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1.
We develop a landscape stewardship classification which distinguishes between farmers’ understanding of landscape stewardship, their landscape values, and land management actions. Forty semi-structured interviews were conducted with small-holder (<5 acres), medium-holders (5–100 acres), and large-holders (>100 acres) in South-West Devon, UK. Thematic analysis revealed four types of stewardship understandings: (1) an environmental frame which emphasized the farmers’ role in conserving or restoring wildlife; (2) a primary production frame which emphasized the farmers’ role in taking care of primary production assets; (3) a holistic frame focusing on farmers’ role as a conservationist, primary producer, and manager of a range of landscape values, and; (4) an instrumental frame focusing on the financial benefits associated with compliance with agri-environmental schemes. We compare the landscape values and land management actions that emerged across stewardship types, and discuss the global implications of the landscape stewardship classification for the engagement of farmers in landscape management.  相似文献   

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Jensen P  Andersson L 《Ambio》2005,34(4-5):320-324
Animal behavior is a central part of animal welfare, a keystone in sustainable animal breeding. During domestication, animals have adapted with respect to behavior and an array of other traits. We compared the behavior of junglefowl and White Leghorn layers, selected for egg production (and indirectly for growth). Jungle-fowl had a more active behavior in social, exploratory, anti-predatory, and feeding tests. A genome scan for Quantitative Trait Loci (QTLs) in a junglefowl x White Leghorn intercross revealed several significant or suggestive QTLs for different traits. Some production QTLs coincided with QTLs for behavior, suggesting that pleiotropic effects may be important for the development of domestication phenotypes. One gene has been located, which has a strong effect on the risk of being a victim of feather pecking, a detrimental behavior disorder. Modern genomics paired with analysis of behavior may help in designing more sustainable and robust breeding in the future.  相似文献   

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Michael R. Coughlan 《Ambio》2015,44(8):705-717
Fire-use and the scale and character of its effects on landscapes remain hotly debated in the paleo- and historical-fire literature. Since the second half of the nineteenth century, anthropology and geography have played important roles in providing theoretical propositions and testable hypotheses for advancing understandings of the ecological role of human–fire-use in landscape histories. This article reviews some of the most salient and persistent theoretical propositions and hypotheses concerning the role of humans in historical fire ecology. The review discusses this history in light of current research agendas, such as those offered by pyrogeography. The review suggests that a more theoretically cognizant historical fire ecology should strive to operationalize transdisciplinary theory capable of addressing the role of human variability in the evolutionary history of landscapes. To facilitate this process, researchers should focus attention on integrating more current human ecology theory into transdisciplinary research agendas.  相似文献   

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Biological and physical processes in the Arctic system operate at various temporal and spatial scales to impact large-scale feedbacks and interactions with the earth system. There are four main potential feedback mechanisms between the impacts of climate change on the Arctic and the global climate system: albedo, greenhouse gas emissions or uptake by ecosystems, greenhouse gas emissions from methane hydrates, and increased freshwater fluxes that could affect the thermohaline circulation. All these feedbacks are controlled to some extent by changes in ecosystem distribution and character and particularly by large-scale movement of vegetation zones. Indications from a few, full annual measurements of CO2 fluxes are that currently the source areas exceed sink areas in geographical distribution. The little available information on CH4 sources indicates that emissions at the landscape level are of great importance for the total greenhouse balance of the circumpolar North. Energy and water balances of Arctic landscapes are also important feedback mechanisms in a changing climate. Increasing density and spatial expansion of vegetation will cause a lowering of the albedo and more energy to be absorbed on the ground. This effect is likely to exceed the negative feedback of increased C sequestration in greater primary productivity resulting from the displacements of areas of polar desert by tundra, and areas of tundra by forest. The degradation of permafrost has complex consequences for trace gas dynamics. In areas of discontinuous permafrost, warming, will lead to a complete loss of the permafrost. Depending on local hydrological conditions this may in turn lead to a wetting or drying of the environment with subsequent implications for greenhouse gas fluxes. Overall, the complex interactions between processes contributing to feedbacks, variability over time and space in these processes, and insufficient data have generated considerable uncertainties in estimating the net effects of climate change on terrestrial feedbacks to the climate system. This uncertainty applies to magnitude, and even direction of some of the feedbacks.  相似文献   

