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151.
Neil C. Hutten Gerald F. Gifford 《Journal of the American Water Resources Association》1988,24(1):175-181
ABSTRACT: Rainfall simulator studies were conducted during 1982 and 1983 on agricultural and native rangeland soils of the same soil series in northern Utah. Results indicate that the same soil series mapped at different locations on agricultural land will have similar 10, 20, and 30 minute infiltration rates and similar interrill erosion rates. Seasonal differences in infiltration and erosion rates were significant. Comparisons between agricultural and native soils were complicated by three-way statistical interactions. Seasonal variations in both infiltration rates and erosion rates were greatest on agricultural soils. Of four soil series on native rangeland, only one showed significant seasonal variation in infiltration rates, while erosion rates were similar across all seasons for all soil series. Soil and cover factors important in predicting infiltration and erosion were identified. 相似文献
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Ayesha I. T. Tulloch Micha V. Jackson Elisa Bayraktarov Alexander R. Carey Diego F. Correa-Gomez Michael Driessen Ian C. Gynther Mel Hardie Katherine Moseby Liana Joseph Harriet Preece Andrés Felipe Suarez-Castro Stephanie Stuart John C. Z. Woinarski Hugh P. Possingham 《Conservation biology》2023,37(2):e14032
Monitoring is critical to assess management effectiveness, but broadscale systematic assessments of monitoring to evaluate and improve recovery efforts are lacking. We compiled 1808 time series from 71 threatened and near-threatened terrestrial and volant mammal species and subspecies in Australia (48% of all threatened mammal taxa) to compare relative trends of populations subject to different management strategies. We adapted the Living Planet Index to develop the Threatened Species Index for Australian Mammals and track aggregate trends for all sampled threatened mammal populations and for small (<35 g), medium (35–5500 g), and large mammals (>5500 g) from 2000 to 2017. Unmanaged populations (42 taxa) declined by 63% on average; unmanaged small mammals exhibited the greatest declines (96%). Populations of 17 taxa in havens (islands and fenced areas that excluded or eliminated introduced red foxes [Vulpes vulpes] and domestic cats [Felis catus]) increased by 680%. Outside havens, populations undergoing sustained predator baiting initially declined by 75% but subsequently increased to 47% of their abundance in 2000. At sites where predators were not excluded or baited but other actions (e.g., fire management, introduced herbivore control) occurred, populations of small and medium mammals declined faster, but large mammals declined more slowly, than unmanaged populations. Only 13% of taxa had data for both unmanaged and managed populations; index comparisons for this subset showed that taxa with populations increasing inside havens declined outside havens but taxa with populations subject to predator baiting outside havens declined more slowly than populations with no management and then increased, whereas unmanaged populations continued to decline. More comprehensive and improved monitoring (particularly encompassing poorly represented management actions and taxonomic groups like bats and small mammals) is required to understand whether and where management has worked. Improved implementation of management for threats other than predation is critical to recover Australia's threatened mammals. 相似文献
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研究总结近年来我国静脉产业园的发展现状,并分别从定位规划、市场环境、政策法规、园区管理、公众意识、技术创新和人才培养等方面,对我国静脉产业园区建设过程中存在的问题进行了分析。在此基础上,提出了完善我国静脉产业园区建设的一系列建议和措施。 相似文献
157.
鞍山大气中有机氯农药的污染特征研究 总被引:2,自引:0,他引:2
布设鞍钢工业区6个点位,周边2个点位,居民区2个点位和千山对照点等11个点位,分别在采暖期和非采暖期测定大气中有机氯农药的含量,掌握了鞍山市大气中有机氯农药空间和时间变化趋势。全年有机氯农药各组分和ΣOPC浓度最高的功能区均为工业区周边,最低的功能区是千山对照点,六六六、滴滴涕和ΣOPC浓度变化趋势为工业区周边工业区居住区千山对照点,全市各功能区采暖期有机氯农药各组分和ΣOPC总浓度均高于非采暖期。 相似文献
158.
生态资产概念、特点与研究趋向 总被引:7,自引:0,他引:7
针对目前研究现状中存在的问题,对生态资产中易混淆的相关概念进行了初步分析和界定;在阐述生态资产概念、特点的前提下,指出生态资产研究应在目前已有的静态生态资产研究的基础上,以动态和开放的视角开展生态资产耗损、生态资产转移等研究;初步构建了生态资产研究体系和应用框架,探索了生态资产研究趋向,提出生态资产研究应与区域经济社会发展密切联系,在区域生态环境与经济社会协调发展中实现其价值. 相似文献
159.
Time series of abundance estimates are commonly used for analyses of population trends and possible shifts in growth rate.
We investigate if trends in age composition can be used as an alternative to abundance estimates for detection of decelerated
population growth. Both methods were tested under two forms of density dependence and different levels of environmental variation
in simulated time series of growth in Baltic gray seals. Under logistic growth, decelerating growth could be statistically
confirmed after 16 years based on population counts and 14 years based on age composition. When density dependence sets in
first at larger population sizes, the age composition method performed dramatically better than population counts, and a decline
could be detected after 4 years (versus 10 years). Consequently, age composition analysis provides a complementary method
to detect density dependence, particularly in populations where density dependence sets in late. 相似文献
160.