摘要
草地生态系统具有固碳增汇、防风固沙和维持生物多样性等多种生态服务功能。当前部分地区草地退化问题日益严重,亟需深入解析退化草地植被恢复的限制因子,为天然草地植被恢复实践工作提供科学理论支撑。该研究基于内蒙古典型草原的13个采样点(每个点包含4种不同退化程度的植物群落:未退化、轻度退化、中度退化和重度退化)调查,探究了植物群落属性(地上生物量、盖度和密度)随草地退化程度的变化规律,并利用最小二乘回归分析、冗余分析和多元线性回归分析等多种统计分析方法解析了退化草地植被恢复的养分限制因子。结果显示:1)随着退化程度的加剧,内蒙古典型草原植物群落地上生物量、盖度和密度以及土壤有机碳、总氮和速效磷含量显著降低。2)整体退化阶段以及相邻的退化演替阶段之间,土壤氮含量是对植物群落属性变化最大的影响因素,土壤磷含量仅在草原整体退化阶段具有一定影响。上述结果表明,土壤氮的可利用性是内蒙古典型草原退化植被恢复最重要的养分限制因子,在退化草原恢复工作中应发展以氮肥施用为主的养分管理措施。
Aims Soil extracellular enzymes are crucial for soil organic matter decomposition and nutrient cycling.Soil enzyme activity and stoichiometry can provide insights into microbial resource limitations and soil nutrient availability.This study investigated the effects of grazing,particularly overgrazing that often leads to grassland degradation,on soil enzyme activity and stoichiometry,and identifies nutrient limitations in temperate grasslands.Methods We conducted grazing experiments with varying stock rates in a typical steppe of Nei Mongol,and investigated the changes in the activities and stoichiometric ratios of soil extracellular enzymes.Enzyme activities related to carbon(C),nitrogen(N),and phosphorus(P)cycling were analyzed,and a vector model was applied to determine soil nutrient limitations under different grazing intensities.Important findings 1)Soil hydrolase activities in the studied grassland ranged from 0 to 300 nmol·g–1·h–1,which is relatively low compared with the global averages.Grazing intensity significantly impacted the activities of soil enzymes,includingα-glucosidase,cellulose hydrolysis,xylosidase,β-d-cellubiosidase,β-1,4-N-acetylamino-glucosidase,glycosaminidase,leucine aminopeptidase,and acid phosphatase.The enzymeactivities peaked under moderate grazing and recommended grazing.2)The Standardized Major Axis(SMA)regression analysis revealed strong linear relationships between the enzyme activities associated with C,N,and Pcycling.The soil enzyme C:N:P stoichiometric ratio was 1:2.3:1.3,deviating from the global average 1:1:1.3)Thevector model based on soil enzyme stoichiometry indicated that the grasslands were co-limited by N and P,with Plimitation becoming more pronounced as grazing intensity increased in Nei Mongol.
作者
房凯
王迎新
黄建辉
段俊光
张琦
张倩
甘红豪
褚建民
FANG Kai;WANG Ying-Xin;HUANG Jian-Hui;DUAN Jun-Guang;ZHANG Qi;ZHANG Qian;GANHong-Hao;CHU Jian-Min(Research Institute of Forestry,Chinese Academy of Forestry,Beijing 100091,China;Coastal Forestry Research Center of the National Forestry and Grassland Administration,Beijing 100091,China;Research Institute of Ecological Conservation and Restoration,Chinese Academy of Forestry,Beijing 100091,China;State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,China National Botanical Garden,Beijing 100093,China;Experimental Center of Desert Forestry,Chinese Academy of Forestry,Dengkou,Nei Mongol 015200,China)
出处
《植物生态学报》
北大核心
2025年第1期7-18,共12页
Chinese Journal of Plant Ecology
基金
中国科学院战略性先导科技专项(A类)(XDA26020102)
中央级公益性科研院所基本科研业务费专项资金重点项目(CAFYBB2020ZB001)。