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A global three-dimensional (3D) transport–dispersion model was used to simulate Krypton-85 (85Kr) background concentrations at five sampling locations along the US east coast during 1982–1983. The samplers were established to monitor the 85Kr plume downwind of the Savannah river plant (SRP), a nuclear fuel reprocessing facility. The samplers were located 300–1000 km downwind of the SRP. In the original analyses of the measurements, a constant background concentration, representing an upper-limit and different for each sampling station, was subtracted from the measurements to obtain the part of the measurement representing the SRP plume. The use of a 3D global model, which includes all major 85Kr sources worldwide, was able to reproduce the day-to-day concentration background variations at the sampling locations with correlation coefficients of 0.36–0.46. These 3D model background predictions, without including the nearby SRP source, were then subtracted from the measured concentrations at each sampler, the result representing the portion of the measurement that can be attributed to emissions from the SRP. The revised plume estimates were a factor of 1.3–2.4 times higher than from the old method using a constant background subtraction. The greatest differences in the SRP plume estimates occurred at the most distant sampling stations.  相似文献   

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Environmental Science and Pollution Research - Mangrove crabs are ecosystem engineers through their bioturbation activity. On Mayotte Island, the abundance of Neosarmatium africanum decreased in...  相似文献   

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Environmental Science and Pollution Research - Hydrogen and oxygen stable isotopes (δ2H and δ18O) in precipitation were analysed from June 2018 to May 2020 in Ningbo and were influenced...  相似文献   

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Al, V, Mn, Fe, Cu, As, Cd, Ba, Pb, Bi and U were determined in a continuous series of 46 snow samples from a 2.3-m snow pit, covering the time period from austral spring 1998 to summer 2002, at a site on the east side of the Lambert Glacier basin in East Antarctica. Concentrations are very low for all metals and differ by orders of magnitude from one metal to another, with the mean concentrations ranging from 0.028 pg g−1 for Bi to 165 pg g−1 for Al. It is estimated that anthropogenic contributions are dominant for Cu, Pb and probably As, in the snow in our study area while the natural contributions from rock and soil dust, sea-salt spray and volcanic emissions account for most of the measured concentrations of the other metals. Our snow profiles show pronounced seasonal variations for Mn, As, Ba, Pb and Bi throughout the year, but a very different situation is observed between different metals. These observations suggest that heavy metals determined in our samples are controlled by different transport and deposition mechanisms related to physical and chemical alterations in the properties and sources of aerosol.  相似文献   

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Winter climate and snow cover are the important drivers of plant community development in polar regions. However, the impacts of changing winter climate and associated changes in snow regime have received much less attention than changes during summer. Here, we synthesize the results from studies on the impacts of extreme winter weather events on polar heathland and lichen communities. Dwarf shrubs, mosses and soil arthropods were negatively impacted by extreme warming events while lichens showed variable responses to changes in extreme winter weather events. Snow mould formation underneath the snow may contribute to spatial heterogeneity in plant growth, arthropod communities and carbon cycling. Winter snow cover and depth will drive the reported impacts of winter climate change and add to spatial patterns in vegetation heterogeneity. The challenges ahead lie in obtaining better predictions on the snow patterns across the landscape and how these will be altered due to winter climate change.  相似文献   

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Previous studies have shown the high sorption affinity of polycyclic aromatic hydrocarbons by cork. The aim of the present work is to go further by investigating the sorption mechanism of polycyclic aromatic hydrocarbons (exemplified by phenanthrene) on cork and the availability of the chemical components (i.e. lignin, suberin, holocellulose and extractives) to retain phenanthrene.Two approaches were integrated to reach this objective: (1) statistical multivariate analysis to obtain correlations between the sorption capacity, measured as Koc, and the sorbent properties (i.e. polarity, acidic functional groups, %dichloromethane extractives, %ethanol and water extractives, %suberin, %lignin and %holocellulose) and (2) modeling calculations to obtain information on interaction at the molecular level.The statistical multivariate analysis demonstrated a strong and positive correlation between Koc and the lignin content as well as negative correlations between Koc and the phenolic groups and %dichloromethane extractives contents. The modeling study showed that the lignin–phenanthrene interaction is mostly hydrophobic in nature being largely determined by the π-stacking interaction between the aromatic groups of the interacting partners. This result justifies the observed correlations as dichloromethane extractives, being hydrophobic, compete with phenanthrene adsorption, whereas phenolic groups, as well as negatively charged groups, enhance the hydrophilic character of the sorbent surface, thus hindering the adsorption of phenanthrene.  相似文献   

