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101.
Population growth in snow geese: a modeling approach integrating demographic and survey information 总被引:1,自引:0,他引:1
There are few analytic tools available to formally integrate information coming from population surveys and demographic studies. The Kalman filter is a procedure that facilitates such integration. Based on a state-space model, we can obtain a likelihood function for the survey data using a Kalman filter, which we may then combine with a likelihood for the demographic data. In this paper, we used this combined approach to analyze the population dynamics of a hunted species, the Greater Snow Goose (Chen caerulescens atlantica), and to examine the extent to which it can improve previous demographic population models. The state equation of the state-space model was a matrix population model with fecundity and regression parameters relating adult survival and harvest rate estimated in a previous capture-recapture study. The observation equation combined the output from this model with estimates from an annual spring photographic survey of the population. The maximum likelihood estimates of the regression parameters from the combined analysis differed little from the values of the original capture-recapture analysis, though their precision improved. The model output was found to be insensitive to a wide range of coefficient of variation (CV) in fecundity parameters. We found a close match between the surveyed and smoothed population size estimates generated by the Kalman filter over an 18-year period, and the estimated CV of the survey (0.078-0.150) was quite compatible with its assumed value (approximately 0.10). When we used the updated parameter values to predict future population size, the model underestimated the surveyed population size by 18% over a three-year period. However, this could be explained by a concurrent change in the survey method. We conclude that the Kalman filter is a promising approach to forecast population change because it incorporates survey information in a formal way compared with ad hoc approaches that either neglect this information or require some parameter or model tuning. 相似文献
102.
The release of bound [14C] atrazine residues and their uptake by maize plants was investigated. “Natural”; humic acids, extracted from a brown soil, and “model”; humic acids, prepared from catechol, both containing bound [14C] atrazine residues were incubated with plants in soil. After 21 days, the maize plants contained 0.7% (plants grown in soil mixed with “natural”; humic acids) to 1.7% (plants grown in soil mixed with “model”; humic acids) of the radioactivity originally introduced. The roots contained 55 to 70% of the [14C] residues whereas the remainder was present in the shoots. A significant amount of the total [14C] residues (29 to 53%) became again bound in plant tissues, whereas the, majority of extractable [14C] residues was present in the form of conjugates. The behaviour of “model”; humic acid‐bound residues was comparable to that of “natural”; humic acid‐bound residues or soil‐bound residues. 相似文献
103.
Organochlorine pollution in tropical rivers (Guadeloupe): role of ecological factors in food web bioaccumulation 总被引:2,自引:0,他引:2
Coat S Monti D Legendre P Bouchon C Massat F Lepoint G 《Environmental pollution (Barking, Essex : 1987)》2011,159(6):1692-1701
Concentrations of organochlorine pesticides and stable isotope ratios of nitrogen and carbon were measured in a tropical freshwater ecosystem to evaluate the contamination level of biota and examine the bioaccumulation patterns of pollutants through the food web. Chemical analyses showed a general and heavy contamination of the entire food web. They revealed the strong accumulation of pollutants by juveniles of diadromous fishes and shrimps, as they re-enter the river. The role of ecological factors in the bioaccumulation of pesticides was evaluated. Whereas the most persistent pollutants (chlordecone and monohydro-chlordecone) were related to the organisms diet and habitat, bioaccumulation of β-HCH was only influenced by animal lipid content. The biomagnification potential of chlordecone through the food chain has been demonstrated. It highlighted the importance of trophic transfer in this compound bioaccumulation process. In contrast, bioconcentration by passive diffusion from water seemed to be the main exposure route of biota to β-HCH. 相似文献
104.
