紫茎泽兰在云南亚热带常绿阔叶林中的入侵格局和生境分析

Invasive patterns and habitat analyses of Eupatorium adenophorum in the subtropical evergreen broad-leaved forest of Yunnan province

【目的】调查云南亚热带常绿阔叶林中紫茎泽兰Eupatorium adenophorum的个体生长情况和种群分布规律,分析其与各环境因子之间的相关关系和显著性,为保护森林物种多样性和防止外来入侵种的繁殖扩散提供科学建议和理论依据。【方法】以云南亚热带次生常绿阔叶林为研究对象,沿林缘随机挑选9个紫茎泽兰种群集中分布区域作为起点,垂直进入森林内部,以10 m为间隔等距离定点调查样方,分别调查紫茎泽兰植株外部形态指标和环境因子。【结果】株高、丰富度、单株最多绿色叶片数、单叶最大面积、单位面积生物量、存在度和重要值在林缘0~10 m的范围内达到最大值,且随着进入森林内部距离的增加而逐渐降低或减少,呈衰减指数模型分布;在距林缘超过60 m的森林内部很少有紫茎泽兰植株出现。土壤温度、光照强度、空气温湿度和林冠郁闭度均能明显控制紫茎泽兰种群的分布和生长。土壤温度、光照强度和空气温度与紫茎泽兰种群外部形态指标呈正相关关系;空气湿度和林冠郁闭度则与其呈负相关关系。【结论】由森林分布斑块化和物种生境碎片化产生的大面积林缘区域给紫茎泽兰种群的入侵和繁殖提供了理想栖息地,而森林内部相对较低的土壤和空气温度、较弱的光照强度、较高的空气湿度和林冠郁闭度则明显抑制了紫茎泽兰种群的入侵和生长。

【Objective】Through investigating the individual growth and population distribution of Eupatorium adenophorum Spreng.in the subtropical evergreen broad-leaved forest in Yunnan province,this study analyzed the correlation and significance between its growth and various environmental factors and provided some scientific suggestions and theoretical bases for protecting plant diversity in the forests and preventing the reproduction and diffusion of the alien invasive species.【Method】This study took the subtropical secondary evergreen broad-leaved forest in Yunnan province as the research object,randomly selected 9 areas with the centralized distribution of E.adenophorum populations as the starting point along the forest edge,vertically extended into the forest,established the investigation plots with the same distance at the 10 m intervals,and respectively investigated the external morphological indices of E.adenophorum and the environmental factors.【Result】The data including plant height,individual richness,maximum green leaf number of single plant individual,maximum area of single leaf,plant primary production per unit area,presence and important value of plant population all reached the maximum values within the 0-10 m range of forest edge,and gradually decreased with the increase of the distance extending into the forest,showing the distribution patterns of the decay exponential model;extremely less individuals of E.adenophorum appeared in the areas more than 60 m away from the forest edge.Environmental factors including soil temperature,light intensity,air temperature and humidity,and forest canopy closure could apparently control the population distribution and growth of E.adenophorum.Environmental factors including soil temperature,light intensity and air temperature were positively correlated with the external morphological indices of E.adenophorum;the air humidity and forest canopy closure were negatively correlated with them.【Conclusion】The large area of forest edge resulting from the distribution of patches and species habitat fragmentation in forests provide an ideal habitat for the invasion and propagation of E.adenophorum population,while the relatively low soil temperature and air temperature,weak light intensity,high air humidity and canopy closure in forests apparently inhibit the invasion and growth of E.adenophorum population.