Background:Understanding the response of the plant community to increasing nitrogen(N)and phosphorus(P)inputs is helpful for managing and protecting grassland ecosystems in semiarid areas.However,information about dif...Background:Understanding the response of the plant community to increasing nitrogen(N)and phosphorus(P)inputs is helpful for managing and protecting grassland ecosystems in semiarid areas.However,information about different types of steppe responses to N and P availability in semiarid grasslands is limited.In 2017-2018,two field experiments were conducted with six levels of N(from 5 to 30 g N m^(−2)yr^(−1))and P(from 2.5 g to 15 g P m^(−2)yr^(−1))additions in three different temperate steppes,including meadow steppe(MS),typical steppe(TS),and desert steppe(DS),in northern China to study the effects of these addition rates on community biomass and diversity.Results:Our results showed that plant biomass and diversity in the three steppe types in Inner Mongolia responded differently to elevated N and P inputs.Increasing P promoted aboveground and belowground biomass more than increasing N in the three temperate steppes.Short-term N and P additions reduced plant diversity to some extent,with the most pronounced decreases in MS and DS.It is noteworthy that there were response thresholds for plant diversity and biomass in response to N and P inputs in different steppe types(e.g.,10 g P m^(−2)yr^(−1)).Furthermore,redundancy analysis and stepwise regression analysis revealed that changes in soil properties induced by nutrient addition and climate conditions jointly regulated changes in vegetation biomass and diversity.Conclusions:The plant biomass and diversity of three steppe types in Inner Mongolia respond divergently to elevated N and P inputs.Our results indicate that regional differences in climate and soil substrate conditions may jointly contribute to the divergent responses of plant biomass and diversity to short-term N and P addition.Our analyses provide new insights into managing and protecting grassland ecosystems.Considering that the effects of nutrient addition on plant diversity and productivity may have increasing effects over time,studies on long-term in situ nutrient addition are necessary.展开更多
基金supported by the National Key Research and Development Program of China(2016YFA0600801).
文摘Background:Understanding the response of the plant community to increasing nitrogen(N)and phosphorus(P)inputs is helpful for managing and protecting grassland ecosystems in semiarid areas.However,information about different types of steppe responses to N and P availability in semiarid grasslands is limited.In 2017-2018,two field experiments were conducted with six levels of N(from 5 to 30 g N m^(−2)yr^(−1))and P(from 2.5 g to 15 g P m^(−2)yr^(−1))additions in three different temperate steppes,including meadow steppe(MS),typical steppe(TS),and desert steppe(DS),in northern China to study the effects of these addition rates on community biomass and diversity.Results:Our results showed that plant biomass and diversity in the three steppe types in Inner Mongolia responded differently to elevated N and P inputs.Increasing P promoted aboveground and belowground biomass more than increasing N in the three temperate steppes.Short-term N and P additions reduced plant diversity to some extent,with the most pronounced decreases in MS and DS.It is noteworthy that there were response thresholds for plant diversity and biomass in response to N and P inputs in different steppe types(e.g.,10 g P m^(−2)yr^(−1)).Furthermore,redundancy analysis and stepwise regression analysis revealed that changes in soil properties induced by nutrient addition and climate conditions jointly regulated changes in vegetation biomass and diversity.Conclusions:The plant biomass and diversity of three steppe types in Inner Mongolia respond divergently to elevated N and P inputs.Our results indicate that regional differences in climate and soil substrate conditions may jointly contribute to the divergent responses of plant biomass and diversity to short-term N and P addition.Our analyses provide new insights into managing and protecting grassland ecosystems.Considering that the effects of nutrient addition on plant diversity and productivity may have increasing effects over time,studies on long-term in situ nutrient addition are necessary.
