations were also determined by parallel grab sampling and the P-sampler calibrated with passive flow monitors (PFMs) and direct measurement of flow rates. The mass lost from the PFM over the deployment periods predicted water velocity to within 5.1, 0.48 and 7.1% when exposed to a flow rate pulse (7.5-50 cm s−1), concentration pulse (5-100 μg P L−1), or both simultaneously. For the P-sampler, good agreement was observed between the grab and passive measurements of FRP concentration when exposed to a pulse in flow (6% overestimation) or concentration (2% underestimation). 相似文献
108.
Ozer TB Erkaya IA Udoh AU Duygu DY Akbulut A Bayramoglu G Arica MY 《Environmental science and pollution research international》2011,19(7):2983-2993
Background and purpose
The biosorption of Cr(VI) from aqueous solution has been studied using free and immobilized Pediastrum boryanum cells in a batch system. The algal cells were immobilized in alginate and alginate?Cgelatin beads via entrapment, and their algal cell free counterparts were used as control systems during biosorption studies of Cr(VI).Methods
The changes in the functional groups of the biosorbents formulations were confirmed by Fourier transform infrared spectra. The effect of pH, equilibrium time, initial concentration of metal ions, and temperature on the biosorption of Cr(VI) ion was investigated.Results
The maximum Cr(VI) biosorption capacities were found to be 17.3, 6.73, 14.0, 23.8, and 29.6?mg/g for the free algal cells, and alginate, alginate?Cgelatin, alginate?Ccells, and alginate?Cgelatin?Ccells at pH?2.0, which are corresponding to an initial Cr(VI) concentration of 400?mg/L. The biosorption of Cr(VI) on all the tested biosorbents (P. boryanum cells, alginate, alginate?Cgelatin, and alginate?Ccells, alginate?Cgelatin?Ccells) followed Langmuir adsorption isotherm model.Conclusion
The thermodynamic studies indicated that the biosorption process was spontaneous and endothermic in nature under studied conditions. For all the tested biosorbents, biosorption kinetic was best described by the pseudo-second-order model. 相似文献109.
Rainer Steinbrecher Gerhard Smiatek Renate Köble Günther Seufert Jochen Theloke Karin Hauff Paolo Ciccioli Robert Vautard Gabriele Curci 《Atmospheric environment (Oxford, England : 1994)》2009,43(7):1380-1391
Biogenic VOC emission estimates from the earth's surface are crucial input parameters in air quality models. Knowledge accumulated in the last years about BVOC source distributions and chemical compound species emission profiles in Europe as well as the demand of air quality modellers for a finer resolution in space and time of BVOC estimates have led to the set-up of new emission modelling systems. An updated fast BVOC emission modelling platform explicitly considering the seasonality of emission potentials and leaf temperature gradients in forest canopies by the semi-empirical emission module (seBVOC) will be proposed and used for estimating hourly values of chemical compound-specific emissions in Europe (33–68° north; 10° west to 40° east) in the years 1997, 2000, 2001, and 2003. Spatial resolution will be 10 km by 10 km. The database used contains latest land and forest distributions, updated foliar biomass densities, leaf area indices (LAI), and plant as well as chemical compound-specific emission potentials, if available. Meteorological input parameters for the respective years will be generated using the non-hydrostatic meteorological model MM5. Highest BVOC emissions occur in daytime hours around noon from the end of May to mid-August in the Mediterranean area and from the mid of June to the end of July in the boreal forests. Comparison of 3 BVOC model approaches will reveal that for July 2003, the European isoprene and monoterpene totals range from 1124 Gg to 1446 Gg and from 338 Gg to 1112 Gg, respectively. Small-scale deviations may be as high as ±0.6 Mg km?2 for July 2003, reflecting the current uncertainty range for BVOC estimates. Key sources of errors in inventories are still insufficiently detailed land use data for some areas and lacking chemically speciated plant-specific emission potentials in particular in boreal, south-eastern, and northern African landscapes. The hourly emissions of isoprene, speciated terpenes, and oxyVOC have been made available by the NatAir database. 相似文献
110.
König HJ Sghaier M Schuler J Abdeladhim M Helming K Tonneau JP Ounalli N Imbernon J Morris J Wiggering H 《Environmental management》2012,50(1):153-165
Environmental threats and progressive degradation of natural resources are considered critical impediments to sustainable development. This paper reports on a participatory impact assessment of alternative soil and water conservation (SWC) scenarios in the Oum Zessar watershed, Tunisia. The first objective was to assess the impact of three SWC scenarios on key social, economic and environmental land use functions. The second objective was to test and evaluate the applicability of the 'Framework for Participatory Impact Assessment (FoPIA)' for assessing scenario impacts in the context of a developing country, in this case Tunisia. The assessed scenarios included: the originally planned SWC policy implementation at 85 % coverage of arable land of the watershed, the current implementation (70 %), and a hypothetical expansion of SWC measures to the entire watershed (100 %). Our results suggest that implementation of the SWC policy at 100 % coverage of arable land achieves the maximum socioeconomic benefit. However, if stakeholders' preferences regarding land use functions are taken into account, and considering the fact that the implementation of SWC measures also implies some negative changes to traditional landscapes and the natural system, SWC implementation at 85 % coverage of arable land might be preferable. The FoPIA approved to be a useful tool for conducting a holistic sustainability impact assessment of SWC scenarios and for studying the most intriguing sustainability problems while providing possible recommendations towards sustainable development. We conclude that participatory impact assessment contributes to an enhanced regional understanding of key linkages between policy effects and sustainable development, which provides the foundation for improved policy decision making. 相似文献