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遥感技术在大面积天然草地估产和预报中的应用探讨 总被引:26,自引:0,他引:26
利用新疆北疆地区不同草地类型上观测的草地可食产量、环境与遥感资料等,使用3S技术进行了相关分析和遥感估产及预报,建立了地面光学和线性或非线性遥感估产及产量预报模型,在实际估产和产量预测中加以应用、检验,并给出了生态学解释。 相似文献
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GIMMS(Global Inventory Modeling and Mapping Studies) NDVI(Normalised Difference Vegetation Index) from 1982 to 2006 and MODIS(Moderate Resolution Imaging Spectroradiometer) NDVI from 2001 to 2010 were blended to extract the grass coverage and analyze its spatial pattern. The response of grass coverage to climatic variations at annual and monthly time scales was analyzed. Grass coverage distribution had increased from northwest to southeast across China. During 1982–2010, the mean nationwide grass coverage was 34% but exhibited apparent spatial heterogeneity, being the highest(61.4%) in slope grasslands and the lowest(17.1%) in desert grasslands. There was a slight increase of the grass coverage with a rate of 0.17% per year. Increase in slope grasslands coverage was as high as 0.27% per year, while in the plain grasslands and meadows the grass coverage increase was the lowest(being 0.11% per year and 0.1% per year, respectively). Across China, the grass coverage with extremely significant increase(P0.01) and significant increase(P0.05) accounted for 46.03% and 11% of the total grassland area, respectively, while those with extremely significant and significant decrease accounted for only 4.1% and 3.24%, respectively. At the annual time scale, there are no significant correlations between grass coverage and annual mean temperature and precipitation. However, the grass coverage was somewhat affected by temperature in alpine and sub-alpine grassland, alpine and sub-alpine meadow, slope grassland and meadow, while grass coverage in desert grassland and plain grassland was more affected by precipitation. At the monthly time-scale, there are significant correlations between grass coverage with both temperature and precipitation, indicating that the grass coverage is more affected by seasonal fluctuations of hydrothermal conditions. Additionally, there is one-month time lag-effect between grass coverage and climate factors for each grassland types. 相似文献
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准确掌握鱼类物种多样性及其资源时空分布规律是鱼类资源养护和利用的基本前提和重要基础。作者采用底拖网在蜈支洲岛毗邻海域进行年际(2020年8月和11月、2021年1月和4月)的渔业资源调查,共捕获鱼类174种,隶属2纲、12目、65科、123属,趋礁性鱼类物种数有较高的比重(35.6%)。常年种(宽条鹦天竺鲷(Ostorhiegnchus fasciatus)、准大头狗母鱼(Trachiocephalus myops)和少鳞䲢(Uranoscopus oligolepis))为主导该海域鱼类资源量季度变化的主要类群,但季节种(印度侧带小公鱼(Stolephorusindicus)、短鳄齿鱼(Champsodonsnyderi)和鹿斑仰口鲾(Secutor ruconius)等)也能在一定程度扰动由常年种鱼类主导的鱼类群落结构,从而使得群落结构呈季节性变化。除秋季外,其他3个季节的鱼类群落组成主要为幼鱼,表明毗邻海域的岛礁生境有聚集鱼类和保育幼鱼的重要作用。与该海域2019年的渔业资源调查数据比较,其鱼类组成丰富度与均匀度高度一致,鱼类群落未发生生态位交替失调现象,表明蜈支洲岛毗邻海域鱼类群落结构较为稳定且资源状况良好。本研究所获得的相关数据将有助于蜈支洲岛海洋牧场建设过程中的生态效果评估的工作开展。 相似文献
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