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Cholera epidemics have a recorded history in the eastern Africa region dating to 1836. Cholera is now endemic in the Lake Victoria basin, a region with one of the poorest and fastest growing populations in the world. Analyses of precipitation, temperatures, and hydrological characteristics of selected stations in the Lake Victoria basin show that cholera epidemics are closely associated with El Ni?o years. Similarly, sustained temperatures high above normal (T(max)) in two consecutive seasons, followed by a slight cooling in the second season, trigger an outbreak of a cholera epidemic. The health and socioeconomic systems that the lake basin communities rely upon are not robust enough to cope with cholera outbreaks, thus rendering them vulnerable to the impact of climate variability and change. Collectively, this report argues that communities living around the Lake Victoria basin are vulnerable to climate-induced cholera that is aggravated by the low socioeconomic status and lack of an adequate health care system. In assessing the communities' adaptive capacity, the report concludes that persistent levels of poverty have made these communities vulnerable to cholera epidemics.  相似文献   

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Environmental Science and Pollution Research - Colorectal carcinoma (CRC) is the second most common cancer diagnosed in Algeria. The incidence and the mortality rate of CRC have increased so that...  相似文献   

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The objective of this study was to quantify 2,4-D (2,4-dichlorophenoxyacetic acid) mineralization in soil profiles characteristic of hummocky, calcareous-soil landscapes in western Canada. Twenty-five soil cores (8 cm inner diameter, 50 to 125 cm length) were collected along a 360 m transect running west to east in an agricultural field and then segmented by soil-landscape position (upper slopes, mid slopes, lower slopes and depressions) and soil horizon (A, B, and C horizons). In the A horizon, 2,4-D mineralization commenced instantaneously and the mineralization rate followed first-order kinetics. In both the B and C horizons, 2,4-D mineralization only commenced after a lag period of typically 5 to 7 days and the mineralization rate was biphasic. In the A horizon, 2,4-D mineralization parameters including the first-order mineralization rate constant (k(1)), the growth-linked mineralization rate constant (k(2)) and total 2,4-D mineralization at the end of the experiment at 56 days, were most strongly correlated to parameters describing 2,4-D sorption by soil, but were also adequately correlated to soil organic carbon content, soil pH, and carbonate content. In both B and C horizons, there was no significant correlation between 2,4-D mineralization and 2,4-D sorption parameters, and the correlation between soil properties and 2,4-D mineralization parameters was very poor. The k(1) significantly decreased in sequence of A horizon (0.113% day(-1)) > B horizon (0.024% day(-1)) = C horizon (0.026% day(-1)) and in each soil horizon was greater than k(2). Total 2,4-D mineralization at 56 days also significantly decreased in sequence of A horizon (42%) > B horizon (31%) = C horizon (27%). In the A horizon, slope position had little influence on k(1) or k(2), except that k(1) was significantly greater in upper slopes (0.170% day(-1)) than in lower slopes (0.080% day(-1)). Neither k(1) nor k(2) was significantly influenced by slope position in the B or C horizons. Total 2,4-D mineralization at 56 days was not influenced by slope positions in any horizon. Our results suggest that, when predicting 2,4-D transport at the field scale, pesticide fate models should consider the strong differences in 2,4-D mineralization between surface and subsurface horizons. This suggests that 2,4-D mineralization is best predicted using a model that has the ability to describe a range of non-linear mineralization curves. We also conclude that the horizontal variations in 2,4-D mineralization at the field scale will be difficult to consider in predictions of 2,4-D transport at the field scale because, within each horizon, 2,4-D mineralization was highly variable across the twenty-five soil cores, and this variability was poorly correlated to soil properties or soil-landscape position.  相似文献   

