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重庆喀斯特地区不同干扰生境中山麻杆种群的结构与格局

曾嘉庆,祝佳杏,王微,陶建平*   

  1. (三峡库区生态环境教育部重点实验室, 重庆市三峡库区植物生态与资源重点实验室, 西南大学生命科学学院, 重庆 400715)
  • 出版日期:2016-09-10 发布日期:2016-09-10

Population structure and spatial pattern of Alchornea davidii in different disturbed Karst habitats in Chongqing.

ZENG Jia-qing, ZHU Jia-xing, WANG Wei, TAO Jian-ping*#br#   

  1. (Key Laboratory of Ecoenvironments in Three Gorges Reservoir Region, Chongqing Key Laboratory of Plant Ecology and Resources of Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China).
  • Online:2016-09-10 Published:2016-09-10

摘要:

为了明确喀斯特地区人为干扰对山麻杆(Alchornea davidii)种群的影响,阐明山麻杆种群特征随着干扰强度变化的规律,采用样方调查法对喀斯特4种不同干扰强度生境(轻度、中度、重度及严重)中的山麻杆种群进行调查,分析其在不同干扰强度下的种群结构、动态及分布格局的差异。结果表明:(1)在中度、重度及严重干扰强度下山麻杆种群年龄结构为正金字塔型,种群增长明显,随着干扰程度的减弱,种群趋于稳定。(2)种群存活曲线在轻度和中度干扰下趋向于Deevey Ⅱ型,种群稳定;在重度和严重干扰下更趋向于Deevey Ⅲ型,种群增长性强。(3)轻度和中度干扰下的种群具有较高的存活率和生命期望,存活函数曲线和积累死亡率曲线波动较小,种群稳定。在严重干扰下,环境筛选强度大,幼苗进入中龄个体较少,老龄植株危险率高于低干扰等级种群。(4)不同种群动态量化指数Vpi和Vpi值均为正值,且Vpi和V′pi的值均随干扰等级的加重而明显增加,表明高干扰强度下的种群增长性更强。(5)不同干扰等级下的4个山麻杆种群在5种取样尺度上的分布格局均为聚集分布,轻度和中度干扰下聚块性指数高于重度和严重干扰下种群,表明高强度干扰下种群扩张性更强。因此,该种群适宜应用于喀斯特地区严重干扰过后的初期植被恢复中,有利于在短时间内迅速提高生境的植被覆盖。
 

关键词: 森林郁闭度,  , ICESat-GLAS,  , Landsat-TM,  , 多源遥感数据,  , 神经网络模型

Abstract: Alchornea davidii is an adaptive species, playing important roles in water and soil conservation in Karst areas. To analyze the differences of population structures, dynamics and spatial patterns of A. davidii, and further to provide guidance for its better use in vegetation restoration, a comparative study was carried out under four different disturbed (mild, moderate, strong and severe) Karst environments in Chongqing. The results showed that: (1) the population age structure presented an upward pyramid type and the population size kept growing under moderate, strong and severe disturbances. (2) Population survival curve followed a stable Deevey Ⅱ curve under mild and moderate disturbances, but a Deevey Ⅲ curve with a strong population increase under strong and severe disturbances. (3) Populations under mild and moderate disturbances had higher survival rate and life expectancy, and their survival rate and cumulative mortality rate had smaller fluctuation than those under strong and severe disturbances. The populations under severe disturbance suffered a severe environmental screening from the first age class to the second age class. (4) The values of dynamic quantitative index Vpi and V′pi increased with disturbance intensity, indicating that the populations had higher growing ability in highly disturbed environment. (5) All populations under different disturbances showed an obvious clumped distribution at five different plot sizes, and the patchiness index of populations in highly disturbed environments was lower than that in lowly disturbed environments, which suggested that the former populations were more expanding. Therefore, A. davidii is suitable for early stage vegetation restoration in Karst areas.

Key words: forest canopy cover, ICESat-GLAS, Landsat-TM, multi-source remote sensing data, BPneural network model.