How changes of groundwater level affect the desert riparian forest ecosystem in the Ejina Oasis,Northwest China

摘要

Groundwater is a key factor controlling the growth of vegetation in desert riparian systems.It is important to recognise how groundwater changes affect the riparian forest ecosystem.This information will not only help us to understand the ecological and hydrological process of the riparian forest but also provide support for ecological recovery of riparian forests and water-resources management of arid inland river basins.This study aims to estimate the suitability of the Water Vegetation Energy and Solute Modelling(WAVES)model to simulate the Ejina Desert riparian forest ecosystem changes,China,to assess effects of groundwater-depth change on the canopy leaf area index(LAI)and water budgets,and to ascertain the suitable groundwater depth for preserving the stability and structure of desert riparian forest.Results demonstrated that the WAVES model can simulate changes to ecological and hydrological processes.The annual mean water consumption of a Tamarix chinensis riparian forest was less than that of a Populus euphratica riparian forest,and the canopy LAI of the desert riparian forest should increase as groundwater depth decreases.Groundwater changes could significantly influence water budgets for T.chinensis and P.euphratica riparian forests and show the positive and negative effects on vegetation growth and water budgets of riparian forests.Maintaining the annual mean groundwater depth at around 1.7-2.7 m is critical for healthy riparian forest growth.This study highlights the importance of considering groundwater-change impacts on desert riparian vegetation and water-balance applications in ecological restoration and efficient water-resource management in the Heihe River Basin.