黄河小浪底退耕还林后群落特征的研究

Comparative Studies Community Attributes between Ecological and Economic Forests Converted Form the Farmland in Xiaolangdi of the Yellow River

对比研究了黄河小浪底地区在退耕还林后的群落特征。结果表明,生态公益林中共有植物119种,农林生态系统中共有植物105种。生态公益林与农林复合经营的群落的相似性较低,它们之间共有种为33种,而特有种数分别为86种和72种。生态公益林中的坡顶灌草丛、侧柏林、刺槐林和栓皮栎林中的物种重要值比较一致,不同于荒坡和坡底路边灌草丛植物;农林生态系统的物种重要值与生态公益林有所不同,植物主要是以草本为主。对于植物的空间分布格局,其中在水平结构上,生态公益林和农林生态系统中的植物以聚集分布为主,随机分布为辅,未出现均匀分布状况;在垂直结构上,生态公益林中的乔木层、灌木层和草本层都具有一定的层次性,垂直分布的复杂程度较高。而在农林生态系统中,场院和弃耕地中的植物垂直分布差异显著,田埂上的植物垂直分布差异不显著。调查发现,退耕还林后,生态公益林和农林生态系统的群落生物多样性都显著增加,且生态公益林的Simpson多样性指数比农林生态系统高,其物种的丰富度是农林生态系统的1.2倍。在生态公益林中,侧柏林和刺槐林的Simpson多样性指数明显高于栓皮栎林,物种数为刺槐林>侧柏林>栓皮栎林,且Pielou均匀度指数也呈现相同的趋势;在农林生态系统中,耕作区上的植物丰富度和Pielou均匀度均高于农林复合经营的其他区域。

The objective is to compare the community attributes of the ecological forests and economic forests after returning farmland to forest in Xiaolangdi of the Yellow River. The results show that there are 119 and 105 species in the ecological forests and economic forests, respectively. Similarity of the two communities is extremely low, on the grounds of the study sites there are 33 species shared by the two communities and there are 86 and 72 species restricted only in each of the communities, respectively. The species＇ important values among the forests of Quercus variabilis, Robinia pseudoacacis, Platycladus orientalis are more similar than wilderness and roadside in ecological forests. However, the species＇ important values in economic forests are quite different from that the ecological ones which dominant vegetation is herbage. The spatial distribution pattern is studied, the results make clear that distribution patterns in horizontal structure of the ecological forests and economic forests are mainly aggregation distribution and subordinately random distribution, and no uniform distribution is found. According to vertical structure, the hierarchy of the tree, shrub and herb layers in ecological forests is significant, in economic forests, there are significant differences between farmyard and abandoned land, but the vertical structure in bund is not different. The community diversity increases rapidly after conversion of farmland to forest, in details, the Simpson＇s diversity indices in the ecological forests are higher than the economic forests and the richness indices are 1.2 times as long as the economic forests. In the ecological forests, the Simpson＇s diversity indices in the forests of Robinia pseudoacacis and Platycladus oriental,s are much higher than Q. variabilis. Ranked the species number is R. pseudoacacis 〉 Platycladus orientalis 〉 Q. variabilis, which is consistent trend with the Pielou＇s evenness index. In the economic forests, the richness and the Pielou＇s evenness in the farmland are higher than other areas.