雷州半岛谢鞋山群落特征沿海拔梯度变化趋势的分析

Variation Trend of Community Characteristics of Xiexie Mountain in Leizhou Peninsula along an Altitudinal Gradient

谢鞋山是雷州半岛保护最为完整的天然地貌和生态植被地区之一,保存了中国内陆唯一仅存的连片野生荔枝林,其植被类型为次生季雨林。通过对谢鞋山植被开展的实地调查,分析不同海拔样带的重要值和多样性指数,结果表明:占有绝对的优势地位的乔木分别为山脚的橄榄,重要值为71.93,山腰的荔枝为84.16,山顶的山杜英重要值为89.99;其次,灌木为粗毛野桐,重要值74.16,山腰的毛果巴豆重要值为72.81,山顶的罗伞树重要值为29.47;乔木层多样性指数H、优势度指数D、均匀度指数J等最高的为山脚,分别为2.266 8、0.860 6、0.750 6;灌木层最高的为山顶,分别为3.191 5、0.949 1、0.883 8。树种重要值和多样性指数均随着海拔梯度的变化发生明显的变化,随着海拔的升高,谢鞋山依次形成以橄榄、荔枝、山杜英为建群种,其树种多样性指数在乔木层呈现随海拔升高而降低趋势,在灌木层呈现随海拔降低而呈现先降低后上升趋势。

Xiexie Mountain, which is the most complete one of the natural landscape and ecological vegetation area in Leizhou Peninsula,holds the only remaining wild Litchi chinensis in China inland contiguous acres;the vegetation type of Xiexie Mountain is secondary monsoon forest. Developing research of vegetation characteristics in Xiexie Mountain are important. Important values ＆ diversity at different altitudes were analyzed on the basis of conducting field investigation on vegetation in Xiexie Mountain. Result shows that： the important value of Canarium album is 71.93 at the foot of the mountain, the important value of Litchi chinensis in mountainside is 84. 1G;the important value in the top of the mountain is 89.99 ;secondly,shrub is Mallotus hookerianus ,its important value is 74.1G ;ira portant value of Croton lachnocarpus in mountainside is 72.81;the important value of Ardisia quinquegona in top o f the mountain is 29. 47; diversity index of tree layer （H）,dominance index （D）, evenness index （J） are all highest at joothills, being 2.266 8,0.860 6, 0. 750 6, respectively ; H, D ＆ J in shrub layer are the highest, respec tiwely,being 3. 1915,0. 9491,0. 883 8. Species diversity and important value index of diversity index changed significantly zvith the change of the altitude gradient ; zvith increasing altitude, Xiexie Mountain sequentially formed edificatory （ Canarium album, Litchi chinensis ＆ Elaeocarpus sylvestris ） its diversity index of species appear decrease with the increase of altitude in tree layer;its diversity index of species appear decrease firstly and then increase with the decrease of the altitude in shrub layer.