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661.
The population of foxes in the central regions of Yakutia has grown by a factor of four to five during the period from 2000 to 2011–2012, following an increase in the abundance of voles from the genus Microtus. A total of 130 carcasses of foxes taken in 2007–2012 have been examined. Age- and sex-related variation in morphological features has been described. The demographic structure of the population has been studied by estimating animal age from annual layers in the recording structures. Changes in female fertility and involvement in reproduction depending on age and feeding conditions have been analyzed. Changes in the composition of fox diet caused by long-term population depression in the mountain hare and their effect on the dynamics of fox abundance have been revealed. Age- and sex-related characteristics of the condition factor in foxes and sex-related differences in their dietary preferences have been demonstrated.  相似文献   
662.
Nematode communities in the rooted soil layer under the crowns of introduced tree species on Valaam Island (Republic of Karelia) have been studied by conventional nematological methods to evaluate their taxonomic diversity, population density, and eco-trophic structure. On the whole, 49 nematode genera have been recorded, with their total abundance varying from 1209 to 2548 ind./100 g soil. The abundance and proportion of plant parasites in the soil nematode assemblage have proved to be higher under introduced trees, compared to natural forest biocenoses.  相似文献   
663.
Fire history within the northern larch forests of Central Siberia was studied (65 + °N). Fires within this area are predominantly caused by lightning strikes rather than human activity. Mean fire return intervals (FRIs) were found to be 112 ± 49 years (based on firescars) and 106 ± 36 years (based on firescars and tree natality dates). FRIs were increased with latitude increase and observed to be about 80 years at 64°N, about 200 years near the Arctic Circle and about 300 years nearby the northern range limit of larch stands (~71° + N). Northward FRIs increase correlated with incoming solar radiation (r = ?0.95). Post-Little Ice Age (LIA) warming (after 1850) caused approximately a doubling of fire events (in comparison with a similar period during LIA). The data obtained support a hypothesis of climate-induced fire frequency increase.  相似文献   
664.
Climate change generally requires species to migrate northward or to higher elevation to maintain constant climate conditions, but migration requirement and migration capacity of individual species can vary greatly. Individual populations of species occupy different positions in the landscape that determine their required range shift to maintain similar climate, and likewise the migration capacity depends on habitat connectivity. Here, we demonstrate an approach to quantifying species vulnerabilities to climate change for 419 rare vascular plants in Alberta, Canada, based on a multivariate velocity of climate change metric, local habitat fragmentation, and migration capacity. Climate change velocities indicated that future migration requirements ranged from 1 to 5 km/year in topographically complex landscapes, such as the Alberta Foothills and Rocky Mountains. In contrast, migration requirements to maintain constant climate in relatively flat Boreal Plains, Parkland, and Grassland ranged from 4 to 8 km/year. Habitat fragmentation was also highest in these flat regions, particularly the Parkland Natural Region. Of the 419 rare vascular plants assessed, 36 were globally threatened (G1–G3 ranking). Three globally threatened species were ranked as extremely vulnerable and five species as highly vulnerable to the interactions among climate change velocity, habitat fragmentation, and migration capacity. Incorporating dispersal characteristics and habitat fragmentation with local patterns in climate change velocity improves the assessment of climate change threats to species and may be applied to guide monitoring efforts or conservation actions.  相似文献   
665.
Civic ecology practices, such as community gardening and citizen-led urban reforestation and wetland restoration, provide opportunities for social learning. Because social learning is an important component of community resilience, we suggest that civic ecology practices can be a strategy for responding to and mitigating environmental disturbances in an era threatened by climate change. Despite the links between civic ecology, social learning and community resilience, empirical research that systematically considers these connections is limited. This study addresses this gap by introducing ‘frames’ as an approach to considering social learning outcomes and process. More specifically, we provide a model for investigating the role civic ecology education programs play in shaping youths’ capacity to understand and respond to environmental disturbance. We used participant observation and cognitive mapping to assess social learning among three youth restoration programs working in the wake of Hurricane Sandy in New York, NY, and after the 2013 floods in Boulder, CO. In all three programs, youth demonstrated social learning and cognitive change by shifting their emphasis from the impacts of disturbance towards a solutions-based framing that focused on community, action, and mitigation. However, the depth of these changes was not uniform across all programs, suggesting that variations in program length, community context, social identity, and opportunities for self-defined action may shape overall impacts of programs and youth capacity for future action.  相似文献   
666.
Ecological science contributes to solving a broad range of environmental problems. However, lack of ecological literacy in practice often limits application of this knowledge. In this paper, we highlight a critical but often overlooked demand on ecological literacy: to enable professionals of various careers to apply scientific knowledge when faced with environmental problems. Current university courses on ecology often fail to persuade students that ecological science provides important tools for environmental problem solving. We propose problem-based learning to improve the understanding of ecological science and its usefulness for real-world environmental issues that professionals in careers as diverse as engineering, public health, architecture, social sciences, or management will address. Courses should set clear learning objectives for cognitive skills they expect students to acquire. Thus, professionals in different fields will be enabled to improve environmental decision-making processes and to participate effectively in multidisciplinary work groups charged with tackling environmental issues.  相似文献   
667.
Drought is a significant natural hazard that slowly evolves over time. Because of its character, drought is difficult to monitor and impacts are often poorly documented. Agriculture is one of the most sensitive sectors that are prone to drought. The objective of this research is to assess the impacts of drought on soybean production and revenue in Kentucky. Soybeans are one of Kentucky’s most important commodities. In this study, impacts of 1930–1931, 1940–1942, 1952–1955, 1987–1988, 1999–2000, and 2007 droughts were considered. It was found that over the recent years, up to 56 % of the revenue from soybeans was lost due to drought. During the first half of the twentieth century, revenue loss reached up to 77 %. This research is valuable to the general public as well as planners and policy makers. Proper documentation of impacts of past droughts will help identify drought vulnerabilities and results in better risk management and mitigation.  相似文献   
668.
生物滴滤塔净化挥发性有机废气动力学模型研究   总被引:2,自引:1,他引:1  
通过对生物滴滤塔净化VOCs废气过程的分析,建立了动力学模型,简化处理后得出了基于生物降解为一级反应动力学和零级反应动力学的污染物浓度沿填料层高度变化的方程,并通过实验数据对方程进行了验证,结果表明基于生物降解一级反应动力学的方程能较好地与实验数据吻合,但常数ξα/Q却随入口浓度Cgi的增大而升高。最后,采用实验数据回归出了ξα/Q随Cg变化的曲线。  相似文献   
669.
Journal of Material Cycles and Waste Management - Leather production is a technology that boosts the economy because of its versatility and durability. However, the wastes generated throughout the...  相似文献   
670.
Journal of Material Cycles and Waste Management - The daily use of facemask to prevent virus transmission increases the negative effect on the environment because of improper waste disposal. Due to...  相似文献   
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