关键词: 土地利用变化, 土地利用结构, 相对生态价值, 生态系统, 区域生态健康

Abstract: This paper studied the effects of rodents on the seed predation and dispersal of Castanopsis fargesii in Tiantong Mountain,a National Forest Park in Ningbo City of Zhejiang Province.In this Mountain,evergreen broadleaved forest is the major forest type,while C.fargesii is the dominant species.For seed release,five transects are located in three types of habitats: three in evergreen broad-leaved forest,and other two in Pinus massoniana forest and shrub land,respectively.The results showed that rodents Niviventer confucianus and Niviventer fulvescens were the main seed predators.The loss rate of C.fargesii seed was high during the beginning of observation period,and then decreased gradually.The daily seed disappearance rate (DSDR) varied in different habitats,which was the highest (7.54%) in shrub land,and the lowest (4.47%) in evergreen broad-leaved forest.Among the lost seeds,three categories of their fate were defined: (1) the seeds were consumed by rodents,and the fragments of the seeds were within the tags; (2) the seeds were cut from the tags by rodents,and their fate was unknown; (3) both the seed and the tag disappeared.The proportion of the three categories in these habitats was differed.In shrub land,the third category was the highest (97.77%),while at the second transect of evergreen broad-leaved forest,it was the lowest (8.91%).The difference was related to the vegetation composition and density in the habitats.The dispersal distance of the seeds by rodents was quite short,with the maximum of 12.7 m.

Key words: Land use change, Land use structure, Relative ecological value, Ecosystem, Regional ecological health