Research into landscape history makes it possible to follow landscape changes in the past and support landscape management, conservation and restoration programs. Floodplain habitats are lost, isolated and fragmented on account of land use. Nowadays, these habitats are threatened by modifications in the natural water regime, as well as agricultural and forestry practices. Floodplains have great importance because they provide a transition between aquatic habitats and terrestrial biotopes. Our analysis of aerial photographs and topographical maps revealed that the major predicted changes in the study area are related to agricultural abandonment and afforestation. The comparison of land cover maps from 1784 to 2005 showed intensification of agriculture with land cover conversions from arable land and orchards to grasslands, marshes and woodlands. The land use types that are mostly responsible for the fragmentation of the landscape are arable land, economic plantations and orchards. We found that fragmentation was greater after 1956. This was caused by socioeconomic changes and showed that the habitats of floodplains have changed intensively during the last 200 years. Knowledge of this last 200 years of history contributes to a more careful and wiser management of the region through biodiversity protection and environmental development. 相似文献
Understanding how cities can transform organic waste into a valuable resource is critical to urban sustainability. The capture and recycling of phosphorus (P), and other essential nutrients, from human excreta is particularly important as an alternative organic fertilizer source for agriculture. However, the complex set of socio-environmental factors influencing urban human excreta management is not yet sufficiently integrated into sustainable P research. Here, we synthesize information about the pathways P can take through urban sanitation systems along with barriers and facilitators to P recycling across cities. We examine five case study cities by using a sanitation chains approach: Accra, Ghana; Buenos Aires, Argentina; Beijing, China; Baltimore, USA; and London, England. Our cross-city comparison shows that London and Baltimore recycle a larger percentage of P from human excreta back to agricultural lands than other cities, and that there is a large diversity in socio-environmental factors that affect the patterns of recycling observed across cities. Our research highlights conditions that may be “necessary but not sufficient” for P recycling, including access to capital resources. Path dependencies of large sanitation infrastructure investments in the Global North contrast with rapidly urbanizing cities in the Global South, which present opportunities for alternative sanitation development pathways. Understanding such city-specific social and environmental barriers to P recycling options could help address multiple interacting societal objectives related to sanitation and provide options for satisfying global agricultural nutrient demand.
Forest fire regimes are sensitive to alterations of climate, fuel load, and ignition sources. We investigated the impact of human activities and climate on fire occurrence in a dry continental valley of the Swiss Alps (Valais) by relating fire occurrence to population and road density, biomass removal by livestock grazing and wood harvest, temperature and precipitation in two distinct periods (1904–1955 and 1956–2006) using generalized additive modeling. This study provides evidence for the role played by humans and temperature in shaping fire occurrence. The existence of ignition sources promotes fire occurrence to a certain extent only; for example, high road density tends to be related to fewer fires. Changes in forest uses within the study region seem to be particularly important. Fire occurrence appears to have been negatively associated with livestock pasturing in the forest and wood harvesting, in particular during the period 1904–1955. This study illustrates consistently how fire occurrence has been influenced by land use and socioeconomic conditions. It also suggests that there is no straightforward linear relationship between human factors and fire occurrence. 相似文献
Annually since 1989, biannually since 1994, the environs (approximately 50 km2) of the Swiss nuclear facilities are surveyed (by helicopters) flying the same survey lines. The equipment and the data processing software used for these surveys were built and developed at the Institute of Geophysics, ETH Zurich. For mapping of man-made radiation at or around nuclear facility sites a pixel representation and the MMGC (man-made gross count) ratio is used. So far no artificial radioactivity that could not be explained by the Chernobyl event (1986) or by earlier nuclear weapon tests was detected outside the fenced sites of the nuclear facilities. 相似文献
Arctic residents, whose diets comprise a large proportion of traditional terrestrial and freshwater foodstuffs, have received the highest radiation exposures to artificial radionuclides in the Arctic. Doses to members of both the average population and selected indigenous population groups in the Arctic depend on the rates of consumption of locally-derived terrestrial and freshwater foodstuffs, including reindeer/caribou meat, freshwater fish, goat cheese, berries, mushrooms and lamb. The vulnerability of arctic populations, especially indigenous peoples, to radiocaesium deposition is much greater than for temperate populations due to the importance of terrestrial, semi-natural exposure pathways where there is high radiocaesium transfer and a long ecological half-life for this radionuclide. In contrast, arctic residents with diets largely comprising marine foodstuffs have received comparatively low radiation exposures because of the lower levels of contamination of marine organisms. Using arctic-specific information, the predicted collective dose is five times higher than that estimated by UNSCEAR for temperate areas. The greatest threats to human health and the environment posed by human and industrial activities in the Arctic are associated with the potential for accidents in the civilian and military nuclear sectors. Of most concern are the consequences of potential accidents in nuclear power plant reactors, during the handling and storage of nuclear weapons, in the decommissioning of nuclear submarines and in the disposal of spent nuclear fuel from vessels. It is important to foster a close association between risk assessment and practical programmes for the purposes of improving monitoring, formulating response strategies and implementing action plans. 相似文献
