The natural Populus euphratica forest in the Tarim River Basin of Xinjiang occupies 89% and 54% of the total P. euphratica forests in China and in the world, respectively. Desert riparian P. euphratica forest plays an important role in the ecological balance of the Tarim River Basin, and protects the development of oases in this basin.
However, since the 1950s, the over exploitation of water resources in the Tarim River has led to the loss of P. euphratica forest in the lower reaches of this river. Regenerating and protecting the degraded desert riparian ecosystem of the Tarim River Basin are significant for maintaining the stable and healthy development of the ecological system of the desert oasis.
Using the basic theory and method of eco-hydrology and dendrohydrology, a research team led by XU Hailiang from Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences put forward an optimized flooding disturbance model for the survival of the seedlings of P. euphratica by a large number of vegetation flooding experiments and samplings of P. euphratica tree rings. At the same time, they developed a quantitative model of relationship between different groundwater depths and tree-ring width indices, and determined the minimum groundwater depth of P. euphraticas with different diameter at breast heights.
During the period of seed germination to seedling growth, the P. euphratica forest should be flooded 2–3 times per year with an intensity of 25–30 m3/s. Moreover, the most suitable flood duration is 15–20 days. They also pointed that the actual groundwater depth should be smaller than the minimum groundwater depth for each tree growth stage (i.e. 4.0, 5.0–5.4, 6.9 and 7.8 m for P. euphratica young trees, near-mature trees, mature trees and over-mature trees, respectively) in order to protect the desert riparian forest. The most suitable requirements of ecological water conveyance amount for maintaining P. euphratica growth and minimum groundwater depths in the lower reaches of the Tarim River is 311×106–320×106 m3.
The study can provide technical information to sustain the ecological development of the Tarim River Basin, and also to offer scientific guidance that can be used in similar areas to regenerate and protect P. euphratica forest around the world.
This study was published online first in Scientific Reports on 20 October 2015.
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