US EPA

3848393 

Journal Article 

Species-specific phenological responses to long-term nitrogen fertilization in an alpine meadow 

Yin, TF; Zheng, LL; Cao, GM; Song, MH; Yu, FH 

2017 

Yes 

Journal of Plant Ecology
ISSN: 1752-9921 

10 

2 

301-309 

English 

10.1093/jpe/rtw026 

WOS:000402091500005 

Aims



Long-term nitrogen (N) fertilization has profound impacts on community structure and ecosystem function, but little is known about its effects on plant phenology. Furthermore, no published study has examined effects of N chemical forms on plant phenology.



Methods



In an alpine meadow on the Tibetan Plateau, we monitored reproductive phenology of six common plant species after 8 years of fertilization with different N chemical forms (addition of 7.5 g N m(-2) yr(-1) in the forms of ammonium, nitrate and ammonium nitrate), with no N addition as the control.



Important Findings



Eight years of N fertilization affected plant reproductive phenology, and such effects depended on the species, N form and phenological phase. Fertilization with ammonium generally delayed, advanced or did not change flowering and fruiting phases of the alpine plants. Furthermore, fertilization with ammonium affected the temporal dispersion of reproductive phenology among the six species, especially among the late-flowering species. This could reduce the overlap of flowering and fruiting and increase phenological complementarity. Fertilization with nitrate only delayed the senescence phase of Elymus nutans, and fertilization with ammonium nitrate did not affect reproductive phenology of the six alpine plants. N fertilization with any form increased the overlap in senescence among the six species. We conclude that long-term N fertilization can cause shifts in plant phenology and such effects depend on N chemical forms. Our results also suggest that phenological complementarity could be a mechanism underlying resource partitioning and thus species coexistence in the face of changing N availability with different chemical forms. 

reproductive phenology; fertilization; nitrogen forms; temporal dispersion in phenology; alpine meadow