Different Water Use Strategies of Juvenile and Adult Caragana intermedia Plantations in the Gonghe Basin, Tibet Plateau

Abstract

BackgroundIn a semi-arid ecosystem, water is one of the most important factors that affect vegetation dynamics, such as shrub plantation. A water use strategy, including the main water source that a plant species utilizes and water use efficiency (WUE), plays an important role in plant survival and growth. The water use strategy of a shrub is one of the key factors in the evaluation of stability and sustainability of a plantation.Methodology/Principal Findings Caragana intermedia is a dominant shrub of sand-binding plantations on sand dunes in the Gonghe Basin in northeastern Tibet Plateau. Understanding the water use strategy of a shrub plantation can be used to evaluate its sustainability and long-term stability. We hypothesized that C. intermedia uses mainly deep soil water and its WUE increases with plantation age. Stable isotopes of hydrogen and oxygen were used to determine the main water source and leaf carbon isotope discrimination was used to estimate long-term WUE. The root system was investigated to determine the depth of the main distribution. The results showed that a 5-year-old C. intermedia plantation used soil water mainly at a depth of 0–30 cm, which was coincident with the distribution of its fine roots. However, 9- or 25-year-old C. intermedia plantations used mainly 0–50 cm soil depth water and the fine root system was distributed primarily at soil depths of 0–50 cm and 0–60 cm, respectively. These sources of soil water are recharged directly by rainfall. Moreover, the long-term WUE of adult plantations was greater than that of juvenile plantations.ConclusionsThe C. intermedia plantation can change its water use strategy over time as an adaptation to a semi-arid environment, including increasing the depth of soil water used for root growth, and increasing long-term WUE.

Spatial Patterns and Natural Recruitment of Native Shrubs in a Semi-arid Sandy Land

“…In semi-arid sandy land, soil moisture and sand drift are the predominant factors that influence plant survival [4], [23], [42]. Given the low precipitation, soil moisture in the Mu Us is usually low, thereby limiting the carrying capacity of the land for shrubs, i.e.…”

Effects of different vegetation restoration on soil water storage and water balance in the Chinese Loess Plateau

“…Hence, a proper understanding of how water balance limits and controls afforestation is particularly important. Water balance is not only important in investigating the ecosystem function and catchment hydrology (Issa et al, 2011), but is also necessary for developing viable water-saving management strategies that support high water-use efficiency and economic benefits in regions subjected to water scarcity (Jia et al, 2012). To encourage proper reforestation practices, common species need to be investigated to elucidate their water balance and determine their suitability for developing stable ecosystems that can improve the provision of ecosystem services and reverse degradation processes (Derak and Cortina, 2014).…”

Age‐related water uptake patterns of alpine plantation shrubs in reforestation region of Qinghai–Tibetan Plateau based on stable isotopes

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“…Water is crucial to terrestrial plants, affecting their survival and growth, particularly in arid and semiarid regions (Eggemeyer et al, 2009;Zhu & Jia, 2011;Zhou, Zhao, & Zhang, 2017). Therefore, plants have evolved various water-use strategies to cope with water stress, such as increasing the utilization of stable water sources (e.g., groundwater) or reducing water loss (e.g., stomatal limitation) during their different life-history stages (Donovan & Ehleringer, 1992;Jia, Zhu, & Liu, 2012;Su, Li, Liu, Xu, & Sun, 2014;Wu et al, 2018). Mature plants generally have deeper roots and rely on deeper water sources than do young plants, thereby alleviating the influence of drought during the growing season.…”

“…Mature plants generally have deeper roots and rely on deeper water sources than do young plants, thereby alleviating the influence of drought during the growing season. Thus, young plants are more susceptible to water shortages and stress compared with mature adult plants (Donovan & Ehleringer, 1992;Jia et al, 2012;Kerhoulas, Kolb, & Koch, 2013).…”