Ma Kehe forest region is one of the core areas in San Jiangyuan National Nature Reserve. A large number of shrub species distribute in the cold temperate coniferous forest, which have important influence on the succes...Ma Kehe forest region is one of the core areas in San Jiangyuan National Nature Reserve. A large number of shrub species distribute in the cold temperate coniferous forest, which have important influence on the succession and restoration of the cold temperate coniferous forest. A series of techniques including relative tests and calculation of the percentage of co-occurrence were used to analyze the interspecific association among 20 dominant shrub species in 40 plots in Ma Kehe forest region of San Jiangyuan National Nature Reserve. The results showed that most of interspecific association of dominant shrub species was significantly negative. Only 69 species pairs were of positive correlation among 190 dominant shrub species pairs, 113 species pairs were of negative correlation, 8 species pairs were of absolute independent correlation. So, only a few dominant shrub species had positive interspecific association, most of them had little opportunity to use the same resources and occupy similar niche in the same community due to their competitions in Ma Kehe forest region.展开更多
Slope aspect has significant effect on the development and distribution of montane forest, especially in arid and semiarid regions. This paper, using SPOT5 images and 1：5o,ooo DEM, digitally extracts and analyzes the...Slope aspect has significant effect on the development and distribution of montane forest, especially in arid and semiarid regions. This paper, using SPOT5 images and 1：5o,ooo DEM, digitally extracts and analyzes the spatial information of montane coniferous forest （mainly Qinghai spruce）, and thereby explores how the upper and lower limits and the altitudinal range of coniferous forest vary and how the area of coniferous forest is related with annual insolation with all aspects in the Helan Mountains. The results show that： 1） In the eastern flank, the lower limit of coniferous forest is between 1,6oo m and a,ooo m a.s.l., and the upper limit between 2,800 m and 3,ooo m a.s.1.; in the western flank, the lower limit of coniferous forest is between a,ooo m and 2,300 m a.s.l., and the upper limit between 9,80o m and 3,1oo m a.s.1.2） The altitudinal ranges of coniferous forest are 8o6-1,435 m, 438-1,14o m for eastern flank and western flank, respectively. 3） The area of coniferous forest takes on a normal distribution with aspect, and it has a close relationship with annual insolation. This distribution model developed in this paper quantitatively reveals the significant effect of slope aspect on the distribution of coniferous forest in arid and semi-arid land.展开更多
文摘Ma Kehe forest region is one of the core areas in San Jiangyuan National Nature Reserve. A large number of shrub species distribute in the cold temperate coniferous forest, which have important influence on the succession and restoration of the cold temperate coniferous forest. A series of techniques including relative tests and calculation of the percentage of co-occurrence were used to analyze the interspecific association among 20 dominant shrub species in 40 plots in Ma Kehe forest region of San Jiangyuan National Nature Reserve. The results showed that most of interspecific association of dominant shrub species was significantly negative. Only 69 species pairs were of positive correlation among 190 dominant shrub species pairs, 113 species pairs were of negative correlation, 8 species pairs were of absolute independent correlation. So, only a few dominant shrub species had positive interspecific association, most of them had little opportunity to use the same resources and occupy similar niche in the same community due to their competitions in Ma Kehe forest region.
基金supported by the Naional 973 project (2009CB421307) the National Natural Science Foundation of China (41030528 and 40971064)
文摘Slope aspect has significant effect on the development and distribution of montane forest, especially in arid and semiarid regions. This paper, using SPOT5 images and 1：5o,ooo DEM, digitally extracts and analyzes the spatial information of montane coniferous forest （mainly Qinghai spruce）, and thereby explores how the upper and lower limits and the altitudinal range of coniferous forest vary and how the area of coniferous forest is related with annual insolation with all aspects in the Helan Mountains. The results show that： 1） In the eastern flank, the lower limit of coniferous forest is between 1,6oo m and a,ooo m a.s.l., and the upper limit between 2,800 m and 3,ooo m a.s.1.; in the western flank, the lower limit of coniferous forest is between a,ooo m and 2,300 m a.s.l., and the upper limit between 9,80o m and 3,1oo m a.s.1.2） The altitudinal ranges of coniferous forest are 8o6-1,435 m, 438-1,14o m for eastern flank and western flank, respectively. 3） The area of coniferous forest takes on a normal distribution with aspect, and it has a close relationship with annual insolation. This distribution model developed in this paper quantitatively reveals the significant effect of slope aspect on the distribution of coniferous forest in arid and semi-arid land.
