| Affiliation: | (1) Institute of Pacific Islands Forestry, USDA Forest Service, Pacific Southwest Research Station, 1151 Punchbowl Street, 96813 Honolulu, Hawaii, USA;(2) Present address: Natural Resource Ecology Laboratory, Colorado State University, 80523 Ft. Collins, Colorado, USA |
| Abstract: | Taro is a staple crop that is often grown in wetlands throughout the Indo-Pacific, but the long-term impacts of its cultivation on wetland ecosystem functions are unknown. The objective of this study was to determine how cultivating taro affects carbon cycling by comparing key pathways in a forested peatland and an adjacent cultivated taro patch. Leaves decomposed rapidly at both sites with roughly 73% remaining after 2 weeks, 53% after 8 weeks, 38% after 17 weeks, and 17% after 36 weeks. Root decomposition proceeded much more slowly with roughly 93% remaining after 2 weeks, 80% after 8 weeks, 71% after 17 weeks, and 66% after 36 weeks. Annual litterfall was 1181 g m–2 year–1 and 849 g m–2 year–1 for the forested and cultivated sites, respectively. For the two sites combined, litterfall consisted of 78% leaves, 10% reproductive material, 3% branches, and 9% miscellaneous material. Fine root biomass was greater in the forested site than the cultivated site, averaging 205 g m–2 and 34 g m–2, respectively. Fine root production was much greater in the forested than the cultivated site, averaging 226 g C m–2 year–1 and 48 g C m–2 year–1, respectively. Soil respiration averaged 99 mg C m–2 h–1 and 55 mg C m–2 h–1 at the forested and cultivated sites, respectively. We found that the major change to carbon fluxes in the cultivated site was less carbon was entering the peatland, particularly less root production. Alterations to the carbon cycle caused by cultivation would probably not be permanent, because taro patches are periodically abandoned and allowed to regenerate naturally. |
