Detecting density dependence on tree survival in a deciduous broadleaved forest in Baotianman National Nature Reserve

It has been found that density dependence plays a crucial role in determination of species distribu- tion and coexistence, and the effect of negative density dependence also plays an important part among phy- logenetically related species. Based on two census datasets in 2009 and 2014 of the 1-ha deciduous broad- leaved forest plot in Baotianman National Nature Reserve, generalized linear mixed models (GLMMs) were used to examine the density dependence on individual survival of the top 11 species (with high important value) at different neighborhood scales and different DBH sizes (1 cm ≤ DBH< 5 cm, 5 cm ≤ DBH < 10 cm, DBH ≥ 10 cm). The results showed that (1) mean annual mortality and recruitment rate of indi- viduals (DBH ≥ 1 cm) were 5.85% and 0.27%, respectively; (2) survival rate of 5 tree species was nega- tively correlated with abundance or neighbor conspecific basal area; (3) density dependence and phylogenetic diversity exerted significant effects on survival of small individuals (at 5 m neighborhood scale), whereas no significant influence on medium trees. With increasing tree size, phylogenetic diversity exerted important ef- fect on large individuals at 7.5 m and 10 m neighborhood scales. In conclusion, density dependence and phy- logenetic diversity play different roles on tree survival at different life stages and neighborhood scales in the deciduous broad-leaved forest in Baotianman National Nature Reserve. ·研究报告·