植物生态学报 ›› 2008, Vol. 32 ›› Issue (6): 1335-1345.DOI: 10.3773/j.issn.1005-264x.2008.06.014

• 研究论文 • 上一篇    下一篇

太白山红桦种群结构与空间分析

林玥, 任坚毅, 岳明()   

  1. 西北大学西部资源生物与现代生物技术省部共建教育部重点实验室, 西安 710069
  • 收稿日期:2007-12-07 接受日期:2008-06-16 出版日期:2008-12-07 发布日期:2008-11-30
  • 通讯作者: 岳明
  • 作者简介:*(yueming@nwu.edu.cn)
  • 基金资助:
    国家自然科学基金(30370269);国家自然科学基金(30670366);教育部留学回国人员启动基金

POPULATION STRUCTURE AND SPATIAL ANALYSIS OF BETULA ALBO- SINENSIS AT TAIBAI MOUNTAIN, NORTHWESTERN CHINA

LIN Yue, REN Jian-Yi, YUE Ming()   

  1. Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi’an 710069, China
  • Received:2007-12-07 Accepted:2008-06-16 Online:2008-12-07 Published:2008-11-30
  • Contact: YUE Ming

摘要:

为了揭示太白山红桦(Betula albo-sinensis)种群的维持机制, 结合径级结构、静态生命表和存活曲线, 对太白山红桦种群结构进行了研究; 并应用单变量、双变量K函数对不同径级立木与残干的空间格局、空间关联性进行了多尺度分析。研究显示, 太白山红桦种群在幼苗幼树阶段死亡率较高, 进入中龄期后死亡率有所降低, 随着年龄增长, 死亡率逐渐增加, 直至年龄极限。其存活曲线基本接近Deevey I型(曲线凸型)。其个体死亡方式主要为掘根和折干(由大雪所致), 能够为种群更新提供潜在空间。除海拔2 250 m立木整体格局呈集群分布外, 该地区红桦立木与残干在不同尺度下的整体格局均为随机分布。不同发育阶段的个体均呈集群分布, 表现为斑块状同龄群。在红桦更新所需的最适林窗大小尺度上, 红桦立木与残干的空间关联性为显著正相关。以上结果表明: 太白山红桦种群具有同龄集群生长的特性, 种群由时空上不连续的局部斑块同龄个体组成, 其更新有赖于以掘根及折干方式死亡个体所形成的林窗斑块, 这种以局部林窗斑块更新维持种群整体稳定的特性, 可能是其长期稳定存在的重要机制。

关键词: 空间格局, 点格局分析, 年龄结构, 更新, 种群, 红桦

Abstract:

Aims Our objective was to understand the population structure, spatial pattern and recruitment mechanism of Betula albo-sinensisforest at Taibai Mountain, northwestern China.

Methods Using data collected from 0.75 hm2 plots, we determined the life table, age structure and survivorship curve of the B. albo-sinensis population. Univariate and bivariate Ripley’sK functions were employed to determine spatial distribution of standing trees and snags in different age classes and correlate standing trees and snags.

Important findings The B. albo-sinensis population had high mortality of seedlings and saplings, stable growth of adult trees and then gradually increased mortality. The survivorship curve of B. albo-sinensis population matched Deevey Type I. Snags mostly developed by uprooting and snapping, producing disturbed microsites that recruitment probably relied on. Standing trees and snags were clustered by each age class but randomly distributed when all classes were combined. Standing trees above a given size formed snags in pulses at a scale that was also the optimum canopy gap size for establishing. Population dynamics are related to spatial pattern and provide a measure of ecological significance between population structure and spatial patterns. As a sun-loving species,B. albo-sinensis requires disturbed microsites (e.g., sites of uprooting and snapping) and canopy openings for regeneration in the forest. Patterns in the distribution of standing trees appear to persist and were consistent with highly aggregated patterns of snags caused by natural disturbances across the stand. Findings suggest that cohorts of the B. albo-sinensis population at Taibai Mountain are spatially clumped and the aggregation of different cohorts represents pulsed recruitment that might be capable of maintaining population stability.

Key words: spatial pattern, point pattern analysis, age structure, canopy gap, recruitment, snags, population, Betula albo-sinensis