The distribution pattern of desert riparian forests and its relationship with soil moisture and soil properties in the low reaches of Heihe River Basin, China

Other literature type English OPEN
Ding, Jingyi ; Zhao, Wenwu ; Daryanto, Stefani ; Wang, Lixin ; Fan, Hao ; Feng, Qiang (2016)

Desert riparian forests are critical habitats that provide a variety of ecosystem services in arid environments. They are also endangered ecosystem types that are sensitive to disturbance and threatened by desertification. Despite of previous studies stressed on the interactions between desert riparian forests and water availability, the lack of comprehensive information on the forests distribution range and their relationship with soil properties constraints further conservation efforts of this community under a changing climate. In this study, vegetation community characteristics, soil moisture and soil properties were investigated within a 3000 m radius around the river channel in the low reaches of Heihe River Basin, northwest China to determine the distribution pattern of desert riparian forests and their relationship with environmental factors. We found that desert riparian forests mainly distributed within the range of 2500 m from the river channel and the first 1000 m was regarded as the optimum range. Five types of vegetation communities were identified based on Two-way Indicator Species Analysis (TWINSPAN) and they gradually shifted from the riparian tree-shrub-herb communities to riparian-desert shrubs with increasing distance from the river channel. Vegetation community coverage and diversity indices formed bimodal patterns while community height and density declined significantly as the distance from the river increased. Soil moisture, soil physical properties, and soil nutrition explained 53.6 % of the variance in community characteristics and different environment variables influenced different community characteristics. Soil moisture, accounting for 62.7 % of the total explanation, mainly influenced the community coverage and density. Soil physical properties (e.g., bulk density, soil particle composition) exerted influence on shrub layer, while soil nutrition mainly affected community richness. With surface (0–30 cm) and deep (100–200 cm) soil moisture, bulk density and total phosphorus regarded as major determining factors in the community structure and diversity, conservation measures that protect the soil structure and prevent soil moisture deficiency (e.g., artificial soil cover and water conveyance channel) were suggested to better protect the desert riparian forests under climate change and intensive human disturbance.
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