Population structure and distribution pattern of endangered species, Dillenia pentagyna, in Indonesian natural reserve forest

Abstract

Regeneration strategy of endangered species is crucial for maintaining ecosystem sustainability in its endemic habitat. Dillenia pentagyna is a deciduous tree species with many potential benefits for medical use, silkworms’ fodder, and furniture, and is considered as an endangered tree species in Indonesia due to over exploitation in 1980s. The species is an important asset for Gunung Abang Natural Reserve Forest (GANRF) due to essential historical functions for flora, fauna, and local communities. We conducted an initial research to observe the population structure and distribution pattern of D.pentagyna in its native habitat to understand the growth- and population behavior. Using a random sampling method, we built 157 plots to identify the number of seedlings, saplings, poles, and trees followed by measurement of height and diameter-breast-height. We only found fifteen poles, six saplings, five trees, and no seedlings in the plots with dominant distribution in the center of GANRF area. The distribution pattern was random according to Morisita index (Iδ= 0.011 equal to 0), which explains that D.pentagyna grows randomly in nature independent to canopy gaps and slopes. Findings suggested that low population needs to be recovered by seedling initiation growth in the nursery before sowing in the field to avoid high mortality.