Open access peer-reviewed chapter

Water Use Strategy of Four Desert Shrubs in Gonghe Basin, Qinghai-Tibetan Plateau

Written By

Yajuan Zhu

Submitted: October 27th, 2015 Reviewed: March 18th, 2016 Published: August 24th, 2016

DOI: 10.5772/63195

From the Edited Volume

Water Stress in Plants

Edited by Ismail Md. Mofizur Rahman, Zinnat Ara Begum and Hiroshi Hasegawa

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Abstract

Gonghe basin is located in the ecotone from the semi-arid to arid zone on the northeastern Qinghai-Tibetan Plateau. Caragana intermedia and Caragana korshinskii are dominant on sand dunes. Salix psammophila and Salix cheilophila are mainly distributed on interdune. Water source of four desert shrubs was examined by δD and δ18O, and their long-term water use efficiency (WUE) was compared by leaf δ13C. Four desert shrubs used different depths of soil water depending on their availability in different seasons, including shallow soil water recharged by rain in spring or summer and deep soil water recharged by ground water. The reliability on ground water of two Salix shrubs on interdune was more significant than two Caragana shrubs on sand dunes. Moreover, the WUE of four shrubs decreased in drought spring. Two shrubs in Caragana had similar WUE in the growing season. However, the WUE of S. psammophila was always higher than that of S. cheilophila, which might have more adaptability in Gonghe Basin.

Keywords

  • water source
  • water use efficiency (WUE)
  • stable isotope
  • soil water
  • ground water

1. Introduction

In desert ecosystems, water is a restrictive factor for plant survival and growth because of low and unpredictable precipitation and high evaporation [1, 2]. The ability to use rainwater in spring and summer is important for plant phenology and growth [3]. Additionally, the sustainable water source is necessary for plant growth especially in the drought period, such as deep soil water or ground water [4]. A stable isotope technology is often used to study the water use strategy of desert plants. Generally, there is no stable isotope fractionation during water uptake by root system or water transportation in the xylem of most plant species. Thus, the main water source can be distinguished by comparing the δD or δ18O value of xylem water with that of the potential water source, for example, rain, snow, river, lake, soil water or ground water [1]. Further, leaf δ13C value of C3 plants is positively related to their long-term water-use efficiency (WUE). The δ13C value decreased from spring to autumn in the growing season and increased in the drought period [4].

Previous studies with the stable isotope of hydrogen or oxygen indicated that woody plant species used different water sources in desert or other arid and semi-arid ecosystems. Firstly, many trees and shrubs mainly used shallow soil water recharged by rain, for example, Artemisia ordosicain Mu Us Sandy Land [5], Pinus edulisand Juniperus osteospermain Utah [6], Larix sibiricaand Potentilla fruticosain the mountain forest along the Kherlen River of Mongolia [7], Senecio filaginoidesand Mulinum spinosumin Patagonian steppe [8], Nitraria tangutorumand Artemisia arenariain Badain Jaran Desert [9], Sarcobatus vermiculatusin San Luis Valley of Colorado [10] and Haloxylon persicumin Gurbantunggut Desert [11]. Secondly, some deep-rooted shrubs and trees mainly used ground water, for example, Sabina vulgarisand Salix matsudanain Mu Us Sandy Land [12], Populus fremontiiin the non-saline habitat of Colorado River Basin [13], Ericameria nauseosain San Luis Valley [10], Ulmus pumilain Hunshandake Sandy Land [14], Pinus sylvestrisvar. mongolicain Horqin Sandy Land [15], Populus euphraticaalong Heihe River [16] and Haloxylon ammodendronin Gurbantunggut Desert [11]. Thirdly, few shrubs or trees with dimorphic root systems used both soil water recharged by rain and deep soil water recharged by ground water and even ground water. S. vermiculatusused ground water during dry periods but used deep soil water large amounts of rainfall in San Luis Valley [10].

Gonghe Basin is located in the northeastern Qinghai-Tibetan Plateau, which is the ecotone from semi-arid to arid region, with the altitude varying from 2600 to 3400 m. It contains part of Gonghe County, Guinan County and Xinghai County of Qinghai Province. The dominant vegetation is steppe and desert steppe. The basin is as long as 210 km in East and West, and as wide as 60 km in South and North, with a total area of 13,800 km2. It is one of the most vulnerable land desertification area in Qinghai Province. The area of desertified land is 3530 km2, which accounts for 25.58% of the total area. The ecological security in the upper reaches of Yellow River has been affected significantly by land desertification in Gonghe Basin, especially Longyangxia Reservoir [17]. In order to control and prevent land desertification, large areas were planted with trees and shrubs to form the shelterbelt system in the ecotone between oasis and desert to protect farms, villages and roads in Gonghe Basin. Some trees in Populuswere planted by transplanting inside oasis. Some shrubs in Caraganawere planted by seeding on sand dunes. Other shrubs in Salixwere planted by cutting on interdune.

