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中国东部南北样带森林生态系统WUE和NUE空间格局及驱动因子(英文) 总被引：4，自引：1，他引：3
From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China (NSTEC). Based on these samples, we studied the geographical distribution patterns of vegetable water use efficiency (WUE) and nitrogen use efficiency (NUE), and analyzed their relationship with environmental factors. The vegetable WUE and NUE were calculated through the measurement of foliar δ 13C and C/N of predominant species, respectively. The results showed: (1) vegetable WUE, ranging from 2.13 to 28.67 mg C g-1 H2O, increased linearly from south to north in the representative forest ecosystems along the NSTEC, while vegetable NUE showed an opposite trend, increasing from north to south, ranging from 12.92 to 29.60 g C g-1 N. (2) Vegetable WUE and NUE were dominantly driven by climate and significantly affected by soil nutrient factors. Based on multiple stepwise regression analysis, mean annual temperature, soil phosphorus concentration, and soil nitrogen concentration were responding for 75.5% of the variations of WUE (p<0.001). While, mean annual precipitation and soil phosphorus concentration could explain 65.7% of the change in vegetable NUE (p<0.001). Moreover, vegetable WUE and NUE would also be seriously influenced by atmospheric nitrogen deposition in nitrogen saturated ecosystems. (3) There was a significant trade-off relationship between vegetable WUE and NUE in the typical forest ecosystems along the NSTEC (p<0.001), indicating a balanced strategy for vegetation in resource utilization in natural forest ecosystems along the NSTEC. This study suggests that global change would impact the resource use efficiency of forest ecosystems. However, vegetation could adapt to those changes by increasing the use efficiency of shortage resource while decreasing the relatively ample one. But extreme impacts, such as heavy nitrogen deposition, would break this trade-off mechanism and give a dramatic disturbance to the ecosystem biogeochemical cycle. 相似文献
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房屋震害小区划,是指在一定小区域范围内,对房屋建筑遭受不同震害程度的划分,唐山地震后,我们使用航空象片房屋倒塌率判读法,进行了二次划分,得到了新的《唐山地震房屋灾害小区划图》。文中收集了七份现有的成果,经过分析对比,由文中所提新方法得到的结果,在真实性,精度和表达能力等方面,均优于其他成果。 相似文献
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为了在地震灾害调查中引进航空摄影测量和制图技术,唐山一九七六年地震后进行了一次广泛地试验。本文介绍了唐山地震后航空摄影测量和制图工作及取得的成果。并利用这些资料对房屋破坏、喷水冒沙等主要宏观震害现象进行了分析研究,得到了这次地震震害的一些特征。初步证实,在地震灾害调查中使用航空方法,是一项很有价值的新技术。 相似文献
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