千岛湖风化基岩消落带植被的垂直分布特征

【目的】研究自然植被在湖滨消落带的分布规律,为消落带植被修复与重建提供参考。【方法】在千岛湖区风化基岩消落带上采用固定样地调查方法,结合千岛湖水位涨落动态观察,通过物种重要值、聚类分析及其多样性,研究自然植被在海拔98.0~108.9 m的垂直分布特征。【结果】千岛湖水位基本上呈现1—3月为98~100 m的低水位、4—6月逐渐升高至104 m、7—9月为105~106 m的高水位、10—12月再逐渐回落至100 m低水位的年变化动态规律。风化基岩消落带植被的垂直分布与水位的季节性涨落或淹没时间有关,106.0~108.9 m区间为乔灌草植被带,乔木种类主要有木荷(Schima superba)、香樟(Cinnamomum camphora)等;104.0~105.9 m区间为灌草植被带,主要种类有苦竹(Pleioblastus amarus)、山莓(Rubus corchorifolius)等灌木和大狼杷草(Bidens frondosa)、鼠曲草(Pseudognaphalium affine)等草本;102.0~103.9 m区间为草本植被带,主要种类为上位灌草植被带出现的毛茛(Ranunculus japonicus)、酸模(Rumex acetosa)、泥胡菜(Hemisteptia lyrata)、狗牙根(Cynodon dactylon)、类芦(Neyraudia reynaudiana)、粉披苔草(Carex pruinosa)等草本,但盖度只有20%左右;98.0~101.9 m区间为无植被带。植物的多样性自上而下基本呈现上多下少的现象。【结论】千岛湖106.0~108.9 m乔灌草植被带、104.0~105.9 m灌草植被带自然植被的垂直分布和结构特征为消落带植被人工修复与重建提供了物种选择及其结构配置的重要依据;102.0~103.9 m草本植被带和98.0~101.9 m无植被带是千岛湖风化基岩消落带生态系统极度脆弱的区间带,也是植被修复与重建最难、最重要的区间带。

The characteristics of vertical vegetation distribution in hydro-fluctuation zone based on weathered bedrock in the Thousand Island Lake region

Objective] A comprehensive understanding of the distribution pattern of vegetation in a hydro-fluctuation zone could provide a strong basis for guiding the restoration and reconstruction of the plant community in this zone.Methods] We carried out detailed plant community surveys in the Thousand Island Lake,at several fixed sampling plots on weathered bedrock within the hydro-fluctuation zone.Based on the variation in water level,we analyzed the features of the vertical distribution of natural vegetation within the altitude range of 98.0-108.9 m,using indices of diversity,species importance values,and clustering analyses.Results] The water level showed a regular seasonal variation:it was low (98-100 m) from January to March,rose to 104 m during April-June,and reached its maximum (105-106 m)from July to September,followed by a rapid decrease to about 100 m from October to December.The vertical distribution pattern of vegetation in the fluctuation zone was associated with the seasonal variation in water level and flooding time.Tree-shrub-herbaceous vegetation was present in the altitude range from 106.0 to 108.9 m,with the dominant tree species being Schima superba and Cinnamomum camphora.Shrub-herbaceous vegetation existed in the hydro-fluctuation zone from 104.0 to 105.9 m,where Pleioblastus amarus and Rubus corchorifolius were the dominant shrubs and herbs mainly comprised Bidens frondosa and Pseudognaphalium affine.Only herbaceous vegetation,with coverage of approximately 20％,was observed in the low water level zone from 102.0 to 103.9 m,primarily constituted of herbaceous species that also appeared in shrub-herbaceous vegetation,including Ranunculus japonicus,Rumex acetosa,Hemisteptia lyrata,Cynodon dactylon,Neyraudia reynaudiana and Carex pruinosa.Vegetation was entirely absent within the altitude range of 98.0-101.9 m.The plant diversity therefore decreased with descending altitude.Conclusion] The characteristics and pattern of vertical distribution of vegetation on weathered bedrock in the hydro-fluctuation zone provides a species pool and potential species configuration for ecological restoration and reconstruction.In addition,the herbaceous vegetation and non-vegetation zones are extremely vulnerable in the hydro-fluctuation vegetation zone in the Thousand Island Lake,and thereby become the most difficult and important areas for ecological restoration and reconstruction.