| Global warming is becoming more and more serious and leads to changes in global precipitation patterns.These changes have seriously affected the structure and function of terrestrial ecosystems,and feedback climate change.Plant phenology,as a sensor of plants to climate change,is very sensitive to climate change.A large number of studies have shown that changes in temperature and precipitation will significantly affect the occurrence time of phenological stages such as greening,flowering,fruiting,and coloring time,as well as the length of the growing season.However,the impact of different magnitude of climate change in different time(e.g.growing season aand non-growing season)on plant phenology is still unclear.It poses a huge challenge to the prediction of the response and feedback of terrestrial ecosystem structure and function to climate change.Therefore,this study selected typical grassland in northern China as the object,measured the changes of microclimate and plant functional traits,to quantitatively distinguished the effected of climate warming and elevated precipitation in the non-growing season and the growing season on the starting time,ending time and duration of each plant phenological stage in the ecosystem,and discussed the response mechanism of plant phenology to climate change.The main results were as follows:Non-growing season warming only advanced the ending of the growing season(EGS)in 2020 by2.0 days,but did not significantly affect the beginning of the growing season(BGS)and the length of the growing season(LGS).Non-growth season warming treatment had little impact on plant reproductive phenology,and only the flowering time and fruiting time of a few species were changed,such as delaying the first flowering date and the end of fruiting time of Pocaxia ruthenia.The first flowering dates of Chamaerhodos erecta in 2019 and Lespedeza bicolor in 2020 have been advanced.However,non-growing season warming had no significant effect on the reproductive phenology of most species.Growing season warming did not affect BGS and EGS in 2019,but postponed the EGS in 2020 and extended the LGS in 2020.Growth season warming advanced the the flowering time and fruiting time of most species,and delayed the end of fruiting time for Lepaedera bicolor,Agropyron cristatum and Stipa krylovii in 2020,extended the flowering duration of of Pocockia ruthenia,Lespedeza bicolor,Agropyron cristatum and the fruiting duration of most species.Non-growing season precipitation addition significantly affected the phenology of growing season,but the effect showed significant inter-annual variation.In 2019,non-growing season precipitation addition delayed BGS and EGS by 6.3 days and 1.9 days,respectively,and shortened LGS by 4.4 days;However,non-growing season precipitation addition in 2020 advanced BGS by 11.9 days,delayed EGS by 3.1 days and prolonged LGS by 15.0 days.There was no significant effect on the first flowering dates of the species investigated by non-growing season precipitation addition;but advanced the last flowering date of Chamaerhodos erecta in 2019,Ixeridium graminifolium and Agropyron cristatum in 2020;shortened the the flowering duration of Pocockia ruthenia(3.5 days),Chamaerhodos erecta(2.9 days),and Agropyron cristatum(3.0 days)in 2020;And delayed fruiting time of a few species.Growing season precipitation addition had no significant effect on EGS,it significantly delayed BGS and significantly shortened LGS in 2019;But advanced the BGS and extended the LGS in 2020.Growing season precipitation addition advanced the flowering and fruiting time of some species,the flowering duration of Potentilla tanacetifolia in 2019 and Chamaerhodos erecta and Potentilla tanacetifolia in 2020 were Prolonged.However,growing season precipltation addition shortened the floweing and fruiting duration of Pocockia ruthenia in 2019.There was a significant interaction between growing season warming and non-growing season precipitation addition.Without the precipitation addition in non-growing season,growing season warming significantly advanced BGS by 5.5 days,delayed EGS by 3.2 days,and prolonged LGS by 8.7 days.However,under the background of non-growing season precipitation addition,growing season warming delayed BGS by 4.1 days,advanced EGS by 1.2 days,and shortened LGS by 5.3 days.Non-growing season warming and non-growing season precipitation addition had significant interaction with BGS and EGS.Without the addition of precipitation in non-growing season,Without the addition of precipitation in non-growing season,non-growing season warming delayed BGS by 2.2 days,but had no significant effect on EGS.Under the background of non-growing season precipitation addition,non-growing season warming advanced BGS and EGS by 3.5 days and 2.9 days,respectively.In addition,there were also significant interaction effects among different factors on some reproductive phenologies,but the pattern of such interaction was not consistent with species.The plant height of most species has a significant correlation with the reproduction phenology.The first flowering time of Potentilla tanacetifolia,Pocockia ruthenia and Lespedeza bicolor was negatively correlated with plant height,while there was a positive correlation between the plant height and the end of fruiting date of Pocockia ruthenia and Lespedeza bicolor.The specific leaf area of Artemisia frigida was positively correlated with the end of fruiting date.The specific leaf area of other species had no significant correlation with other plant phenology index.In conclusion,this study expounds the response of the starting time,ending time and time distribution of typical grassland plants in Inner Mongolia to the warming and precipitation addition of nongrowth season and growth season,and found that precipitation changes mainly affect the starting time and ending time of the the growing season nutrition phenology,while warming mainly affects the reproductive phenology such as flowering time and fruiting time.In addition,the temperature and precipitation changes in different seasons have interactive effects on the plant phenology.These results suggest that both temperature and precipitation should be considered in the study of climate change on plant phenology,and the differences and interactions between temperature and precipitation changes in different seasons should be considered in the regulation of plant phenology.These results can provide partial data support for the study of terrestrial ecosystem response to climate change. |
PDF Full Text Request