Demographic effects of collecting rattan cane and their implications for sustainable harvesting
Abstract:Rattan Old World climbing palm is an extremely valuable nontimber forest product whose canes are gathered for both market and nonmarket uses. I evaluated the effects of harvesting commercial rattan Calamus zollingeri Becc. on genet survival and ramet demography in two primary forest sites near Lore Lindu National Park in Sulawesi Indonesia. I monitored 168 permanently marked C. zollingeri genets for 4 years and surveyed random transects for C. zollingeri genet and ramet populations and evidence of cane harvesting in 1996 and 2000. Cane harvesting had no significant effect on genet survival or mean ramet densities. However current cane extraction rates significantly reduced mean cane lengths and total available cane throughout the area during the study period. Based on observed genet and ramet populations and average cane growth rates of 1.4 m/year the sustained-yield harvesting potential of C. zollingeri is approximately 101 m and 56 m/ha/year in the two study sites. Although C. zollingeri exhibits life-history traits well suited to sustained-yield harvesting including production of multiple canes cane resprouting following harvest rapid cane growth and widespread abundance below 1100 m current harvest rates exceed growth and yield and supplies of cane are being depleted. Rattan harvesting is widespread in Lore Lindu National Park. Approximately 18% of the park (42000 ha) is likely subject to intensive and unsustainable extraction of C. zollingeri.