Effects Of Species Loss On Plant Flowering Phenology In The Tibetan Alpine Meadow

Phenology is an important factor reflecting biological rhythm and natural environment changes.Plant flowering phenology is an important trait,which can strongly affect the fitness and final reproduction of plants and reflect different growth strategies of plants.A large number of studies have focused the influence of abiotic factors(temperature,water,light,etc.)on flowering phenology,but few have systematically studied the influence of biotic factors such as species diversity on flowering phenology,especially species loss.Based on species removal,we intended to explore effects of species loss on flowering phenology.Since 2011,we have conducted species removal of functional groups in the Tibetan alpine meadow,including removal of graminoids,legumes,forbs,dominant Korbresia Capillifolia and two or three species within a functional group.We observed the flowering phenology of the remaining species in 2017 and 2018,and analyzed the variation of different flowering groups and functional groups.The results were as follows:(1)After removing Korbresia Capillifolia,for early flowering species,the first flowering data was delayed,the flowering end data was advanced,and flowering duration was shortened;the first flowering data was advanced after removing forbs.(2)After removing forbs,for mid flowering species,the first flowering data and flowering end data were both significantly delayed.(3)When forbs were removed,for the late flowering plants,the first flowering data was advanced and flowering duration was extended;When graminoids were removed,the flowering duration was shortened.(4)Regardless of species removal,the first flower data was advanced for leguminous plants.(5)After removing two or three for each functional group,the first flower data was advanced and the flowering duration was prolonged for graminoids.(6)After removing Korbresia Capillifolia,the first flowering data of sedges were delayed and the flowering duration was prolonged.(7)The first flowering data of the forbs were advanced after removingKobresia Capillifolia.(8)Species loss had a significant impact on the community microenvironment(aboveground temperature andtopsoil humidity),In some of the treatments,the microenvironment was associated with the phenological changes of flowering.The above results showed that species loss of different function groups significantly affected flowering phenology in the alpine meadow,which can improve the understanding of the consequences of species diversity loss and the important role of species diversity in maintaining the ecosystem function.