Macaranga (Euphorbiaceae) myrmecophytes provide their partner ants (plant-ants) with hollow stems used as nesting spaces, as well as food bodies as food rewards. In return, they benefit from the anti-herbivore defense of the ants. The plants harbor not only ants but also specific honeydew-producing coccids, which live inside the ant nests in the hollow stems. Although the honeydews are fed by the plant-ants, their effect on the growth of plant-ant colonies is undetermined. In this study, we investigated how such myrmecophilous coccids, Coccus spp. affect the colony growth of plant-ants, Crematogaster spp. on the myrmecophytic species M. bancana. We compared the growth of plant-ant colonies on seedlings from which coccids were experimentally excluded with that on seedlings into which specific myrmecophilous coccids were experimentally introduced. Foundress queens in 14 of 16 coccid-excluded seedlings died by the time we dissected the seedlings 235-637 days after the seedlings were transplanted in a meshed nursery. In contrast, those on 12 of 17 coccid-introduced seedlings survived during that period, with the survival rate of queens differing significantly between treatments. This result suggests that the symbiotic coccids provide nutrients that facilitate the colony growth of plant-ants inhabiting Macaranga myrmecophytes.

抄録全体を表示

Indonesia has experienced severe tropical forest fires from a long time ago, mainly in El Niño years. However, previous studies showed that after 1997 forest and peat fires in Indonesia tend to occur every year in the dry season, even in non El Niño years. To clarify this recent pattern of incidence, we studied the fire situation in the Mega Rice Project (MRP) area, Central Kalimantan where large scale development of tropical swamp-forest has been carried out since 1996. To identify the causes of the recent severe peat fires, weather data for Palangkaraya from 1978 to 2007, hotspot data captured by the MODIS satellite, monthly Niño 3.4 sea surface temperature (SST) anomalies, and ground water level (GWL) data were analyzed. The results of the analysis clearly showed a relationship among the precipitation pattern of the dry season, GWL change, Niño 3.4 SST Anomalies, and fire occurrences. A pattern of low precipitation in the dry season decreased GWL and caused a peat fire peak in the middle of August when daily precipitation reached the minimum. These results suggest that large areas of bared peat in the MRP now has a high susceptibility to fire coupled with the precipitation pattern of the dry season.

抄録全体を表示

This paper studied the possibility and challenge of achieving sustainable rural finance by the Dayak Peoples‘ Credit Union (CU) in Indonesia’s Middle-Upper Mahakam region. CUs, “self-help”, “solidarity” and “self-governance” financial cooperatives, which were founded in 19th-century Germany, try to establish self-sustainable rural finance, but they do not operate according to neoclassical economics. The harmony of individualism and cooperative socialism is the key feature of CUs. CU operation is based on common bonds such as occupation, religion, ethnicity, and community relations to mitigate the threat of capitalism and provide for the economic security of small entrepreneurs and small farmers. The CU movement has been developing rapidly since democratization in Indonesia. Credit Union Petamai Urip (CUPU) was the first CU to start operating in the Middle-Upper Mahakam region. Having local people serve as employees and kolektors in the capacity of low-wage and voluntary workers helps reduce operating costs, absorbs large transaction costs, and solves the information asymmetry problem by using their local networks and making use of local employees ‘and kolektors’ efforts and sense of social responsibility to their communities. Even though CUPU faces difficulty owing to economic hardships in the Middle-Upper Mahakam region, it is the first microfinance institution (MFI) run by local people and has operated for a relatively long term in this region. Although this study focuses on only one CU in East Kalimantan, it suggests that ongoing expansion of the CU movement in Indonesia also has potential to contribute to sustainable rural finance development in other rural areas where existing MFIs such as banks and cooperatives supported by government do not work well or have not existed.

抄録全体を表示