[Objective] The aim was to study the effect of site factor on plant community characteristic in closed watershed in loess hilly and gully region.[Method] Based on the investigation of vegetation in the closed watershe...[Objective] The aim was to study the effect of site factor on plant community characteristic in closed watershed in loess hilly and gully region.[Method] Based on the investigation of vegetation in the closed watershed of Wuqi County in Shaanxi Province,the difference of plant community characteristic and species diversity under various site types was researched in our paper.[Result] In the investigation area,xerophytic herb was the main community,with sole species composition and simple community structure.Zonal vegetations were Artemisia sacrorum and Artemisia giraldii community;for plant diversity,the order of diversity index was ridge topgully bottomridge slopegully slope in various landform positions and semi-shady slopeshady slopesemi-sunny slopesunny slope in various slope aspects;with the increase of gradient,the diversity index of sunny slope changed with ＂S＂ type,and it reached maximum value at 37°.[Conclusion] Our study could provide theoretical foundation for vegetative restoration in loess hilly and gully region.展开更多
The structure and dynamic succession law of natural secondary forest after severe fire interference in recent 20 years were studied by adopting the method of deducing time series from the spatial sequence of vegetatio...The structure and dynamic succession law of natural secondary forest after severe fire interference in recent 20 years were studied by adopting the method of deducing time series from the spatial sequence of vegetation in Heihe region, Heilongjiang, China. Two typical and widely distributed forest types in the study area, namely forest type A and forest type B, were selected as study subjects. Forest type A is pure broadleaf forest or broadleaf mixed forest mainly composing of superior Betula platyphylla and Populus davidiana in the area with gradient 〈25°, while forest type B is pure forest or mixed forest composing of superior Quercus mongolica and Betula davurica in the area with gradient 〉25°. Species richness, vegetation coverage, important value, and similarity index of commtmity in different layers （Herb, shrub, small tree, and arbor layers） were investigated and analyzed for the two typical forests. The results show that after fire interference, the species richness and coverage in each layer in forest type A were higher than that in forest type B. Both for forest type A and B, with elapse of post-fire years, the species richness and coverage of herbs and shrubs showed a decline tendency, while those of arbor layer present a rising tendency. Through comparison of the important values of species in each layer and analysis of community structure changes, the dynamic process of post-fire vegetation succession for forest type A and B was separately determined. Post-fire 80 years＇ succession tendency of forest type A is B. platyphylla and Larix gmelinii mixed forest. Its shrub layer is mainly composed of Corylus heterophylla and Vaccinium uliginosum, and herb layer is dominated by Carex tristachya, Athyrium multidentatum, and Pyrola incarnate; whereas, the post-fire 80 years＇ succession of forest type B is Q. mongolica and B. davurica mixed forest. Its shrub layer is mainly composed of lespedeza bicolar and corylus heterophylla and herb layer is dominated by Carex tristachya, Asparagus densiflorus, and Hemerocallis minor.展开更多
基金Supported by Forestry Key Technology R&D Program in the 11th Five year Plan of China(2006BAD03A0302)~~
文摘[Objective] The aim was to study the effect of site factor on plant community characteristic in closed watershed in loess hilly and gully region.[Method] Based on the investigation of vegetation in the closed watershed of Wuqi County in Shaanxi Province,the difference of plant community characteristic and species diversity under various site types was researched in our paper.[Result] In the investigation area,xerophytic herb was the main community,with sole species composition and simple community structure.Zonal vegetations were Artemisia sacrorum and Artemisia giraldii community;for plant diversity,the order of diversity index was ridge topgully bottomridge slopegully slope in various landform positions and semi-shady slopeshady slopesemi-sunny slopesunny slope in various slope aspects;with the increase of gradient,the diversity index of sunny slope changed with ＂S＂ type,and it reached maximum value at 37°.[Conclusion] Our study could provide theoretical foundation for vegetative restoration in loess hilly and gully region.
文摘The structure and dynamic succession law of natural secondary forest after severe fire interference in recent 20 years were studied by adopting the method of deducing time series from the spatial sequence of vegetation in Heihe region, Heilongjiang, China. Two typical and widely distributed forest types in the study area, namely forest type A and forest type B, were selected as study subjects. Forest type A is pure broadleaf forest or broadleaf mixed forest mainly composing of superior Betula platyphylla and Populus davidiana in the area with gradient 〈25°, while forest type B is pure forest or mixed forest composing of superior Quercus mongolica and Betula davurica in the area with gradient 〉25°. Species richness, vegetation coverage, important value, and similarity index of commtmity in different layers （Herb, shrub, small tree, and arbor layers） were investigated and analyzed for the two typical forests. The results show that after fire interference, the species richness and coverage in each layer in forest type A were higher than that in forest type B. Both for forest type A and B, with elapse of post-fire years, the species richness and coverage of herbs and shrubs showed a decline tendency, while those of arbor layer present a rising tendency. Through comparison of the important values of species in each layer and analysis of community structure changes, the dynamic process of post-fire vegetation succession for forest type A and B was separately determined. Post-fire 80 years＇ succession tendency of forest type A is B. platyphylla and Larix gmelinii mixed forest. Its shrub layer is mainly composed of Corylus heterophylla and Vaccinium uliginosum, and herb layer is dominated by Carex tristachya, Athyrium multidentatum, and Pyrola incarnate; whereas, the post-fire 80 years＇ succession of forest type B is Q. mongolica and B. davurica mixed forest. Its shrub layer is mainly composed of lespedeza bicolar and corylus heterophylla and herb layer is dominated by Carex tristachya, Asparagus densiflorus, and Hemerocallis minor.
