Different Hydrologic Responses to Vegetation Greening between Water-limited and Energy-limited Basins
Abstract
Vegetation greening has been reported at regional and continental scales on the basis of forest inventory and satellite measurements. Large areas of vegetation greening have been observed in China due to the implementation of country-wide ecological protection and reforestation programs since the late 1990s. Investigation on how vegetation greening affects hydrologic cycle is an important topic for hydrologic research. In this study, two typical greening regions with different climatic conditions, namely the Loess Plateau with relatively dry climatic condition and the largest freshwater lake in China (Poyang Lake) with humid climatic condition, were selected to investigate hydrologic responses to vegetation greening. Results show that large-scale greening in the Poyang Lake basin did not cause significant water reduction, while greening in the Loess Plateau did lead to a significant decrease in streamflow. Vegetation greening allows more precipitation to be intercepted by the vegetation canopy and to be infiltrated into soil. In the Loess Plateau, those increased intercepted and infiltrated water quickly return to the atmosphere through evaporation (Ea) because of the water-limited condition, leading to the decrease in streamflow. In the Poyang Lake basin, however, the increased intercepted and infiltrated water did not increase Ea, because Ea is constrained by potential evaporation (Ep) due to the energy-limited condition. The increased intercepted and infiltrated water enhanced groundwater recharge and thus baseflow in the Poyang Lake basin. The findings highlight that hydrologic responses to vegetation greening greatly depend on regional climatic conditions, which is inconsistent with the widely held perception of the trade-off relationship between vegetation greening and water resources. These results can benefit future ecological protection and reforestation programs and water resource management worldwide.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMGC31J..03L
- Keywords:
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- 1630 Impacts of global change;
- GLOBAL CHANGEDE: 1655 Water cycles;
- GLOBAL CHANGEDE: 1847 Modeling;
- HYDROLOGYDE: 1880 Water management;
- HYDROLOGY