Edge Effects On Liana Communities In A Natural Secondary Forest In Bawangling, Hainan Island

To assess the edge effects on liana communities,we choose two types of edges which differ in formation age,17 years and 13 years,respectively, in total 0.8 hm2 transects from forest edges to interior region in a 60-year old natural secondary tropical rain forest,Bawangling Nature Reserve, Hainan Island. Liana diversity,size structure,climbing mechanisms,vertical distribution and the relationship with trees were investigated in both edges. A total 3252 liana individuals belonging to 89 species in 36 plant families were recorded.Liana abundance decreases significantly with increasing distance from forest edge in both edges. Liana richness decreases with increasing distance from the edge in the 17-year old edge. Liana breast height area is not affected by forest edge. In the 13-year old edge,the proportion of liana individuals with DBH larger than lcm increases with the increase of distance from forest edge. Liana size structure is relatively stable in the 17-year old edge. Liana climbing mechanisms varies significantly in different distances to forest edge. Stem twiners dominates in both edge. Edge effects on liana community structures decline with increasing distance to forest edge and the influence depth enhances with edge age. The influence depth is 40-50m in the 17-year old edge and approximately 10m in the 13-year old edge.Tree area at breast height,mean area at breast height,mean height,mean brunch free bole height and number of seedlings are not affected by forest edge. Tree species composition decrease with increasing distance from the edge in both edges,edge effect on tree richness penetrate about 20-30m in the 17-year old edge and 10-20m in the 13-year old edge. In the 13-year old edge,tree abundance decrease with the increase of distance from forest edge. Tree size distribution does not show a certain trend towards edge. The older edge have higher tree and seedling abundance.In both edges,proportion of trees with lianas change with different distance to edge among tree size DBH1-5cm and 5-10cm, while trees with DBH>20cm in the 17-year old edge and trees DBH 10～20 cm in the 13-year old edge are not affected by forest edge. Frequency of liana infestigation decrease with increasing distance to edge. Number of trees with more than 3 lianas is the lowest and change significantly in the 17-year old edge,while number of tree with 1 liana is height and change significantly in the 13-year old edge. Lianas per tree decrease with increasing distance from edge in the 17-year old edge. Formation age of edge affect the number of lianas per tree,which decrease more sharply in the 17-year old edge.In the 17-year old edge,number of liana individuals in different height class decrease with the increase of distance from edge. Liana stem area at breast height in different height class change with the distance from edge in both edges. Canopy lianas have the lowest proportion but the highest contribution to area at breast height. Climbing guilds of lianas in 0-5m height class change with different distance to forest edge. Stem twiners dominate in each height class.In a word,liana diversity, vertical distribution and the relationship with trees (proportion of trees with lianas,frequency of liana infestigation and number of lianas per tree) change with the distance from forest edge. As the formation age growing,lianas respond differently to edges. The influence depth of edge is 40-50m in the 17-year old edge and approximately 10m in the 13-year old edge.