In this chapter, the main water source of four dominant desert shrubs is compared by stable hydrogen and oxygen isotopes in the growing season (May, July and September). The water use ratio of different sources was analysed by Iso-source 1.3.1 software [18]. Two shrubs in Caraganaon sand dunes may use shallow soil water recharged by rain and deep soil water recharged by ground water. Two shrubs in Salixon interdune may use shallow soil water recharged by rain, deep soil water recharged by ground water and even ground water. Further, the long-term WUE is compared using their leaf stable carbon isotope. The WUE of four shrubs may be higher in drought spring than in summer and autumn.

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2. Water source and long-term WUE of four desert shrubs

2.1. Four dominant desert shrubs in Gonghe Basin

This study was conducted at Gonghe Desert Ecosystem Research Station, which is located in the mid-west Gonghe Basin and belongs to Shazhuyu Town, Gonghe County (36°16'N, 100°16'E, altitude 2874 m). The mean annual air temperature is only 2.4 °C, and the mean annual forest free day is only 91 days. The mean annual precipitation is 246.3 mm, which is concentrated from July to September. Two shrubs in Caraganaand Salix psammophilawere introduced from Ordos City, Inner Mongolia Autonomous Region. Salix cheilophilawas introduced from Guinan County, which is located in the eastern Gonghe Basin.

Caragana intermedia(pea shrub) is a shrub with a height of 0.7−1.5 m growing on fixed sand dunes or flat sandy land. It is used as a good sand-fixing and afforest plant [19]. The mean height of C. intermediawas 1.04 m at Gonghe Station. The root system of C. intermediawas as deep as 1.3 m at Gonghe Station [20]. Caragana korshinskii(white pea shrub) is a shrub or small tree with a height of 1−4 m growing on fixed sand dunes. It is a good sand-fixing and soil conservation plant [21]. The mean height of C. korshinskiiwas 1.82 m at Gonghe Station.

S. psammophila(sandy willow) is a shrub with a height of 2−4 m, which inhabits on moving or semi-fixed sand dunes and interdune. S. psammophilais fast growing, tolerant to drought and sand burial and a good sand-fixing plant [21].The mean height of S. psammophilawas 2.82 m at Gonghe Station. The fine root of S. psammophilawas 1.5 m deep in its original distribution area (Mu Us Sandy Land) [22]. S. cheilophila(black willow) is a small tree or big shrub, which is as tall as 5.4 m and inhabits slope, valley and riverbank. S. cheilophilais a mesophyte and hygrophyte and is often used as a sand-fixing or riparian plant [23]. The mean height of S. cheilophilawas 3.72 m at Gonghe Station. The root system of S. cheilophilawas 2.0 m deep at Gonghe Station [24].

2.2. Precipitation in the growing season and soil moisture in four desert shrubs plantation

The total precipitation at the study site was 137.5 mm from May 1 to September 13, 2014. The monthly precipitation was 8.8, 61.6, 37.8 and 28.7 mm in May, June, July and August, respectively (Figure 1). The maximal daily precipitation (18.9 mm) occurred on June 12. Before field sampling in July, 6.4 mm rain occurred on July 8, and in September, the precipitation was only 0.4 mm.

Figure 1.

Precipitation at Gonghe Station from May to August, 2014.

Soil water content in C. intermediaplantation was significantly different in different depths on May 27 and July 20 but was similar on September 11 (Figure 2). On May 27, the water content in shallow soil (10 and 25 cm) was significantly higher than that in deeper soil (75−150 cm). On July 20, the water content in surface soil (10 cm) and subsurface soil (25 cm) was significantly higher than that in deeper soil (50−150 cm).

Soil water content in C. korshinskiiplantation was similar in different depths on May 27 but was significantly different in different depths on July 23 and September 11 (Figure 2). On July 23, the water content in surface soil (10 cm) was significantly higher than in deeper depths (25−150 cm), and the water content in 150 cm was significantly higher than in medium depths (25−100 cm). On September 11, the water content in 150 cm was significantly higher than in shallower soil (10−100 cm).

