Desertification is a significant ecological and environmental problem worldwide. China is one of the countries affected seriously by long-term and large-scale land desertification particularly in water-limited regions in the northern part of the country.
Establishing fast-growing shrub plantings on active sand dunes is one of the main and effective measures for rapid sand dune fixation. Different sand fixing shrub species have different growth performance and dominant positions at different stages of dune fixation (Fig. 1). However, the detailed information underlying physiological differences is scarce.
Researchers at the Institute of Applied Ecology Chinese Academy of Sciences worked at Horqin Sandy Land with collaborators from the National Council of Science and Technology of Argentina on investigating the physiological characteristics in terms of xylem hydraulics and water use strategies of two important sand-fixing shrub species, i.e. Hedysarum fruitcosum and Caragana microphylla, in order to reveal the mechanism of their contrasting performances in sand dune re-vegetation projects.
The results showed that the two shrub species commonly used in combination for sand dune fixation in Horqin Sandy Land have contrasting ecophysiology with respect of water transport and use. H. fruticosum shows an ‘acquisitive’ water use strategy with greater hydraulic efficiency and carbon assimilation capability that would support potentially fast growth when water availability is relatively high, which would make it quickly gain dominance at the early stage of dune fixation. In contrast, C. microphylla shows a more ‘conservative’ water use strategy with enhanced resistance to drought-induced embolism and greater drought tolerance, which enabled it taking over the dominant position at the later stage of dune stabilization.
The results provide an important underlying mechanistic explanation for the clear switching of dominant positions between the two shrub species during the dune revegetation process.
The paper entitled “Switching of dominant positions between two sand-fixing shrub species during the dune revegetation process is underlain by their contrasting xylem hydraulics and water use strategies” has recently been published in Land Degradation & Development based on this collaborative work.
The study is financially supported by the National Natural Science Foundation of China, the CAS President’s International Fellowship Initiative (PIFI) and the Liaoning Revitalization Talents Program.
Fig.1 A schematic diagram showing the switching of dominant positions between Hedysarum fruitcosum and Caragana microphylla during the sand dune revegetation process.
Email: yueqian@iae.ac.cn
Publication Name: Guo Jingjing et al.
