Spatial variability of plant functional types of trees along Northeast China Transect

Abstract

Studying the spatial variability of plant functional types at large scale is important to understand the effects of environmental change on ecosystems. Here we classified the tree species in the forest area of Northeast China Transect (a middle-latitude transect and its environmental gradient was mainly driven by moisture) into three plant functional types (PFTs): drought tolerant, drought intolerant and middle type PFTs. We found that the average percentage of the drought intolerant and middle type of PFTs both increased significantly from 1986 to 1994. The drought tolerant and middle type of PFTs increased their covered areas at the western part of transect, but the covered area of the drought intolerant PFTs decreased about 48% at the western part. The dominance of the drought intolerant PFTs decreased while the dominance of the other PFTs increased. The net increments of these three PFTs were higher at 0-220 km than at 220-400 km. The negative net increments concentrated mainly at 150-350 km. The spatial autocorrelation of the drought intolerant and middle type of PFTs changed slightly from 1986 to 1994. The information entropy of the drought intolerant PFT increased across all scales and it indicated that impact from local disturbances was limited. All these indicate that the drought intolerant PFTs is vulnerable to the current environmental change. The spatial variations of different PFTs at large scales were mainly caused by the fluctuations of gradient of annual precipitation along this transect. © 2005, Penkala Bt.