Monitoring plastic ingestion by the northern fulmar Fulmarus glacialis in the North Sea 总被引:1,自引:0,他引:1
van Franeker JA Blaize C Danielsen J Fairclough K Gollan J Guse N Hansen PL Heubeck M Jensen JK Le Guillou G Olsen B Olsen KO Pedersen J Stienen EW Turner DM 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2609-2615
The abundance of plastics in stomachs of northern fulmars from the North Sea is used in the OSPAR Ecological Quality Objective (EcoQO) for marine litter. The preliminary EcoQO defines acceptable ecological quality as the situation where no more than 10% of fulmars exceed a critical level of 0.1 g of plastic in the stomach. During 2003-2007, 95% of 1295 fulmars sampled in the North Sea had plastic in the stomach (on average 35 pieces weighing 0.31 g) and the critical level of 0.1 g of plastic was exceeded by 58% of birds, with regional variations ranging from 48 to 78%. Long term data for the Netherlands since the 1980s show a decrease of industrial, but an increase of user plastics, with shipping and fisheries as the main sources. The EcoQO is now also used as an indicator for Good Environmental Status in the European Marine Strategy Framework Directive. 相似文献
105.
The solar energy received by a flat plate collector is calculated for various tracking modes: fixed, inclination depending on the season or the month; variable inclination with fixed azimuth, variable azimuth with fixed inclination and double tracking. At first, we take into account only the sun position and then, we use validated radiation models for estimating the ground solar radiation. Using a tracker is questionable particularly if the additional costs are taken into account. A good solution to increase the available solar energy is to change seasonally the inclination, that is, 4 times per year. 相似文献
106.
The study deals with the problem of evaluating management strategies for pure stands of Norway spruce (Picea abies Karst) to balance adaptation to and mitigation of climate change, taking into account multiple objectives of a forest owner.
A simulation and optimization approach was used to evaluate the management of a 1000 ha model Age-Class forest, representing
the age-class distribution of an area of 66,000 ha of pure Norway spruce forests in the Black Forest region of Southwest Germany.
Eight silvicultural scenarios comprising five forest conversion schemes which were interpreted as “adaptation” strategies
which aims at increasing the proportion of Beech, that is expected to better cope with climate change than the existing Norway
spruce, and three conventional strategies including a “Do-nothing” alternative classified as “mitigation”, trying to keep
rather higher levels of growing stock of spruce, were simulated using the empirical growth simulator BWINPro-S. A linear programming
approach was adapted to simultaneously maximize the net present values of carbon sequestration and timber production subject
to the two constraints of wood even flow and partial protection of the oldest (nature protection). The optimized plan, with
the global utility of 11,687 €/ha in forty years, allocated a combination of silvicultural scenarios to the entire forest
area. Overall, strategies classified as “mitigation” were favored, while strategies falling into the “adaptation”-category
were limited to the youngest age-classes in the optimal solution. Carbon sequestration of the “Do-nothing” alternative was
between 1.72 and 1.85 million tons higher than the other alternatives for the entire forest area while the differences between
the adaptation and mitigation approaches were approximately 133,000 tons. Sensitivity analysis showed that a carbon price
of 21 €/t is the threshold at which carbon sequestration is promoted, while an interest rate of above 2% would decrease the amount
of carbon. 相似文献
107.
The current study examines the possibility that agency workers can experience perceived insider status despite their assumed “outsider” category. One hundred ninety‐one agency workers from Canadian financial firms completed surveys assessing agency worker perceptions regarding the level of support from both their supervisors and the client firms' permanent workers, as well as the agency workers' level of perceived insider status and affective commitment toward the client firm. Agency worker supervisors (within the client firm) assessed the agency workers' level of interpersonal facilitation. Results indicate that: (1) Agency workers can experience perceived insider status, regardless of their objective classification as outsiders; (2) perceived support from supervisors and the client firms' permanent workers contribute to agency worker perceptions of insider status; and (3) perceptions of insider status are associated with higher levels of both affective commitment and interpersonal facilitation, even in workers that are considered marginally tied to the organization. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
108.
