Study On Flower Phenology And Plant Traits Of Alpine Meadow Communities In The Eastern Qinghai-Tibet Plateau

Phenology is the study of the periodic variation of plants, animals and environmental conditions in nature. Alpine meadow community in Maqu County, Gannan Tibetan Autonomous Prefecture, is one of the important parts of grassland ecosystem on the Qinghai Tibet Plateau. It has important significance for the study of the relationship between plant and plant traits. Through the research on the plant phenology of alpine meadow, which can provide basic data and background for climate change(global warming), this work has a very important practical significance.This study based upon the observation data on the flowering phenology in the growth season of 2014 and 2015,the environmental factors recorded through field work, the paper attempts to probe into the flowering phenological patterns and relationships among vatious phenological parameters of the plant community in different habitats(Alpine swamp meadow and Alpine typical meadow) in eastern Qinghai-Tibetan Plateau and further explores the possible ecological adaption between the factors mentioned above and the species coexistence of the plant community. The results indicate that :(1) There exists obvious differences between the community flowering phenology of alpine swamp meadow and alpine typical meadow, expressed in that the initial date, peak date and duration of flowering are different among different species in the same habitat and the same species in different habitats.In alpine swamp meadows, species begin to enter their flowering in the middle of April, blossom into the peak in the middle of July, and end in the middle of September.While the flowering phenology of species in alpine typical meadow was a little later, as in late April began to flowering, flowering peak in late July, and gradually end in late September.The flowering period of species throughout the whole growing season, lasted for more than five months;(2) Both in the same habitat and different habitats, the flowering period of most species was concentrated from the middle of July to the middle of August, this is also the period of maximum temperature and moisture in a year, illustrated that environmental factor is the main influence factor of the alpine meadow plant community’s flowering phenology.Soil temperature(ST) in alpine typical meadow was significantly higher, the average temperature is 2.3 ℃ higher than in the alpine swamp meadow, while the soil water content(SWC) in alpine swamp meadow was 5.7% higher than another.Cyperaceae species such as Scirpus pumilus and Kobresia capillifolia,their greenup required lower accumulated temperature, so their beginning of flowering period in alpine swamp meadows is earlier than in alpine typical meadow, while gramineae species such as Poa pratensisneed,Poa poophagorum and Agrostis gigantea need higher accumulated temperature, their flowering time is characterized by alpine typical meadow predated alpine swamp meadow.Temperature rise significantly affects the flowering phenology of plant community;(3) The flowering duration was negatively correlated with the peak floweri ng date in both alpine typical meadow and swamp meadow, that is to say, the species which flowering earlier always has longer flowering duration,and vice versa.This correlation relationship between them codetermine the flowering phenology pattern in plant community of alpine meadow;(4) We checked the peak flowering period of 17 families in alpine swamp meadow and 15 in typical meadow,the results show a random distribution.This suggests that the phenological niche differentiation does not play a decisive role in the maintaining of species diversity in plant community, or just of little help;(5) Either in plant community of alpine swamp meadow or in alpine typical meadow, the flowering phenology is significantly affected by the plant height and seed size, followed by the plant biomass, while leaf area and plant flowering phenology found no correlation.