The turnover dynamics of woody plants in a tropical lowland rain forest during recovery following anthropogenic disturbances.

An important indicator of forest dynamics is the forest community turnover rate, which was defined as the relative change in a variable of interest (e.g., basal area or stem abundance) to its maximum or total in the community over a certain period. Community turnover dynamics in part explain the community assembly process and give insights for understanding forest ecosystem functions. Here, we assessed how anthropogenic disturbances (shifting cultivation, clear cutting) affect turnover relative to old growth forests in a tropical lowland rainforest. Using two censuses over 5 years of twelve 1-ha forest dynamics plots (FDPs), we compared turnover dynamics of woody plant, then analyzed the influencing factors. We found that community turnover dynamics of FDPs that experienced shifting cultivation were significantly higher than those experienced clear cutting or no disturbance, but little difference between clear cutting and no disturbance. Stem mortality and relative growth rates were the highest contributors to stem and basal area turnover dynamics of woody plants, respectively. Both stem and turnover dynamics of woody plants were more consistent by the dynamics of trees (DBH≥5 cm). Canopy openness, as the most important drivers, was positively correlated with turnover rates, while soil available potassium and elevation were negatively correlated with turnover rates. We highlight the long-term impacts of major anthropogenic disturbances on tropical natural forests. Different conservation and restoration strategies should be adopted for tropical natural forests experienced different disturbance types.