Dissolved organic matter from treated effluent of a major wastewater treatment plant: characterization and influence on copper toxicity 总被引:1,自引:0,他引:1
Pernet-Coudrier B Clouzot L Varrault G Tusseau-Vuillemin MH Verger A Mouchel JM 《Chemosphere》2008,73(4):593-599
A combination of reverse osmosis (RO) concentration and DAX-8/XAD-4 resin adsorption techniques is used to isolate the various constituents of urban dissolved organic matter (DOM) from inorganic salts. Three fractions: hydrophobic (HPO), transphilic (TPI) and hydrophilic (HPI) accounting respectively for 35%, 20% and 45% of extracted carbon, are isolated from effluents of a major French wastewater treatment plant. This atypical DOC distribution, in comparison with natural water where the HPO fraction dominates, shows the significance of HPI fraction which often gets neglected because of extraction difficulties. A number of analytical techniques (elemental, spectroscopic: UV, FTIR) allow highlighting the weak aromaticity of wastewater effluent DOM (EfOM) due to fewer degradation and condensation processes and the strong presence of proteinaceous structures indicative of intense microbial activity. Copper toxicity in the presence of DOM is estimated using an acute toxicity test on Daphnia Magna (Strauss). Results reveal the similar protective role of each EfOM fraction compared to reference Suwannee river fulvic acid despite lower EfOM aromaticity (i.e. specific UV absorbance). The environmental implications of these results are discussed with respect to the development of site-specific water quality criteria. 相似文献
109.
For 503 days, unoiled control and artificially oiled sediments were incubated in situ at 20m water depth in a Mediterranean coastal area. Degradation of the aliphatic fraction of the oil added was followed by GC-MS. At the same time, terminal restriction fragment length polymorphism (T-RFLP) of 16S rRNA encoding genes was used to detect dynamics in the sulfate-reducing bacteria (SRB) community in response to the oil contamination. Specific polymerase chain reaction (PCR) primer sets for five generic or suprageneric groups of SRB were used for PCR amplification of DNA extracted from sediments. During the experiment, hydrocarbons from C(17) to C(30) were significantly degraded even in strictly anoxic sediment layers. Of the five SRB groups, only two groups were detected in the sediments (control and oiled), namely the Desulfococcus-Desulfonema-Desulfosarcina-like group and the Desulfovibrio-Desulfomicrobium-like group. Statistical analysis of community patterns revealed dynamic changes over time within these two groups following the contamination. Significant differences in community patterns were recorded in artificially oiled compared with control sediments. Cloning and sequencing of 16S rRNA encoding genes performed after 503 days showed that many of the most abundant sequences were closely related to hydrocarbonoclastic SRB which could have played an active role in the observed biodegradation of aliphatic hydrocarbons. Results from the present study provide useful information on the dynamics of dominant SRB in heavily oil-contaminated sediments and their potential for anaerobic biodegradation for the treatment of spilled oil in anoxic marine environments. 相似文献
110.
Ehrich Dorothée Schmidt Niels M. Gauthier Gilles Alisauskas Ray Angerbjörn Anders Clark Karin Ecke Frauke Eide Nina E. Framstad Erik Frandsen Jay Franke Alastair Gilg Olivier Giroux Marie-Andrée Henttonen Heikki Hörnfeldt Birger Ims Rolf A. Kataev Gennadiy D. Kharitonov Sergey P. Killengreen Siw T. Krebs Charles J. Lanctot Richard B. Lecomte Nicolas Menyushina Irina E. Morris Douglas W. Morrisson Guy Oksanen Lauri Oksanen Tarja Olofsson Johan Pokrovsky Ivan G. Popov Igor Yu. Reid Donald Roth James D. Saalfeld Sarah T. Samelius Gustaf Sittler Benoit Sleptsov Sergey M. Smith Paul A. Sokolov Aleksandr A. Sokolova Natalya A. Soloviev Mikhail Y. Solovyeva Diana V. 《Ambio》2020,49(3):801-804
Ambio - In the original published article, some of the symbols in figure 1A were modified incorrectly during the typesetting and publication process. The correct version of the figure is provided... 相似文献