Spatial Patterns Of Dominant Populations And Beta Diversity Of The Community In A Secondary Evergreen Broad-Leved Forest In Wuyanling National Nature Reserve, East China

In 2011-2012, the Wuyanling 9 ha forest dynamics plot (FDP) was established according to the protocols of Center for Tropical Forest Sciences (CTFS) in Wuyanling National Nature Reserve, Zhejiang Province. Here we study the community composition (e.g., importance value of species) and structure (e.g., floristic composition, vertical structure, size-classed structure) of woody plants in this forest, and we ask the question of what mechanisms maintain its species diversity. To answer this question, we firstly analyzed the spatial patterns of dominant species in each vertical forest layer (i.e., canopy, subcanopy and understory). Then by using point pattern analysis, we studied density dependence and habitat heterogeneity effects on the spatial patterns of dominant species. Finally, we partitioned the environmental and spatial processes effects on the community composition (i.e., beta diversity). The main results and conclusions are as the following:1. There are 200 woody plant species belonging to 92 genera and 47 families in this forest. The dominant families are Fagaceae, Lauraceae, Theaceae, Aquifoliaceae, Ericaceae and Symplocaceae. There are slightly more tropical elements than temperate elements;2. DBH size-classed community structure is’L’shaped, indicates abundant regeneration. Population structures of dominant species showed various shapes, like reverse ’J’, skewness or wave, but no signs indicate population decline;3. Habitat heterogeneity shaped the spatial distributions of dominant species towards aggregated distribution patterns;4. After removing habitat heterogeneity effects using the random-labeling null model within case-control design, density dependence self-thinning effected on 10 in 12 (83.3%) examined dominant species, suggesting density dependence was prevalent in this forest;5. Self-thinning effect tended to decrease with advance of life stages of the examined species;6. Beta diversity decreased with the increase in grain size;7. Comparison of beta diversity of forests along a latitudinal gradient showed a clear decrease from the tropical to temperate forests;8. The results of beta diversity partitioning suggest that the diversity of this forest is shaped by both environmental control (12%) and neutral process (36%).Our findings indicate that density dependence, environmental control and neutral processes maintain the species diversity of this secondary subtropical broad-leaved forest.