百山祖常绿阔叶林优势种群的生态位

Niche of dominant species populations in an evergreen broad-leaved forest in Baishanzu

关键词:  常绿阔叶林, 优势种群, 生态位宽度, 生态位相似性比例, 生态位重叠, 百山祖

Key words:  evergreen broad-leaved forest, dominant species populations, niche breadth, niche similarity, niche overlap, Baishanzu Mountain

摘要:

为了理解百山祖中山常绿阔叶林各优势种群在群落中的关系、地位和功能,用定量分析法,对该群落中平均重要值大于1%的13个优势种群的生态位特征进行了研究。结果表明:多脉青冈、麂角杜鹃和窄基红褐柃的生态位宽度较大,它们的Hurlbert生态位宽度(B_a)分别为0.878、0.825、0.806; 而厚叶红淡比、亮叶水青冈和水丝梨的生态位宽度较小,它们的B_a分别为0.341、0.320、0.272。物种的生态位宽度与其重要值大小无关,但与其在各样方中的重要值均匀程度呈极显著的线性正相关。生态位相似性比例(C_ih)最大的是多脉青冈与尖连蕊茶(0.832),最小的是凸脉冬青和水丝梨(0.248)。对生境需求相似而生态位宽度较小的厚叶红淡比与亮叶水青冈的C_ih高达0.758。同属植物多脉青冈与褐叶青冈、台湾冬青与凸脉冬青之间并不具有较大的C_ih值。生态位宽度较大的物种与其他物种的生态位重叠值一般较大; 生态位相似性比例大的物种的生态位重叠值一般较大。多脉青冈与褐叶青冈、台湾冬青与凸脉冬青的生态位重叠值并不大。总体来看,群落优势种群之间的生态位重叠程度较低,说明该群落主要优势种群之间竞争不激烈,群落稳定。该研究揭示了群落优势种群的生态位特征和结构稳定性,为生物多样性保护、群落演替和种群进化等研究提供了理论基础,也为自然保护区管理机构制定和完善保护措施提供参考依据。

Abstract:

Dominant plant populations have great ability to adapt to the environment and use resources, and they play a decisive role in the community structure and function. What's more, the species niche characteristic reflects the utilization of environmental resources from a perspective. In order to explore the relationship, position and function of each dominant species population in an evergreen broad-leaved forest of Baishanzu, nine subplots of 20 m×20 m regularly from the 5 hm²(250 m×200 m)plot which established in 2003 were selected, where all trees with DBH≥1 cm were tagged, measured, and identified to species. The niche breadths, niche similarities and niche overlaps of 13 species(importance value larger than 1%)were analyzed quantitatively based on the data collected in 2013. The results demonstrated that the niche breadths of Cyclobalanopsis multinervis, Rhododendron latoucheae and Eurya rubiginosa var. attenuate were relatively larger, with Hurlbert niche breadth values(Ba)being 0.878, 0.825, 0.806, respectively, while the niche breadths of Cleyera pachyphylla, Fagus lucida and Sycopsis sinensis were relatively smaller, with Ba values being 0.341, 0.320, 0.272, respectively. The species niche breadth was not related to its importance value, but was significantly positively correlated with the evenness of importance values across different plots. The niche similarity between Cyclobalanopsis multinervis and Camellia cuspidate was the largest, being 0.832, while that between Ilex editicostata and Sycopsis sinensis was the smallest, being 0.248. Despite of small niche breadths, in addition, the niche similarity between Cleyera pachyphylla and Fagus lucida was high(0.758)due to their similar habitat requirements. Low niche similarities were found in two pair of species in the same genus: between Cleyera multinervis and C. stewardiana, and between Ilex formosana and I. editicostata. Species with wide niche breadth often had high degrees of niche overlap with other species, and large niche similarity was often associated with high degrees of niche overlap. Low degrees of niche overlap were found between Cleyera multinervis and C. stewardiana, and between Ilex formosana and I. editicostata. In a word, low degrees of niche overlap found in this study suggested weak interspecies competition among dominant species and therefore a potentially stable plant community in this forest. This paper revealed the niche characteristics of dominant species populations and structural stability of the community, and it would provide theoretical basis for the research of biodiversity conservation, succession, population evolution. And it also could provide reference for the nature reserve management institution to adjust and improve conservation measures.