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Transpiration on the rebound in lowland Sumatra

Author:
Röll, A., Niu, F., Meijide, A., Ahongshangbam, J., Ehbrecht, M., Guillaume, T., Gunawan, D., Hardanto, A., Hendrayanto,, Hertel, D., Kotowska, M.M., Kreft, H., Kuzyakov, Y., Leuschner, C., Nomura, M., Polle, A., Rembold, K., Sahner, J., Seidel, D., Zemp, D.C., Knohl, A., Hölscher, D.
Source:
Agricultural and forest meteorology 2019 v.274 pp. 160-171
ISSN:
0168-1923
Subject:
Elaeis guineensis, agroforestry, humans, land cover, land use change, landscapes, lowlands, oils, plantations, rain forests, rubber, sap flow, soil degradation, soil properties, stand structure, transpiration, water shortages, Indonesia
Abstract:
Following large-scale conversion of rainforest, rubber and oil palm plantations dominate lowland Sumatra (Indonesia) and other parts of South East Asia today, with potentially far-reaching ecohydrological consequences. We assessed how such land-use change affects plant transpiration by sap flux measurements at 42 sites in selectively logged rainforests, agroforests and rubber and oil palm monoculture plantations in the lowlands of Sumatra. Site-to-site variability in stand-scale transpiration and tree-level water use were explained by stand structure, productivity, soil properties and plantation age. Along a land-use change trajectory forest-rubber-oil palm, time-averaged transpiration decreases by 43 ± 11% from forest to rubber monoculture plantations, but rebounds with conversion to smallholder oil palm plantations. We uncovered that particularly commercial, intensive oil palm cultivation leads to high transpiration (827 ± 77 mm yr−1), substantially surpassing rates at our forest sites (589 ± 52 mm yr−1). Compared to smallholder oil palm, land-use intensification leads to 1.7-times higher transpiration in commercial plantations. Combined with severe soil degradation, the high transpiration may cause periodical water scarcity for humans in oil palm-dominated landscapes. As oil palm is projected to further expand, severe shifts in water cycling after land-cover change and water scarcity due to land-use intensification may become more widespread.
Agid:
6393398