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| Traits of water ecotypes and life-form spectrum of vegetation under canopy of Robinia pseudoacacia forests |
| Liu Jianghua1,2,Li Dengwu3,Liu Guobin1,3,Li Xiaoli1,2, Hou Xilu1,3 |
1.Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,712100,Yangling,Shaanxi;2.Graduate School of
Chinese Academy of Sciences,100039,Beijing;3.Northwest A&F University,712100,Yangling,Shaanxi: China |
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Abstract Robinia pseudoacacia is one of the main tree species for afforestation on Loess Plateau.To gian a better understanding of the impacts that Robinia pseudoacacia do to undergrowth,we investigated species components,water ecotypes and life-form spectrum of vegetation under Robinia pseudoacacia forest stands with different age in forest-steppe zone on Loess Plateau.We learned that,although Robinia pseudoacacia over-consumed soil water and soil tend to dry, vegetation changed from xeromorphic to mesophyte vegetation,and vegetation succession under Robinia pseudoacacia canopy had a similar process to natural succession on abandoned farmlands.From species components,it had no xeromorphic trend.Different from succession series on abandoned farmland,Bothriochloa ischaemum,as a constructive species in native plant communities,didn't become dominant species in all plots.Along with age growth,two distinct synusias emerged under Robinia pseudoacacia canopy.One was the Chamaephytes synusias dominated by vermuth suffruticose such as Artemisia gmelinii,and the other was the Hemicryptophytes synusias dominated by perennial gramineous hemicryptophyte such as Stipa bungeana.It is concluded that natural succession of undergrowth was not fundamentally changed by the growth of Robinia pseudoacacia.It was feasible to select Robinia pseudoacacia as a pioneer tree specie to restore vegetation in local region.
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Received: 01 June 2007
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