Temporal And Spatial Variation Of Seed Rain In A Broad-Leaved Evergreen Forest In Tiantong,Zhejiang Province,Eastern China

spatial and temporal variation of seed rain shows the reproductive and dispersal ability of the plant,which is very important to the community recruitment and the dynamic of the community.In this paper,the seed rain data is collected from 187 seed rain collectors which were equably placed in a 20 hectares evergreen broad-leaved forest plot in Zhejiang Tiantong,we collected seeds from October 2012 to September 2016 and 96,and we collected seeds every half a month.Firstly,the seasonal dynamics and interannual variability of seed rain in the community and population level were analyzed.Then,we constructed a generalized linear model by combining the biological and environmental factors.We used stepwise regression to look for the factors which affect the spatial variation of seed rain.The main conclusions are as follows:1)From October 2012 to September 2016,194056 seeds were collected from the plot,which are belonging to 83 species,56 genus and 30 families,and the density of seed rain was 519 No·m-2·a-1.Among them,the seeds of the theaceae plant are more,accounting for more than 50%of the total.The number of seeds of some deciduous tree species is also relatively high,such as Liquidambar formosana,Acer pubinerve,Carpinus viminea,Choerospondias axillaris and so on.2)At the community level,there was a significant seasonal dynamic of seed rain,which shows a single peak type,and its peak appeared in October to November.However,at the population level,the seasonal dynamics is not showed obviously.Because the productive phase is different among species.Meanwhile,the period from fruiting to dispersal is longer than 3 months among the mostly species.3)In the four years,the seed rain of the whole plot showed a certain phenomenon of mast seeding.In the autumn of 2013 and 2014,there were two peaks of seed rain’s number.However,at the population level,the phenomenon of mast seeding is obvious,the law of the mast seeding of species is different,1.mast seeding occurring every other year,2.just a peak in 4 years,3.no obvious mast seeding in 4 years.4)Compared with the temporal variation of seed rain,the spatial variation of seed rain is larger,and the spatial variation is mainly showed in the spatial distribution range and the abundance distribution pattern of seed rain.Using the stepwise regression analysis,we found that the spatial distribution pattern of the parent plant is the most important influencing factor affecting the spatial distribution of the seed rain,and the effect on the abundance distribution pattern of the seed rain is relatively weak,and the environmental factor is the important affecting factors of the abundance distribution pattern.In conclusion,in the community level,the seed rain of broad-leaved forest has the obvious seasonal dynamics in Tiantong plot,the peak usually appears in the autumn.The phenomenon of mast seeding is mainly showed in the population level,mast seeding is usually occurring every other year.In addition,the spatial distribution range of seed rain is mainly affected by the distribution of parent trees,and its abundance pattern is influenced by environmental factors.