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DOI	10.5194/hess-23-3917-2019
	The influence of water table depth on evapotranspiration in the Amazon arc of deforestation
	O'connor J.; Santos M.J.; Rebel K.T.; Dekker S.C.
发表日期	2019
ISSN	1027-5606
起始页码	3917
结束页码	3931
卷号	23 期号:9
英文摘要	The Amazon rainforest evapotranspiration (ET) flux provides climate-regulating and moisture-provisioning ecosystem services through a moisture recycling system. The dense complex canopy and deep root system creates an optimum structure to provide large ET fluxes to the atmosphere, forming the source of precipitation. Extensive land use and land cover change (LULCC) from forest to agriculture in the arc of deforestation breaks this moisture recycling system. Crops such as soybean are planted in large homogeneous monocultures and the maximum rooting depth of these crops is far shallower than forest. This difference in rooting depth is key as forests can access deep soil moisture and show no signs of water stress during the dry season, while in contrast crops are highly seasonal with a growing season dependent on rainfall. As access to soil moisture is a limiting factor in vegetation growth, we hypothesised that if crops could access soil moisture, they would undergo less water stress and therefore would have higher evapotranspiration rates than crops which could not access soil moisture. We combined remote-sensing data with modelled groundwater table depth (WTD) to assess whether vegetation in areas with a shallow WTD had higher ET than vegetation in deep WTD areas. We randomly selected areas of forest, savanna, and crop with deep and shallow WTD and examined whether they differ on MODIS Evapotranspiration (ET), Land Surface Temperature (LST), and Enhanced Vegetation Index (EVI), from 2001 to 2012, annually and during transition periods between the wet and dry seasons. As expected, we found no differences in ET, LST, and EVI for forest vegetation between deep and shallow WTD, which because of their deep roots could access water and maintain evapotranspiration for moisture recycling during the entire year. We found significantly higher ET and lower LST in shallow WTD crop areas than in deep WTD during the dry season transition, suggesting that crops in deep WTD undergo higher water stress than crops in shallow WTD areas. The differences found between crop in deep and shallow WTD, however, are of low significance with regards to the moisture recycling system, as the difference resulting from conversion of forest to crop has an overwhelming influence (ET in forest is ≈ 2mmd-1 higher than that in crops) and has the strongest impact on energy balance and ET. However, access to water during the transition between wet and dry seasons may positively influence growing season length in crop areas. © Author(s) 2019.
语种	英语
scopus关键词	Crops; Deforestation; Drought; Ecosystems; Evapotranspiration; Groundwater; Land surface temperature; Land use; Remote sensing; Soil moisture; Structural optimization; Vegetation; Deep soil moisture; Enhanced vegetation index; Groundwater table depth; Growing season lengths; Land use and land cover change; Optimum structures; Remote sensing data; Wet and dry seasons; Water recycling; deforestation; evapotranspiration; growing season; land cover; land use; NDVI; precipitation (climatology); rainfall; soil moisture; water table; Amazonia; Glycine max; White tip die-back phytoplasma
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159601
作者单位	O'connor, J., Copernicus Institute of Sustainable Development, Department Environmental Sciences, Utrecht University, Utrecht, Netherlands; Santos, M.J., University Research Priority Program in Global Change and Biodiversity and Department of Geography, University of Zürich, Zurich, Switzerland; Rebel, K.T., Copernicus Institute of Sustainable Development, Department Environmental Sciences, Utrecht University, Utrecht, Netherlands; Dekker, S.C., Copernicus Institute of Sustainable Development, Department Environmental Sciences, Utrecht University, Utrecht, Netherlands, Faculty of Management, Science and Technology, Open University, Heerlen, Netherlands
推荐引用方式 GB/T 7714	O'connor J.,Santos M.J.,Rebel K.T.,et al. The influence of water table depth on evapotranspiration in the Amazon arc of deforestation[J],2019,23(9).
APA	O'connor J.,Santos M.J.,Rebel K.T.,&Dekker S.C..(2019).The influence of water table depth on evapotranspiration in the Amazon arc of deforestation.Hydrology and Earth System Sciences,23(9).
MLA	O'connor J.,et al."The influence of water table depth on evapotranspiration in the Amazon arc of deforestation".Hydrology and Earth System Sciences 23.9(2019).