Rodents as the Key Predators of Ground Seeds of Quercus liaotungensis in Xiaolongmen Forestry Centre,Beijing

The seed deposition pattern created by seed dispersers is important for plant,and ultimately may influence the regeneration of a plant species.In this study,a declining Chinese endemic plant,Quercus liaotungensis,was studied in Xiaolongmen Forestry Centre，a Nation Park of Beijing from Sept.to Oct.in 2000.Seeds post-dispersal experiments of Q.liaotungensis were conducted with four different treatments (four different kinds of predators:Invertebrates,Invertebrates+rodents,all predators,and all predators with litter covering) in two plots.Sound and invalid seeds were used in 40 treatments;and totally 800 (sound and invalid seeds were 400 respectively) seeds were set in two plots.All of treatments were investigated 9 times during the period of field work.In the two plots,no seeds were moved in all treatment 1.The difference of dispersal seeds was no significant between all treatment 2 (rodents+invertebrates) and all treatment 3 (all predators) (P>0.05);but the difference of seed dispersal was significant between in all treatment 2 and treatment 4,so did treatment 3 and treatment 4.The differences between sound seeds dispersal and invalid seeds dispersal were significant in all treatment 2 of two plots (Plot 1:t=2.407,P<0.05;Plot 2:t=2.65,P<0.05),so did all treatment 3 of two plots (t=3.209,P<0.05;t=3.029,P<0.05).Total gnawing of invalid seeds were much more than those of sound seeds in two plots (χ2=14.75,P<0.05;χ2=9.85,P<0.05).All of the results confirmed that the rodents in the area，particularly Apodemus peninsulae (74.4% of the community),were the principal post-dispersal predators;and indicated that the microenvironment could affect the speed of seed removal;and showed that the invertebrates and birds had not affection on the dispersal of ground seeds；and indicated that rodents were preferred to predate sound seeds and might judge the quality of the oaks.