Delivering access to sufficient food, energy and water resources to ensure human wellbeing is a major concern for governments worldwide. However, it is crucial to account for the ‘nexus’ of interactions between these natural resources and the consequent implications for human wellbeing. The private sector has a critical role in driving positive change towards more sustainable nexus management and could reap considerable benefits from collaboration with researchers to devise solutions to some of the foremost sustainability challenges of today. Yet opportunities are missed because the private sector is rarely involved in the formulation of deliverable research priorities. We convened senior research scientists and influential business leaders to collaboratively identify the top forty questions that, if answered, would best help companies understand and manage their food-energy-water-environment nexus dependencies and impacts. Codification of the top order nexus themes highlighted research priorities around development of pragmatic yet credible tools that allow businesses to incorporate nexus interactions into their decision-making; demonstration of the business case for more sustainable nexus management; identification of the most effective levers for behaviour change; and understanding incentives or circumstances that allow individuals and businesses to take a leadership stance. Greater investment in the complex but productive relations between the private sector and research community will create deeper and more meaningful collaboration and cooperation. 相似文献
The BIOMASS Theme 1 project has developed a methodology for the logical and defensible construction of 'assessment biospheres': mathematical representations of biospheres used in the total system performance assessment of radioactive waste disposal. The BIOMASS Methodology provides a systematic approach to decision making, including decisions on how to address biosphere change. The BIOMASS Methodology was developed through consultation and collaboration with many relevant organisations, including regulators, operators and a variety of independent experts. It has been developed to be practical and to be consistent with recommendations from ICRP and IAEA on radiation protection in the context of the disposal of long-lived solid radioactive wastes. The five main steps in the methodology are described in this paper. The importance of a clear assessment context, to clarify intentions and to support a coherent biosphere assessment process within an overall repository performance assessment, is strongly emphasised. A well described assessment context is an important tool for ensuring consistency across the performance assessment as a whole. The use of interaction matrices has been found to be helpful in clarifying the interactions between different habitats within the biosphere system and the significant radionuclide transfer pathways within the biosphere system. Matrices also provide a useful means of checking for consistency. 相似文献
Nonylphenol is a toxic xenobiotic compound classified as an endocrine disrupter capable of interfering with the hormonal system of numerous organisms. It originates principally from the degradation of nonylphenol ethoxylates which are widely used as industrial surfactants. Nonylphenol ethoxylates reach sewage treatment works in substantial quantities where they biodegrade into several by-products including nonylphenol. Due to its physical-chemical characteristics, such as low solubility and high hydrophobicity, nonylphenol accumulates in environmental compartments that are characterised by high organic content, typically sewage sludge and river sediments, where it persists. The occurrence of nonylphenol in the environment is clearly correlated with anthropogenic activities such as wastewater treatment, landfilling and sewage sludge recycling. Nonylphenol is found often in matrices such as sewage sludge, effluents from sewage treatment works, river water and sediments, soil and groundwater. The impacts of nonylphenol in the environment include feminization of aquatic organisms, decrease in male fertility and the survival of juveniles at concentrations as low as 8.2 mug/l. Due to the harmful effects of the degradation products of nonylphenol ethoxylates in the environment, the use and production of such compounds have been banned in EU countries and strictly monitored in many other countries such as Canada and Japan. Although it has been shown that the concentration of nonylphenol in the environment is decreasing, it is still found at concentrations of 4.1 mug/l in river waters and 1 mg/kg in sediments. Nonylphenol has been referred to in the list of priority substances in the Water Frame Directive and in the 3rd draft Working Document on Sludge of the EU. Consequently there is currently a concern within some industries about the possibility of future regulations that may impose the removal of trace contaminants from contaminated effluents. The significance of upgrading sewage treatment works with advanced treatment technologies for removal of trace contaminants is discussed. 相似文献