Dynamic Changes in Plant Resource Use Efficiencies and Their Primary Influence Mechanisms in a Typical Desert Shrub Community

• Published in: Forests Vol. 12; no. 10; p. 1372
• Main Authors: Jiang, Yan, Tian, Yun, Zha, Tianshan, Jia, Xin, Bourque, Charles P.-A., Liu, Peng, Jin, Chuan, Jiang, Xiaoyan, Li, Xinhao, Wei, Ningning, Gao, Shengjie
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.10.2021
• Subjects: Abiotic factors; Acclimation; Acclimatization; Adaptation; Aridity; Artemisia ordosica; Climate change; Coefficient of variation; Desert plants; Divergence; Drought; dryland; Ecosystems; Environmental conditions; Leaf area; Leaves; Leymus secalinus; light use efficiency; Moisture content; Nitrogen; Photosynthesis; Plant species; Precipitation; Rain; resource use efficiency; Seasonal variations; Shrubs; Soil water; Species; Stomata; Stomatal conductance; Vapor pressure; Water content; Water shortages; Water supply; water use efficiency; Water vapor; Beijing China; United States > US; China
• ISSN: 1999-4907; 1999-4907
• DOI: 10.3390/f12101372

Understanding plant resource use efficiencies (RUEs) and their tradeoffs in a desert shrub community, particularly as it concerns the usage of water, light, and nitrogen, remains an ecological imperative. Plant RUEs have been widely used as indicators to understand plant acclimation processes to unfavorable environmental conditions. This study aimed to examine seasonal dynamics in RUEs in two widely distributed plant species in a typical desert shrub community (i.e., Artemisia ordosica and Leymus secalinus) based on in-situ measurements of leaf photosynthesis, specific leaf area (SLA), leaf nitrogen concentration (i.e., Nmass + Narea), and several site-related abiotic factors. Both species exhibited significant seasonal variation in RUEs, with a coefficient of variation (CV) >30% and seasonal divergence among the various RUEs. Seasonal divergence was largely controlled by variation in stomatal conductance (Gs), which was in turn influenced by variation in soil water content (SWC) and water vapor pressure deficit (VPD). RUEs between species converged, being positively correlated, yielding: (i) r2 = 0.40 and p < 0.01 for WUE; (ii) r2 = 0.18 and p < 0.01 for LUE; and (iii) r2 = 0.25 and p < 0.01 for NUE. RUEs for A. ordosica were mostly larger than those for L. secalinus, but less reactive to drought. This suggests A. ordosica was more conservative in its usage of available resources and was, therefore, better able to adapt to arid conditions. Resource use strategies between species differed in response to drought. Desert shrubs are projected to eventually replace grasses, as drought severity and duration increase with sustained regional climate change.