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The objective of this study was to quantify 2,4-D (2,4-dichlorophenoxyacetic acid) mineralization in soil profiles characteristic of hummocky, calcareous-soil landscapes in western Canada. Twenty-five soil cores (8 cm inner diameter, 50 to 125 cm length) were collected along a 360 m transect running west to east in an agricultural field and then segmented by soil-landscape position (upper slopes, mid slopes, lower slopes and depressions) and soil horizon (A, B, and C horizons). In the A horizon, 2,4-D mineralization commenced instantaneously and the mineralization rate followed first-order kinetics. In both the B and C horizons, 2,4-D mineralization only commenced after a lag period of typically 5 to 7 days and the mineralization rate was biphasic. In the A horizon, 2,4-D mineralization parameters including the first-order mineralization rate constant (k 1), the growth-linked mineralization rate constant (k 2) and total 2,4-D mineralization at the end of the experiment at 56 days, were most strongly correlated to parameters describing 2,4-D sorption by soil, but were also adequately correlated to soil organic carbon content, soil pH, and carbonate content. In both B and C horizons, there was no significant correlation between 2,4-D mineralization and 2,4-D sorption parameters, and the correlation between soil properties and 2,4-D mineralization parameters was very poor. The k 1 significantly decreased in sequence of A horizon (0.113% day?1) > B horizon (0.024% day?1) = C horizon (0.026% day?1) and in each soil horizon was greater than k 2. Total 2,4-D mineralization at 56 days also significantly decreased in sequence of A horizon (42%) > B horizon (31%) = C horizon (27%). In the A horizon, slope position had little influence on k 1 or k 2, except that k 1 was significantly greater in upper slopes (0.170% day?1) than in lower slopes (0.080% day?1). Neither k 1 nor k 2 was significantly influenced by slope position in the B or C horizons. Total 2,4-D mineralization at 56 days was not influenced by slope positions in any horizon. Our results suggest that, when predicting 2,4-D transport at the field scale, pesticide fate models should consider the strong differences in 2,4-D mineralization between surface and subsurface horizons. This suggests that 2,4-D mineralization is best predicted using a model that has the ability to describe a range of non-linear mineralization curves. We also conclude that the horizontal variations in 2,4-D mineralization at the field scale will be difficult to consider in predictions of 2,4-D transport at the field scale because, within each horizon, 2,4-D mineralization was highly variable across the twenty-five soil cores, and this variability was poorly correlated to soil properties or soil-landscape position.  相似文献   

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Although sustainability and ethics are of increasing public importance, little research has been conducted to reveal its association with fish consumer behavior. Cross-sectional data were collected through a postal self-administered survey (June 2005) from a sample of 381 Flemish women aged 20-50 years. Consumers attach high perceived importance to sustainability and ethics related to fish. However, this perceived importance is neither correlated with fish consumption frequency nor with general attitude toward eating fish. Refusing to eat wild fish is grounded in sustainability and ethical concerns, whereas the decision not to eat farmed fish is associated with a lower expected intrinsic quality rather than shaped by importance attached to sustainability and ethical issues.  相似文献   

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A new predictive toxicokinetics model was developed to estimate subacute toxicity (target organs, severity, etc.) of non-congeneric industrial chemicals, where the chemical structures and physico-chemical properties are only available. Thus, a physiological pharmacokinetics model, which consists of blood, liver, kidney (these were experimentally found as major toxicological targets), muscle and fat compartments , was established to simulate the chemical concentrations in organs/tissues with pharmacokinetic parameters by means of Runge-Kutta-Gill algorithm. The pliarmacokinetic parameters, i.e. absorption rate, absorption ratio, hepatic extraction ratio of metabolism and renal clearance were calculated by using separately established Quantitative Structure-Pharmacokinetics Relationship equations. The developed predictive model was then applied to simulations of 43 non-congeneric industrial chemicals. The chemical concentrations in organs/tissues after single oral administration were simulated, and their maximum concentrations (Cmax's) and area tinder the concentration-time curves (AUC's) were calculated.Fast Inverse Laplace Transform was newly applied for the purpose of simulation of 28-day repeated dose toxicity.Simulated concentrations of 28 days repeated dose were, however, found to be the same as those of simple repetitions of a single administration per day because of the short half-lives of non-congeneric industrial chemicals.A comparison of subacute toxicity data with Cmax's and AUC's in a single dose scenario suggested that the organs/tissues with relatively high concentrations of tested chemical substances were the most sensitive targets within a chemical.Chemical concentrations in liver, for instance, were correlated with the severity of hepatotoxicity among the chemicals. It was also suggested that to improve and widen the present approach, data of metabolite and reactivity of non-congeneric industrial chemicals to organs/tissues, receptors, etc. should be incorporated into the model.  相似文献   

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