用户名: 密码: 验证码:
The effect of nitrogen addition on community structure and productivity in grasslands: A meta-analysis
详细信息    查看全文
文摘
The ongoing increase in anthropogenic nitrogen (N) addition may have a substantial impact on grassland ecosystems. Understanding the dynamics of the productivity and community structure of grassland ecosystems following N addition is important. We conducted a meta-analysis of the data from 2516 quadrats described in 56 published N-addition studies and aimed to address these questions and further describe the productivity and community structure of grassland ecosystems in response to N addition in China. Our results showed the critical threshold for N-induced productivity loss to grassland was variable. In meadow steppe, when the range of N addition occurred at rates between 7.5 and 20 g N m−2 yr−1, the aboveground net primary production (ANPP) increased, and below this range, the biomass of the functional groups (forb, grass, and sedge) decreased. Furthermore, above the range, both productivity and structure were negatively related to the rate of N addition. The critical threshold for the N-induced changes in the productivity of the desert steppe was 10.5 g N m−2 yr−1, at which production increases with no reduction in diversity. Additionally, the increase in ANPP with N addition stabilizes above approximately 12 g N m−2 yr−1 in desert steppe, and the decrease in species richness with N addition stabilizes above approximately 11 g N m−2 yr−1. Thus, at approximately 11 g N m-2 yr−1, further N addition causes no increase in production and a clear reduction in diversity. Our results contribute to a better understanding of the consequences of future climate change in grassland ecosystems.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700