Articles | Volume 21, issue 5
https://doi.org/10.5194/hess-21-2405-2017
https://doi.org/10.5194/hess-21-2405-2017
Research article
 | 
09 May 2017
Research article |  | 09 May 2017

The spatial distribution and temporal variation of desert riparian forests and their influencing factors in the downstream Heihe River basin, China

Jingyi Ding, Wenwu Zhao, Stefani Daryanto, Lixin Wang, Hao Fan, Qiang Feng, and Yaping Wang

Abstract. Desert riparian forests are the main restored vegetation community in Heihe River basin. They provide critical habitats and a variety of ecosystem services in this arid environment. Since desert riparian forests are also sensitive to disturbance, examining the spatial distribution and temporal variation of these forests and their influencing factors is important to determine the limiting factors of vegetation recovery after long-term restoration. In this study, field experiment and remote sensing data were used to determine the spatial distribution and temporal variation of desert riparian forests and their relationship with the environmental factors. We classified five types of vegetation communities at different distances from the river channel. Community coverage and diversity formed a bimodal pattern, peaking at the distances of 1000 and 3000 m from the river channel. In general, the temporal normalized difference vegetation index (NDVI) trend from 2000 to 2014 was positive at different distances from the river channel, except for the region closest to the river bank (i.e. within 500 m from the river channel), which had been undergoing degradation since 2011. The spatial distribution of desert riparian forests was mainly influenced by the spatial heterogeneity of soil properties (e.g. soil moisture, bulk density and soil particle composition). Meanwhile, while the temporal variation of vegetation was affected by both the spatial heterogeneity of soil properties (e.g. soil moisture and soil particle composition) and to a lesser extent, the temporal variation of water availability (e.g. annual average and variability of groundwater, soil moisture and runoff). Since surface (0–30 cm) and deep (100–200 cm) soil moisture, bulk density and the annual average of soil moisture at 100 cm obtained from the remote sensing data were regarded as major determining factors of community distribution and temporal variation, conservation measures that protect the soil structure and prevent soil moisture depletion (e.g. artificial soil cover and water conveyance channels) were suggested to better protect desert riparian forests under climate change and intensive human disturbance.

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Short summary
In this study, we focused on exploring the spatial distribution and temporal variation of desert riparian forests and their influencing factors based on field experiment and remote sensing data. Our result revealed how the environmental factors shape the spatial distribution and temporal variation of desert riparian forest in the downstream Heihe river. The results of this study provide support for the effective restoration of desert riparian forest in the hyperarid zone.