摘要:
九寨-黄龙世界自然遗产地位于我国西部典型的山地生态脆弱区,自2001年以来松潘县在退耕还林工程进行了不同树种配制模式的实践,共计营造了12个生态经济林模式.它们分别为:1.枸杞,2.沙棘,3.山桃+云杉,4.山杏+云杉,5.云杉,6.西蜀丁香+陇东海棠,7.云杉+阿根廷柳,8.云杉+青杨,9.阿根廷柳,10.阿根廷柳+青杨,11.青杨,12.山杏+阿根廷柳模式.通过对这12个模式群落与各层次物种多样性的分析比较,发现绝大多数模式木本层多样性并不高,而草本层则物种数多为20种左右,香农威纳指数都达到2.0以上,因而,群落总体多样性很可观.运用Godron M稳定性测定方法检验其生态稳定性表明:各模式的生态稳定性与理论上20/80的稳定点尚有相当距离;其大小依次为:1.枸杞,2.沙棘,4.山杏+云杉,6.西蜀丁香+陇东海棠,10.阿根廷柳+青杨,12.山杏+阿根廷柳,5.云杉,8.云杉+青杨,7.云杉+阿根廷柳,11.青杨,9.阿根廷柳,3.山桃+云杉,这表明模式构建后仍处在较脆弱的状态.稳定性与其多样性之间的拟合也表明稳定性与多样性并无多少明显相关,甚至还有呈现负相关的趋势.这预示着多样性与稳定性之间不存在简单的线性关系,而是可能存在一个多样性阈值.
Abstract:
The World Natural Heritage-Jiuzaigou & Huanglong-is located in the eco-vulnerablele areas of West China. Since 2001, a total of 12 reconstruction models of the degraded landscape in the eco-vulnerable areas have been implemented in Songpan County, i. e. 1) Lycium chinense; 2) Hippophae rhamnoides;3) Amygdalus davidiana + Picea asperata ; 4) Armeniaca sibirica + P. asperata; 5) P. asperata; 6)Syringa komarowii +Maluskansuensis; 7) P. asperata + Salix argentinensis; 8) P. asperata+ Populus cathayana; 9) S. argentinensis; 10) S. argentinensis + P. cathayana; 11) P. cathayanaand 12) A.sibirica+ S. argentinensis. An analysis of both horizontal and vertical species diversity in these 12 models showed that there were generally poor species richness and diversity in the woody layer. In contrast, the herb layer of most models possessed considerable diversity, with about 20 species and a Shannon-Weiner index of over 2.0. In addition, most models possessed sound species diversity, contributed by diversity in the herb layers. Estimation of bio-stability with M. Godron stability method demonstrated that the ecostability of each model fell quite apart from the theoretic stable point (20/80), being in the sequence of L.chinense > H. rhamnoides > A. sibirica+ P. asperata > S. komarowii + M. kansuensis> S. argentinensis + P. cathayana> A. sibirica + S. argentinensis > P. asperata > P. asperata + Populus cathayana > P. asperata + S. argentinensis > P. cathayana > S. argentinensis > Amygdalus davidiana + P. asperata, indicating that these models remained in their fragile status. Simulation between their species diversity and ecological stability also indicated that little, if any, simple linear correlation existed between them and, sometimes, even a negative correlation was shown, suggesting that there may be a threshold of biodiversity other than a simple linear relationship between diversity and stability.
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