Regeneration and development of native plant species in restored mountain forests, Hainan Island, China

Abstract

Natural regeneration was studied at 7-year-old native species regeneration sites on abandoned lands in central mountain areas of Hainan Island, off China's southern coast. Using linear sampling, 7 belt transects (each 5 m in width, with a cumulative length of 2000 m) were established and then subdivided into 400 plots (5 m × 5 m). Plant regeneration was surveyed on each plot. For each woody species, the life stage, mature height, dispersal mode, and successional status were assessed. The regenerating woody community at the sites was found to be species-rich, with 40 species identified. However, the community was dominated by a subset of secondary forest pioneer species, such as Liquidambar formosana, Aporosa chinensis, and Lannea grandis, whereas a number of prominent primary forest species, such as Castanopsis hainanensis and Machilus chinensis, were almost completely absent. Clustering analysis divided the 40 species into different functional groups: those with a primarily economic function, a primarily ecological function, or both. A schematic illustration of the distribution of the 40 vegetation species over a larger area was created to show the functions and dominant status of species in the plots. This diagram can provide a clear reference for practical planning of forest rehabilitation. The results indicate that self-restoration has been successful in promoting native forest development to a certain extent, but that there is a need for management interventions in restoring vegetation species diversity and functional complexity, especially where natural successional processes are hampered by artificial or natural disturbances.