The change of hydrological variables and its effects on vegetation in Central Asia

Qing Peng,Wenhui Guo,Cheng Li,Yelin Jiang,Ranghui Wang

doi:10.1007/s00704-021-03730-w

Abstract

Water is an important factor that affects local ecological environments, especially in drylands. The hydrological cycle and vegetation dynamics in Central Asia (CA) have been severely affected by climate change. In this study, we employed data from Gravity Recovery and Climate Experiment (GRACE), Global Land Data Assimilation System (GLDAS), Global Land Evaporation Amsterdam Model, and Climate Research Unit to analyze the spatiotemporal changes in hydrological factors (terrestrial water storage (TWS), evapotranspiration, precipitation, and groundwater) in CA from 2003 to 2015. Additionally, the spatiotemporal changes in vegetation dynamics and the influence of hydrological variables on vegetation were analyzed. The results showed that the declining rates of precipitation, evapotranspiration, GRACE-TWS change, GLDAS-TWS change and GW change were 0.40 mm/year, 0.11 mm/year, 50.46 mm/year (p < 0.05), 8.38 mm/year, and 41.18 mm/year (p < 0.05), respectively. Human activity (e.g., groundwater pumping) was the dominant in determining the GW decline in CA. Precipitation dominated the changes in evapotranspiration, GRACE-TWS and GLDAS-TWS (p < 0.05). The 2- to 3-month lagging signal has to do with the transportation from the ground surface to groundwater. The change in the normalized difference vegetation index (NDVI) from 2003 to 2015 indicated the slight vegetation degradation in CA. The results highlighted that precipitation, terrestrial water storage, and soil moisture make important contributions to the vegetation dynamics changes in CA. The effect of precipitation on vegetation growth in spring was significant (p < 0.05), while the soil moisture effect on vegetation in summer and autumn was higher than that of precipitation.

Highlights

The results showed that the declining rates of precipitation, evapotranspiration, Gravity Recovery and Climate Experiment (GRACE)-Terrestrial water storage (TWS) change, Global Land Data Assimilation System (GLDAS)-TWS change and GW change were 0.40 mm/year, 0.11 mm/year, 50.46 mm/year (p < 0.05), 8.38 mm/year, and 41.18 mm/year (p < 0.05), respectively
In areas threatened by water storage, hydrological cycle is the dominating factor for sustaining terrestrial ecosystems, as its direct impact on vegetation dynamics (Lohse et al 2009; Reyer et al 2013; Ndehedehe et al 2019)
Since rivers in Central Asia (CA) are mainly inland rivers (Deng and Chen 2017), we focus on the relationship between P minus ET (P-ET) and TWSC

Summary

Introduction

In areas threatened by water storage, hydrological cycle is the dominating factor for sustaining terrestrial ecosystems, as its direct impact on vegetation dynamics (Lohse et al 2009; Reyer et al 2013; Ndehedehe et al 2019). The hydrologic cycle in CA has been intensified and accelerated, which has led to changes in the local water balance (Bernauer and Siegfried 2012; Deng and Chen 2017). These modifications of the water balance result in changes to terrestrial ecosystems, which cause a decrease in biodiversity and increases in salinization and desertification (D’Odorico et al 2013; Feng et al 2016)

Results

Discussion

Conclusion