【摘要】 全球环境变化将对森林生态系统凋落物的分解和养分循环产生直接和间接的多重影响。就全球环境变化如全球变暖、大气CO2浓度升高、UV-B辐射增强、氮沉降等对凋落物分解影响的研究进展进行了综合述评。影响凋落物分解的内部因素为凋落物基质质量,外部因素包括生物因素(微生物和动物)和非生物因素(温度、水分和土壤性质等)。全球变暖对凋落物分解的非生物作用有正效应,也有负效应。全球变暖对凋落物化学组成虽然只有轻微的影响,但可以通过影响植被的物种组成来间接改变凋落物的产量、化学性质和分解。全球变暖对凋落物分解生物作用的主要影响是增强土壤微生物活性,从而加速凋落物的分解。CO2浓度上升将增加凋落物产量,并通过影响凋落物质量(提高C/N比、木质素/N比等)和生物环境(微生物的数量和活性)而影响分解过程。UV-B辐射和大气N沉降的增加亦对凋落物分解产生直接和间接的影响,但影响效果尚不很清楚,有待进一步的研究。总起来看,全球环境变化将通过影响凋落物的分解速率而对全球碳循环产生重要影响,但由于气候变化和凋落物分解响应的复杂性以及各因子之间的相互作用,气候变化对凋落物分解的总效应尚需更深入的研究来定量化。更多还原

【Abstract】 The global environment change would affect litter decomposition and nutrient cycling directly and indirectly in forest ecosystem.The effects of global warming,elevated CO2,increased UV-B radiation and N deposition on litter decomposition was reviewed in this paper based on literatures.In general,the litter substrate quality,biotic factors such as microbe and animal,and abiotic factors including temperature,moisture and soil condition were the main factors affecting decomposition rate.Global warming made both positive and negative effects on abiotic factors.Although global warming slightly influenced the litter chemistry,however,it indirectly changed litter production,chemistry composing and decay through alter vegetation component.A temperature variable(annual mean temperature,effective temperature sum or its logarithm) combined with a summer drought indictor explained the first-year mass loss of the Scots pine needle litter across Europe and North America with a higher R2 value than actual evapotranspiration.Global warming also enhanced soil microbe activity and thereby accelerated decomposition.Elevated CO2 would increase litter production and affect decomposition by altering litter quality(e.g.improving C∶N and Lignin∶N ratio) and biotic environment such as microbe quantity and activity.Increased UV-B radiation and N deposition also affected decomposition,but the results were uncertainty as the absent of data.In addition,global environment change would obviously affect the C cycling through changing litter decomposition.Therefore,it is necessary to enhance the further research of global environment change and response of litter decomposition and the reciprocity of various factors due to the complex relationship.更多还原