Complementary water-use strategies mitigate drought impacts of mixed arbor-shrub stands in a loess gully area: a quantitative analysis
摘要
The loess gully area is a key zone for large-scale revegetation programs in China; however, accurate prediction of mixed arbor-shrub stands responses to variable drought intensities remains poorly quantified. Therefore, quantitative understanding water use strategies of typical revegetation stands under drought is crucial.
MethodsHere, we quantitatively investigated the seasonal water use strategies of mixed Caragana korshinskii Kom. and Armeniaca vulgaris Lam. in loess gully region during the growing season (April to October) in 2023, based on continuous monitoring of transpiration and 20 times sampling of δ2H and δ18O.
ResultsThe transpiration of A. vulgaris declined significantly in response to a summer drought by 19.7%, whereas that of C. korshinskii remained stable, indicating different drought resistance and resilience of these two species. Corresponding to different changes in transpiration, the two species also exhibited divergent water use strategies. In the wet spring, the two species both took up water predominantly from the surface layer (0–20 cm) (approximately 36.48% for C. korshinskii and 38.43% for A. vulgaris). However, under the summer drought, C. korshinskii switched to soil water of the deep layer (60–110 cm, by 37.39%), whereas A. vulgaris mainly relied on soil water of the middle layer (20–60 cm, by 37.73%).
ConclusionThe ability to switch to different water sources indicated that the mixed arbor – shrub stands could reduce interspecific stress and improved drought resistance and resilience. This study enhances our understanding of species-specific water-use strategies in mixed arbor – shrub stands under summer drought, and provides hydrological insights for water resource management in water-limited areas.