Composition And Temporal Dynamics Of Litterfall And Seed Rain In An Evergreen Board-leaved Forest In Baishanzu National Natural Reserve

Study of litterfall and seed rain have been the main part of community ecology for years. Litterfall plays a crucial role in nutrient cycling in forest systems, while the seed rain is critical in forest regeneration and dynamics. The establishment of large-scale forest dynamics plots in the past several years has made the long-term monitoring in tropical forests possible, but similar studies in subtropical forests were few here in China. In this paper, the composition and temporal dynamics of litterfall and seed rain from 2009 to 2011 in Baishanzu 5 ha forest plot have been studied.From the analysis of the litterfall collected from the 50 collection stations in the plot, the letterfall of evergreen broad-leaved species accounts for more than 80% of the total litterfall, the fallen leaves of 9 dominant species occupies 86% of all withered leaves, and the except the Fagus lucida which is a deciduous tree, the remaining 8 dominant species are evergreen trees, this means the evergreen species plays a major role in the forest. The leaves takes up 88.83% of the total amount of all litterfall, that makes it the largest part in the litterfall. From the study of temporal dynamics of litterfall, we find there are two peaks in the litterfall falling, one is between April and June, and the other is from October to November, the litterfall of broken little branches, barks and others in litterfall is irregular. From the figures of temporal dynamics, the large or little peaks can be found in July to August each year, when the plot get interrupted most times every year.The amount and diversity of seed rain, to some extent, reflects fruiting status and the potential of the regeneration ability in the forest, since it can affect the forest regeneration process, community structure and species composition. From the analysis of the collecting seed rain from 2009 to 2011, there are 50 different species collected, with 30 species in flower, 42 species in fruit and 13 species in seed. Among these species, Schima superba、Symplocos stellaris、Lithocarpus brevicaudatus、Camelliar cuspidata、Rhododendron latoucheae和Cyclobalanopsis multinervis have the largest number or amount in the flowers collections; while the fruit and seeds of S. superba, C. multinervis, L. Brevicaudatus, F. lucida, C. cuspidate and Acer olivaceum are ranking top in all species which have their fruits or seeds appeared in the traps. The temporal dynamics shows that the peaks of flower, fruit and seed are in order, with the amount of flower peaks from June to August, the fruit in about October and the seed in December to the next January. From the analysis of temporal dynamics of flowers, fruits and seeds, these collections are different from their weight and the collected numbers, and the collections of fruits in 2010 are obviously larger than the collections in 2009 and 2011, which indicates the potential in-and-off year phenomenon of seed rains in the plot, and this phenomenon may due to the different climate conditions among the three years or due to the self-protection strategy from the animals in the forest by the species. At the same time, the temporal dynamics also display a small peak in June to August, when the typhoon and storm are usual during this time, which means that the seed rain is affected by the climate.The regeneration of forest is a continuous process, so it is necessary to study the seeds producing, seed dispersal, seed pool, seedlings as a whole. The study of the composition and temporal dynamics in Baishanzu plots gives a fundamental foundation to the further study of seed dispersal, forest dynamics and diversity.