生态干扰度:一种评价植被天然性程度的方法

Hemeroby--A Method to Assess the Naturalness of Vegetation

地球上现存的植物或森林群落都是植被与其环境长期适应及人类长期干扰影响的结果 ,因此 ,现实的植被反映着历史上人类对它们不同程度的影响。‘生态干扰’的概念常常被用来描述历史上人类对植被或森林影响的大小 ,即‘生态干扰度’;或用来表示现实植被离开它的‘天然植被’的距离 ,即现实植被的‘天然性程度’。如此的‘天然植被’可以是 :( 1 )历史上从未受过人类任何干扰的‘原始植被’;( 2 )基于当前立地的‘潜在的自然植被’。然而 ,成百上千年以来人类对自然的利用干扰 ,致使真正的‘原始植被’现在几乎无处可寻。因此 ,‘潜在的自然植被’被用来作为生态干扰度估计或植被天然性程度评价的参照系。作为一种很实用的生态分析手段 ,生态干扰度的方法已被广泛地应用在农、林、水、景观、城市及自然保护等诸多领域的生态评价上。为此 ,本文论述了生态干扰度的概念、原理、方法和应用实例。

Present plant/forest communities are the result of long term interactions between vegetation and site factors including man made impacts. Present vegetation in the cultural landscape shows graduations of different intensities of human activities in the past. To assess the degree of naturalness and/or the anthropogenic influences on the present vegetation/forests,the concept of hemeroby is often used. The degree of hemeroby is defined as degree of human cultural activities; at the same time it is a degree of distance to the natural state of vegetation. Such a natural state of vegetation may be pristine vegetation or potential natural vegetation. Because pristine vegetation was destroyed or modified by the humankind all over on the earth,the basis of naturalness assessment is the present potential natural vegetation including successive development under today's site conditions. The evaluation of the level of hemeroby can be used as an ecological tool that has been widely applied to ecology of agriculture,forestry,water,landscape,urban and nature reserves. This paper discusses the concept of hemeroby and its application including field observation.