秦岭植被景观多样性与物种梯度分析

Vegetation landscape diversity and gradient analysis of plant species in Qinling Mountain

秦岭植被景观类型丰富，具有过渡性和复杂性特点，植被垂直分带明显，在分析秦岭植被景观空间分布格局的基础上，利用植被景观多样性指数，分析了秦岭山地植被景观的数量统计特征与海拔的变化关系；利用基于GIS的梯度分析方法，分析了秦岭的植被与海拔梯度的关系，得到秦岭不同植被景观类型的斑块数、分布范围、植被分布的高度均值和标准差，并以太白山为例，对太白山植物种进行了梯度分析。结果表明：秦岭各植被型的多样性指数Simpson指数D、Shannon-wiener指数H’和均匀度指数基本上呈相同的变化趋势，随着海拔的增加，呈波浪式的变化趋势。自然植被在海拔1325m、1500m和2930m时出现峰值。乔木的多样性指数在海拔1500m和2930m时达到最大值。在海拔1200～1470m和1600-2650m左右处，乔木的多样性指数值较小，但均匀度指数却较高；灌木的多样性指数在海拔1325m时达到最大值；草本的多样性指数呈波浪式上升的趋势，海拔2400m和3500m左右处有2个峰值。随着海拔高度的增加，太白山依次出现温带草丛→温带落叶灌丛→温带落叶阔叶林→亚热带针叶林→亚热带和热带山地针叶林→草甸→高寒草甸等植被类型，并随海拔的升高，依次出现相应的植物种。

Vegetation types of Qinling Mountain are rich and have characteristics of transition and complexity, and the vertical belts are evident too. This paper, applies the diversity index based on the spatial patterns of vegetation, analyses the change relationship between the quantity statistical features of mountain vegetation and altitude. Using the gradient analysis method based on GIS, this article analyses the effects of altitudinal gradient on vegetation of Qinling Mountain, and the results of patches＇ sum, distribution range, mean value, standard deviation of different vegetation types are calculated. Exemplified the plant species of Taibal Mountain, the gradient analysis method is conducted in the following parts. The conclusions are as follows： Simpson index, Shannon-wiener index and Pielou evenness index of vegetation types appear almost the same undulant change trend with the rise in height in Qinling Mountain, and the diversity index value of natural vegetations reaches the peak value at the altitude of 1 325 m, 1 500 m and 2 930 m. The diversity index value of tree reaches the peak value at the elevation of 1 500 m and 2 930 m, and diversity index value is smaller at the altitude of 1 200 - 1 470 m and 1 600 2 650 m, but the evenness index value is a little larger oppositely. The diversity index value of shrub touches the crest value at the altitude of 1 325 m. The diversity index curve of herbosa is rise like waveform with the increase of altitude and has two peak values at the elevation of 2 400 m and 3 500 m. The results of gradient analysis of Taibai Mountain tell us, there suceemively appear vegetation types of temperate grassland→temperatedeciduous scrub→temperate deciduous broad-leaved forest→subtropieal coniferous forest→subtropical and tropical mountain coniferous forest→meadow→high-cold meadow, and there successively appear corresponding plant species at certain altitude.