摘要
保留木是指森林生态系统受到强度干扰后所存留的树木,保留木对退化森林生态系统结构与功能的维持和恢复具有多方面的生态效应。在生态系统的尺度上总结了退化森林生态系统中保留木的各种生态效应,主要包括保留木对非生物因子和生物因子(附生生物多样性、动物活动和动物多样性、树木更新、空间结构)的影响。森林生态系统经营中,"绿树保留"的经营方式是基于保留木生态效益的实践应用,它可有效减少采伐对生态系统结构和功能所造成的损失。并将有助于深入理解受到强度干扰后森林生态系统中保留木的多种生态效应,可为退化森林生态系统的恢复与重建提供理论依据。
Remnant trees,which remain as a biological legacy in degraded forest ecosystems after severe disturbances,have been found to have had many positive ecological effects on the maintenance and recovery of ecosystem structure and functions.Remnant trees serve to reduce the impacts of human disturbances such as logging and habitat transformation on elements of biodiversity.This paper presents an overview on the main ecological effects of remnant trees on abiotic and biotic factors in degraded forest ecosystems based on relevant studies.With regard to abiotic factors,usually,remnant trees serve to regulate local micro-climate and site conditions and improve soil microbial activities and soil nutrient cycle through input of litter from leaves,branches,fruits,etc.However,the effects of remnant trees on the preservation of non-biological environments and improvement of micro-habitat conditions vary significantly in different forest ecosystems.With regard to impact on biotic factors,first,remnant trees in fields may facilitate natrual regeneration by attracting seed dispersers and creating favorable site conditions for re-establishment of woody vegetation.Remnant trees serve as seed dispersal foci and thus as starting points of a spatial pattern process initiating forest regeneration.These forest regeneration foci of remnant trees enhance the recruitment of trees and further influence the spatial pattern and structure of forest regeneration of these ecosystems and consequently increase the complexity of community structure.In addition,remnant trees also provide favorable microhabitats for the establishment of seedlings of late-successional tree species.Therefore,remnant trees,by the establishment of focal points of forest regeneration,facilitate a more rapid forest restoration and the conservation of nutrients in the accumulation of woody plant biomass.Second,remnant trees may have positive effects on the re-establishment of forest birds and mammals by providing suitable habitats,which have largely been lost in most seriously degraded forest ecosystems.As measured by increases in animal species richness and diversity,remnant trees appear to add significant habitat value to degraded forest lands.The degree of influence on animal activities and species diversity by remnant trees depends on the species,volume and density.Third,remnant trees often retain some of plant species which originally lived on or under those trees,which also can contribute further to the recovery of forest plant diversity.Especially,the canopies of remnant trees have remained potential refuges for some forest mosses,epiphytes and lichens,which are also remnants from the original intact forest ecosystems.Epiphytic plants may often have interactive relationships with the host remnant trees.Fourth,the deliberate retention of remnant trees can be incorporated in practical forest management,i.e.,the application of ＇green-tree retention＇ in forest harvesting in order to reduce the damages to ecosystem services and functions caused by extensive tree removal management.While leaving remnant trees may appear to reduce short-term commercial profits,the application of ＇green-tree retention＇ serves to enhance wildlife habitat,biodiversity,and ecosystem function,including soil protection and nutrient retention and,ultimately,promote the natural regeneration of the forest ecosystem.Therefore,we suggest that remnant trees play a significant role in providing suitable substrate and starting engine for the restoration of degraded forests induced by severe disturbances.There are a variety of forest ecosystems under frequent and different disturbance regimes（logging,fire,hurricane,etc.） in China.However,remnant trees are only used as a concept but actually no practical application in forest management,and their ecological effects have still draw little attentions so far in China.Therefore,a high research priority should be given to ecological effects of remnant trees in various forest ecosystems in order to provide useful knowledge for guiding degraded forests ecosystem restoration and rehabilitation.
出处
《生态学报》
CAS
CSCD
北大核心
2013年第13期3889-3897,共9页
Acta Ecologica Sinica
基金
国家自然科学基金项目(31200477)
国家“十一五”和“十二五”科技支撑计划项目(2012BAD22B01,2006BAD03A04)资助
关键词
保留木
退化森林
生态效应
干扰
森林生态系统
恢复
remnant trees
degraded forests
ecological effects
disturbances
forest ecosystems
restoration
