There is a debate about unmatched results between manipulative warming using constant warming rates every year(CW)and long-term observations warming affect temperature sensitivity of flowering phenology.This may be be...There is a debate about unmatched results between manipulative warming using constant warming rates every year(CW)and long-term observations warming affect temperature sensitivity of flowering phenology.This may be because long-term observations represent the actual yearly increase in temperature(i.e.a yearly stepwise warming rate per year,SW)which would differ from CW and their effects would be regulated by precipitation alteration.We conducted a warming experiment with CW(temperature increase by+1°C and sustained this elevated temperature for the duration of the study)and SW(temperature increase by+0.25°C progressively each year)with precipitation addition in an alpine grassland for four years.Our results showed that neither warming rate affected community flowering phenology.However,precipitation addition advanced onsets of flowering for early-spring flowering(ESF)and midsummer flowering(MSF)groups,and advanced the end date of flowering for ESF but delayed it for the MSF group.Therefore,flowering duration remained stable for the ESF group and prolonged for the MSF group,and further prolonging the flowering duration of the community.There were no interactions between warming rates and precipitation addition on the community’s flowering phenology.A severe drought in a year significantly decreased the maximal number of community flowers in the following year.Therefore,a change in precipitation has a greater effect than warming on the community flowering phenology in the semi-arid alpine grassland.展开更多
Temperature and precipitation are the main factors determining plant community succession and aboveground net primary productivity(ANPP)in natural grasslands.However,most climate manipulative experiments have mainly f...Temperature and precipitation are the main factors determining plant community succession and aboveground net primary productivity(ANPP)in natural grasslands.However,most climate manipulative experiments have mainly focused on their impacts in isolation,especially in alpine regions.Here we explored the relative effects and interaction of warming and precipitation alteration on succession and ANPP using a 7-year experiment involving warming with precipitation alteration(increase(IP)or decrease(DP))in precipitation relative to ambient precipitation(AP)on the Tibetan Plateau.Our results showed that warming and warm-wet conditions increased species richness,diversity index,height and cover of overall species.Conversely,decreasing precipitation reduced them,but increased S.purpurea and the rate of change in community composition.Importantly,warming mitigated the impacts of decreased precipitation on plant community composition,and the interactive effects of warming and altered precipitation on cover,height and plant ANPP varied with year and plant species.Generally,warming increased community ANPP through increases in forb ANPP or non-dominant species ANPP and biodiversity regardless of change in precipitation.However,decreased precipitation reduced community ANPP via decreases in the ANPP of sedges and forbs and biodiversity.Precipitation alteration affected the relationship between biodiversity and community ANPP regardless of warming(IP<AP<DP).Therefore,generally warming and decreased precipitation have opposite effects on ANPP in the alpine grassland,suggesting that warming mitigated the negative impacts of drought on the ANPP of the alpine grassland.展开更多
基金supported by grants from the National Natural Science Foundation of China(41731175 and 41988101)the Strategic Priority Research Program A of the Chinese Academy of Sciences(XDA20050101)+1 种基金the Joint Key Research Fund under a cooperative agreement between the National Natural Science Foundation of China(NSFC)and Tibet Autonomous Region(TAR)(U20A2005)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0608 and 2019QZKK0302).
文摘There is a debate about unmatched results between manipulative warming using constant warming rates every year(CW)and long-term observations warming affect temperature sensitivity of flowering phenology.This may be because long-term observations represent the actual yearly increase in temperature(i.e.a yearly stepwise warming rate per year,SW)which would differ from CW and their effects would be regulated by precipitation alteration.We conducted a warming experiment with CW(temperature increase by+1°C and sustained this elevated temperature for the duration of the study)and SW(temperature increase by+0.25°C progressively each year)with precipitation addition in an alpine grassland for four years.Our results showed that neither warming rate affected community flowering phenology.However,precipitation addition advanced onsets of flowering for early-spring flowering(ESF)and midsummer flowering(MSF)groups,and advanced the end date of flowering for ESF but delayed it for the MSF group.Therefore,flowering duration remained stable for the ESF group and prolonged for the MSF group,and further prolonging the flowering duration of the community.There were no interactions between warming rates and precipitation addition on the community’s flowering phenology.A severe drought in a year significantly decreased the maximal number of community flowers in the following year.Therefore,a change in precipitation has a greater effect than warming on the community flowering phenology in the semi-arid alpine grassland.
基金supported by the Projects of Naqu Science and Technology Bureau of Xizang Autonomous Region(Grant No.NQKJ2023-03)the National Natural Science Foundation of China(Grant Nos.42230504 and 32201358)+1 种基金the Joint Key Research Fund(Grant No.U20A2005)under a cooperative agreement with the National Natural Science Foundation of China(NSFC)Ali Science and Technology Bureau of Xizang Autonomous Region(Grant No.QYXTZX-AL2022-05)。
文摘Temperature and precipitation are the main factors determining plant community succession and aboveground net primary productivity(ANPP)in natural grasslands.However,most climate manipulative experiments have mainly focused on their impacts in isolation,especially in alpine regions.Here we explored the relative effects and interaction of warming and precipitation alteration on succession and ANPP using a 7-year experiment involving warming with precipitation alteration(increase(IP)or decrease(DP))in precipitation relative to ambient precipitation(AP)on the Tibetan Plateau.Our results showed that warming and warm-wet conditions increased species richness,diversity index,height and cover of overall species.Conversely,decreasing precipitation reduced them,but increased S.purpurea and the rate of change in community composition.Importantly,warming mitigated the impacts of decreased precipitation on plant community composition,and the interactive effects of warming and altered precipitation on cover,height and plant ANPP varied with year and plant species.Generally,warming increased community ANPP through increases in forb ANPP or non-dominant species ANPP and biodiversity regardless of change in precipitation.However,decreased precipitation reduced community ANPP via decreases in the ANPP of sedges and forbs and biodiversity.Precipitation alteration affected the relationship between biodiversity and community ANPP regardless of warming(IP<AP<DP).Therefore,generally warming and decreased precipitation have opposite effects on ANPP in the alpine grassland,suggesting that warming mitigated the negative impacts of drought on the ANPP of the alpine grassland.
