Drought effects on soil carbon dioxide efflux in two ecosystems in Central Sulawesi, Indonesia

摘要: Drought response on soil CO2 efflux and production dynamics were examined in two tropical ecosystems central Sulawesi, Indonesia. Large-scale throughfall displacement roofs built a cacao (Theobroma cacao) / Gliricidia sepium agroforestry plantation (560 m.a.s.l.) an undisturbed sub-montane rainforest (1,050 to simulate drought conditions. At each site, ecosystem responses from three roof plots compared control plots. Soil was measured spatially at the surface vertically within profile 2.5 m depth every weeks. 1. The simulated consisted of one month baseline evaluation phase, 13 months five rewetting phase. During phase experiment decreased by 13% comparison control. mild is attributed reasons. First, peaked intermediate moisture contents, but low when conditions became dry (in induced plots) very wet plots). This means that respiration differences between may have been masked concurrently Secondly, localized. some measurement chamber sites (n = 11) effects pronounced: as levels decreased. other 7) however, there no evident effect emissions. highest base tree stems with distance radiating outwards. Overall, had neutral effect: decreases emissions during period compensated for rebounded surpassed 2. half 24.5 four In contrast agroforest, sub montane experienced severe decrease production. Here, average 39 % period. moisture, main variable controlling CO2, exhibited strong positive linear relationship (R2 0.72). A observed. first which lasted nine months, leaf litter declined did 30 70 cm depth. second (the next 16 months) intensified further belowground heterotrophic autotrophic sources all depths. Leaf remained negligible. Recuperation after slow this not rebound plot levels. ecosystem, resulted reduction overall emission.