A STUDY ON RESPONSES OF DOMINANT SPECIES TO ENVIRONMENTAL GRADIENTS IN GLYCYRRHIZA URALENSIS COMMUNITIES IN CHINA USING GENERALIZED LINEAR MODEL.

Glycyrrhiza uralensis is an important endangered medicinal plant species and requires special conservation in China. Its relationships with environmental gradients are significant for its conservation. The responses of dominant species to environmental gradients in G. uralensis communities were simulated by using the general linear model (GLM). The data were collected from 100 quadrats of 5 m x 5 m in five sites from east to west in northern China. The results showed that GLM was very useful in modelling species responses to environmental gradients. Precipitation and soil nutrients (soil N, P, K, organic matter and pH) were the variables that correlated most to G. uralensis populations, dominant species and communities. G. uralensis showed the greatest responses to all comprehensive and single gradients, and was absolutely dominant in communities. Its response pattern was unimodal, i.e. it increased and then decreased after reaching the highest value, to almost all environmental gradients. Other four dominant species showed different response patterns with slight variation. To protect G. uralensis populations and communities, the measures of soil and water conservation, improving soil nutrients, utilization management etc., should be considered. [ABSTRACT FROM AUTHOR]