施肥和围封对青藏高原高寒草甸生产力稳定性的影响  

Effects of fertilization and enclosure on the temporal stability of above-ground net primary productivity in an alpine meadow of the Tibetan Plateau

作　　者：蚌绍豪 赵维 姚万万 周小龙 磨礼财 任正炜[1] BANG Shaohao;ZHAO Wei;YAO Wanwan;ZHOU Xiaolong;MO Licai;REN Zhengwei(College of Ecology,Lanzhou University,Lanzhou 730000,Gansu,China;School of Resources and Environmental Sciences/Key Laboratory of Oasis Ecology,Xinjiang University,Urumqi 830046,Xinjiang,China)

机构地区：[1]兰州大学生态学院,甘肃兰州730000 [2]新疆大学生态与环境学院/绿洲生态教育部重点实验室,新疆乌鲁木齐830000

出　　处：《草业科学》2024年第3期611-619,共9页Pratacultural Science

基　　金：国家自然科学基金项目(32060285);兰州大学学生创新创业行动计划项目(20220180013);兰州大学教学研究项目(广度和深度相统一的生态学野外实习)。

摘　　要：草地生产力稳定性不仅取决于时间序列上生产力及其变异性的相对变化幅度,而且也受到植物群落物种丰富度和异步性的影响。施肥与围封是高寒草甸生态系统中广泛使用的土地管理措施,其对生产力稳定性影响的生态学机制尚未得到一致认识。为此,本研究在青藏高原东缘高寒草甸中,以冬季放牧的草地群落为对照,在施肥(氮磷钾添加)处理的基础上,嵌套全年禁牧处理(围封和施肥+围封)进行为期4年的群落调查,旨在探究二者影响生产力稳定性变化的潜在机制。结果表明,围封对生产力稳定性的下降有显著影响,且主要受生产力及其变异性相对增加幅度的共同调节;同时还与减小的物种丰富度和异步性有关。另外,尽管结果并未发现施肥对生产力稳定性有显著影响,但施肥却导致物种丰富度减小和生产力增加。综上,本研究表明,冬季放牧有助于维持高寒草甸植物生产力稳定性;然而,一旦施加全年禁牧措施,无论施肥与否,都会加剧生产力稳定性的下降。因此,在未来高寒草甸生态系统修复和管理过程中必须慎重考虑不同土地利用方式影响草地物种多样性和生态系统功能的生态过程和途径。Changes in grassland utilization(i.e.,fertilization and enclosure)can influence the temporal stability of aboveground net primary productivity(ANPP)by altering ANPP and its temporal variability.In addition,changes in species richness and asynchrony can also drive changes in ANPP stability.Ecologists have focused on investigating the effects of fertilization or enclosure on ANPP stability via different ecological pathways in grassland ecosystems,but the mechanisms underlying these effects remain unclear.Here,we conducted a factorial experiment of fertilization(multiple additions of nitrogen,potassium,and phosphate)with all-year enclosure treatments(enclosure and fertilization plus enclosure)for four consecutive years in a grazed alpine meadow located in the Gannan region in the eastern part of the Tibetan Plateau.We aimed to investigate the mechanisms underlying the responses of ANPP stability to fertilization and enclosure.The results revealed that enclosure reduced ANPP stability,and this reduction was driven by the relative changes in ANPP and its variability and was closely associated with decrease in species richness and asynchrony.Furthermore,although no direct negative effects of fertilization on ANPP stability were observed,fertilization decreased the species richness and increased ANPP,which may translate into reductions in ANPP stability in the future.Our results indicated that winter grazing would contribute towards the maintenance of ANPP stability in an alpine meadow community,whereas year-round enclosure,regardless of fertilization,would deteriorate ANPP stability.Therefore,it is imperative to carefully evaluate the potential mechanisms influencing biodiversity and ecosystem functioning in grassland utilization and management in future research.

关 键 词：地上净初级第一生产力 时间稳定性 异步性 物种丰富度 施肥 围封 

分 类 号：S812[农业科学—草业科学]