氮和磷添加对草原群落特征及有关生态过程的影响

Effects of Nitrogen and Phosphorus Additions on Plant Community Characteristics and Related Ecological Processes

该文系统综述了氮、磷添加对天然草原生产力、植物多样性以及氮利用策略、根系周转等有关生态过程的影响。多数研究表明氮添加提高了温性草原的生产力、降低了其物种多样性,但氮添加对高寒草甸生产力的影响不尽相同。单独磷添加对物种生产力和丰富度无显著性影响;氮、磷同时添加对于提高生产力存在互作效应。另外,同一功能群植物在不同生态系统中对氮、磷添加响应也不同。当土壤氮含量发生变化时,不同植物对氮的利用形态存在明显的生态位分离,进而影响生产力和物种组成。典型草原和高寒草甸植物叶片氮、磷含量以及回收量对氮、磷添加的响应结果并不一致。氮添加能够提高细根的寿命,磷添加能够提高地下根系的生物量,而氮、磷同时添加对生产力尤其是细根形态的变化和周转产生显著影响。但目前的研究多以野外观测为主,缺乏长期生态过程和机理的研究,尤其是关于地下生态过程的研究。另外磷添加如何影响主要植物和群落对氮利用形态的生态位分离等过程和机理的研究有待进一步加强。

The paper expounds the effects of nitrogen（N） and phosphorous（P） on the productivity,plant species diversity,and related ecological processes,such as N utilization strategy and root turnover of natural grasslands.Most studies have shown that N addition could improve productivity and reduce species diversity of temperate grassland,while it has different effects on alpine meadow productivity. Individual P addition has no significant effect on species productivity and richness,but addition of N and P has an interaction effect on plant production. Moreover,the same functional group of plant has different responses to N and P addition in different grassland ecosystems. Different plants have obvious ecological niche separation in the use form of N when the content of soil N changes,which can affect productivity and species composition. The responses of leaf N and P content and their recovery to N and P addition were different between typical grassland and alpine meadow. N addition could improve the longevity of fine root,and P addition could improve the biomass of underground root,but the addition of N and P has a significant effect on the productivity,especially the morphology change of fine root and their turnover. However,the present study mainly focuses on field observations,and lack of long-term research about the ecological process and mechanism,especially the study on the belowground eco-process. Furthermore,the research needs to be further strengthened,which how P addition would influence the processes and mechanism of the ecological niche sepa-ration of the dominant plants and communities in the utilization form of N.