湖南南岭草地植被类型的数量分类、排序及其合理利用

湖南南岭山区的地带性植被是常绿阔叶林,由于不合理的利用,森林遭受严重破坏而出现了大面积的草山,面积约1497.2万亩(99.8万ha),占土地总面积的1/4强。本文运用二元指示种分析TWINSPAN和无倾向对应分析DCA的数学方法对草地植被进行分类与排序。利用48个样方和150个植物种的资料进行计算,在第4级水平上划分出12个主要草地植被类型,其中将近似的类型合并成10个类型。在第1级水平上明显地将海拔1000m以上的与600m以下的分成2大组;在其它水平上则根据其他不同生态因子(岩性、pH值等)将出现的区别种逐级分开。所得结果与定性分类基本相同,说明该方法是适用于亚热带草地分类的。 不同类型在开发利用上有很大差异,高海拔的植被类型应以造林或封山育林为主,并可适当发展木本药材;在平缓的山原上虽可开辟人工草地发展畜牧业,但必须要防止水土流失,坡度在25。以上的应封育;15—20°的地方可以发展林业与畜牧业;在海拔300—600m的丘陵岗地类型上可以发展薪炭林、经济林;在海拔300m以下,水源充足的地方可以发展果木林(柑桔等),缓坡丘陵地类型可建立人工草地,但应与林业相结合,在农区可进行粮草轮作。总之,应该建立人工生态系统,以提高经济效益和生态效益。

THE QUANTITATIVE CLASSIFICATION, ORDINATION AND RATIONAL UTILIZATION OF GRASSLAND VEGETATION TYPES OF THE NANLING MOUNTAINS, HUNAN PROVINCE

The zonal vegetation of the Nanling Mountains in Hunan Province is evergreen broadleaf forest. Due to unrational utilization of the land, many forests are severely destroyed and large areas of grassland have occurred. The total area of grassland is about 1497.2×107mu (9.98× 105 ha), occupying more than one fourth of the whole region. The classification and ordination of the grassland vegetation are studied with the numerical methods of TWINSPAN (Two-way indicative species analysis) and DCA (Detrended correspondence analysis). The methods use the data of 48 plots and 150 species for calculating. The plots of the fourth division are divided into 10 main vegetation types. At the first division level, the plots are distingguished into two types, the mountain grassland type (occurring at elevations of more than 1000 m) and the hill grassland type (occurring at elevations of less than 600m). The other levels are based on difference of ecological facters. The results are very similar to those of the qualitative classification, which demonstrates that the methods of TWINSPAN and DCA are suitable for the classification of the subtropical grassland.Distinctive types have different utilization ways. The types on the higher mountains should be dominated by forestry. At some place medicinal trees can be planted. At the places of the gentle slopes it is possible to establish artificial grassland for pasturage under paying attention to soil erosion- The slopes of over 25 degrees should be closed. At the places having slopes of 15-20 degrees it is suitable to develop both forestry and pasturage. The hills about 300-600m in elevation may be used for cultivating economical forests and fuel forests. Below the elevation of 300 m the fruit gardens (citrus) can be established if there is irrigation. On the hills of gentle slopes the artificial pasture ground can be developed, but it should be combined with forestry. In agricultural areas the rotation of cereal crops and forage grass should be put into practice. It is most important to increase the ecological and economical benefits.