我国中东部不同气候带成熟林凋落物生产和分解及其与环境因子的关系

Abstract

Production and decomposition of plant litter is one of the most important processes in terrestrial ecosystems.This process could be affected by climate,which elucidates that the spatial patterns and environmental regimes,which regulate the process,are essential to understand the mechanism of ecosystem functioning in both local and broad scales.However,the pattern of the process in large scales along environmental gradients in mid-and eastern China was poorly understood.The aim of the present work was to quantify litter production and its decomposition rate in forest ecosystems from subtropical to temperate zones with a view to gaining further insights into the recycling of above-ground organic matter.Data from 72 plots in six major forest types in China was used to clarify litter production and decomposition in six forest ecosystems and their relations with environmental factors in different climatic zones including Huzhong in Heilongjiang province,Mt.Changbai in Jilin province,Mt.Dongling in Beijing municipality,Mt.Gutian in Zhejinag province,Shennongjia in Hubei province,and Dujiangyan in Sichuan province.The storage of litter fall was in the sequence of: ShennongjiaDujiangyan Mt.gutianMt.DonglingMt.ChangbaiHuzhong.The annual litter production for Shennongjia,Dujiangyan,Mt.gutian,Mt.Dongling,Mt.Changbai,Huzhong were averaged at 910.98,830.18,574.06,396.19,374.64,and 249.29 gm-2a-1,respectively.Annual litter fall production was highly significant in relation to forest type and positively related to mean annual temperature,but was not significantly related to mean annual precipitation.There were two litter fall peaks in the subtropical forests in a year,one in spring(from April to May) and the other in autumn(October and November),while there was just on peak in the cold temperate,temperate and warm temperate forests,which occurred in autumn(from September to October).The litter decomposition rate(k) was consistent with litter fall production,and the k value decreased with increasing latitude.The annual litter decomposition rate(k) for Shennongjia,Dujiangyan,Mt.gutian,Mt.Dongling,Mt.Changbai,Huzhong were averaged at 0.13,0.26,0.36,0.79,0.92,and 0.8,respectively.A simple regression model was capable of explaining the majority of climatic effects on litter production and the decomposition rates of various litter types tested in different environments over geographical regions.In conclusion,mean annual temperature is the most important environment variable affecting litter decomposition rate,followed by mean annual precipitation.