井冈山国家自然保护区栲树林优势种群生态位特征

Niche characteristics of dominant species populations in Castanopsis fargesii forest in Jinggang mountain national nature reserve

在对井冈山国家自然保护区常绿阔叶林林分调查的基础上,选择有栲树分布的不同环境类型设置8个典型样地,以不同生境的样地作为资源位,以物种重要值作为资源位上的状态指标,对栲树林优势种群的生态位宽度、生态位重叠和生态位相似性比例进行分析。结果表明:栲树、罗浮栲、红楠具有较大的重要值和较宽的生态位宽度值,Ba为0.853、0.787、0.720,对群落结构和功能起着决定作用。杜英仅在两个资源位中出现,分布范围小,Ba为0.026,对资源利用能力弱;15个优势树种间的生态位高度重叠占4.8%,中度重叠占35.2%,低度重叠占60%,生态位重叠值不大,各树种因对共同资源的利用而产生的竞争不强,群落中优势树种间生态学习性相似,多数树种间生态位相似性比例大。综合分析表明,栲树林群落组成树种对研究区的环境适应性强,对资源利用充分,种间的竞争小,处在相对稳定的阶段。

Based on the field survey to Jinggang Mountain National Nature Reserve evergreen broad-leaved forest, 8 environmental types for Castanopsis fargesii were selected. Using the plots which in different environmental types as resource state, and the species of important value as the state index on resource state to quantitatively analyzed the breadth, overlap, similarity of the niche dominant species populations in Castanopsis fargesii community. The results showed that： the Castanopsis fargesii, Castanopsis fabric and Machilus thunbergii had great important value and wide niche breadth. Their Hurlbert niche breadth values were 0.853、0.787、0.720, respectively. They played a decisive role in the community structure and function. The Elaeocarpus decipens only appeared in two resource states and it＇s weak in resources utilization capacities. Its Hurlbert niche breadth value was 0.026; the niche overlapping of 15 dominant species populations included three degrees which consisted of high overlap, moderate overlap and low overlap, high overlap accounted for 4.8%, moderate overlap accounted for 35.2% and low overlap accounted for 60%.The low overlap found in this study suggests less fierce interspecies competition for communal resource utilization in the Castanopsis fargesii forest. There is a larger niche similarity among most of the dominant species in the Castanopsis fargesii forest, the ecological characteristics of them were similar. Comprehensive analysis shows that, the species of the Castanopsis fargesii forest had higher ability and resource utilization in the study area, and the interspecies competition was not intense. The community was in the relativeiy stable stage.