井冈山山顶矮林乔木层优势种的生态位研究

对34个井冈山山顶矮林样地乔木层14个优势种的频度、重要值、Levins生态位宽度( Bi )和Morisita生态位重叠指数( Oik )进行了分析。结果表明：在井冈山山顶矮林乔木层的14个优势种中,鹿角杜鹃( Rhododendron latoucheae Franch.)、交让木( Daphniphyllum macropodum Miq.)、云锦杜鹃( Rhododendron fortunei Lindl.)、猴头杜鹃(Rhododendron simiarum Hance)和柃木(Eurya japonica Thunb.)的频度、重要值和Bi值均较高,其频度分别为0.59、0.53、0.38、0.38和0.35,重要值平均值分别为12.46%、24.63%、31.97%、38.03%和11.48%,Bi值分别为1.278、1.190、1.047、1.046和1.046；而甜槠也Castanopsis eyrei (Champ. ex Benth.) Tutch.页和野山楂(Crataegus cuneata Sieb. et Zucc.)的频度、重要值和Bi值基本上均较低,频度均为0.21,重要值分别为11.02%和5.95%,Bi值分别为0.781和0.654。14个优势种间的生态位重叠程度总体偏低,89.01%种对间的Oik值低于0.4。研究结果显示：井冈山山顶矮林乔木层优势种的生态位宽度与其重要值、频度、生物学特性和种间关系有关,且各优势种对共同资源的竞争较弱；总体来看,井冈山山顶矮林处于相对稳定阶段。

Study on niche of dominant species at arbor layer in montane elfin forest of Jinggangshan

Frequency, important value, Levins niche breadth ( Bi ) and Morisita niche overlap index ( Oik ) of 14 dominant species at arbor layer of 34 plots in montane elfin forest of Jinggangshan were analyzed. The results show that among 14 dominant species at arbor layer in montane elfin forest of Jinggangshan, frequency, important value and Bi value of Rhododendron latoucheae Franch., Daphniphyllum macropodum Miq., Rhododendron fortunei Lindl., Rhododendron simiarum Hance and Eurya japonica Thunb. all are higher, their frequency is 0. 59, 0. 53, 0. 38, 0. 38 and 0. 35, respectively, important value is 12. 46%, 24. 63%, 31. 97%, 38. 03% and 11. 48%, respectively, Bi value is 1. 278, 1. 190, 1. 047, 1. 046 and 1. 046, respectively. While frequency, important value and Bi value of Castanopsis eyrei ( Champ. ex Benth.) Tutch. and Crataegus cuneata Sieb. et Zucc. are basically lower, their frequency is 0. 21, important value is 11. 02% and 5. 95%, respectively, and Bi value is 0. 781 and 0. 654, respectively. Niche overlap degree among 14 dominant species is generally low, Oik value of 89. 01% species pairs is lower than 0. 4. It is suggested that niche breadth of dominant species at arbor layer in montane elfin forest of Jinggangshan is related to its important value, frequency, biological characteristics and interspecific relationship, and dominant species are weak in competition to common resources. In general, montane elfin forest of Jinggangshan is at a relatively stable stage.