Soil water content in S. psammophilaplantation was significantly different in different depths on May 26, July 17 and September 11 (Figure 2). On May 26, the water content in middle and deep soil (50−150 cm) was significantly higher than that in shallow soil (10 and 25 cm). On July 17, the water content in middle and deep soil (50−150 cm) was significantly higher than that in shallow soil (25 cm). On September 11, the water content in middle soil (50 cm) and deep soil (150 cm) was significantly higher than that in shallow soil (10 and 25 cm).

Soil water content in S. cheilophilaplantation was significantly different in different depths on May 26 and September 11 but was similar in different depths on July 17 (Figure 2). On May 26, the water content in middle and deep soil (50−200 cm) was significantly higher than that in surface soil (10 cm). On September 11, the water content in deep soil (100−200 cm) was significantly higher than in surface soil (10 cm) and middle soil (50 cm).

Figure 2.

Soil water content in different depths in four desert shrub plantations.

2.3. Water source of four desert shrubs in different seasons

The δ18O ratio of xylem water of C. intermedia, C. korshinskii, S. psammophilaand S. cheilophilawas located in the right side of global meteoric water line (Figure 3), which indicated that the water source of four shrubs was affected by isotope enrichment induced by evaporation. The δD and δ18O value of some soil water were closer to ground water, which indicated deep soil water was recharged by ground water. The δD and δ18O value of some soil water were closer to some rainwater, which indicated that shallow soil water is recharged by rain. The δD and δ18O value of xylem water of two Salixshrubs were closer to ground water, which indicated that they might use ground water.

Figure 3.

The value of δD and δ18O in xylem and soil water of four desert shrubs, ground water, rainwater and global meteoric water line (GMWL) [4].

2.3.1. Water source of two Caraganashrubs on sand dunes

On May 27, the value of δD and δ18O in xylem water of C. intermediawas closer to soil water in 50 cm (Figure 4). On July 20, the value of δD and δ18O in xylem water of C. intermediawas closer to soil water in 10−50 cm, and the value of δD and δ18O of soil water in 10 cm was closer to rain water on July 8 (6.4 mm). On September 11, the value of δD and δ18O in xylem water of C. intermediawas closer to soil water in 100−150 cm and ground water.

Figure 4.

The value of δD and δ18O in xylem water ofCaragana intermedia, soil water and ground water. Full line is ground water. Dot line is 6.4 mm rainwater on July 8.

On May 27, the ratio of δD and δ18O in xylem water of C. korshinskiiwas closer to soil water in 50−100 cm and ground water (Figure 5). On July 23, the value of δD and δ18O in xylem water of C. korshinskiiwas closer to soil water in 50−75 cm, which was closer to rain water on July 21 (8.0 mm). On September 11, the value of δD and δ18O in xylem water of C. korshinskiiwas closer to soil water in 25−75 cm.

Figure 5.

The value of δD and δ18O in xylem water ofCaragana korshinskii, soil water and ground water. Full line is ground water. R is rainwater.

Iso-Source analysis showed that C. intermediamainly used 10−100 cm soil water on May 27, which accounted for 82.0% of its total water source. On July 20, C. intermediamainly used 10 cm soil water, which accounted for 65.7% of its total water source. On September 11, C. intermediamainly used 50−150 cm soil water and ground water, which accounted for 86.5% of its total water source (Table 1).

Water sourceMay 27July 20September 11
Soil water 10 cm22.8 ± 12.265.7 ± 4.56.1 ± 5.3
25 cm22.0 ± 15.38.8 ± 7.97.4 ± 6.5
50 cm15.9 ± 13.87.6 ± 6.910.5 ± 9.1
75 cm10.9 ± 9.35.8 ± 5.311.6 ± 1.0
100 cm10.4 ± 8.94.5 ± 4.216.7 ± 14.5
150 cm8.9 ± 7.53.7 ± 3.622.2 ± 16.8
Ground water9.1 ± 7.83.8 ± 3.625.5 ± 12.9

Table 1.

Water use ratio of Caragana intermediato different sources (%, mean ± SD).

Iso-Source analysis showed that C. korshinskiievenly used 10−150 cm soil water and ground water on May 27. On July 23, C. korshinskiimainly used 25−150 cm soil water, which accounted for 82.8% of its total water source. On September 11, C. korshinskiimainly used 10−150 cm soil water, which accounted for 94.6% of its total water source (Table 2).

Water sourceMay 27July 23September 11
Soil water 10 cm16.8 ± 9.39.7 ± 7.318.2 ± 10.6
25 cm18.3 ± 12.212.0 ± 8.120.9 ± 14.5
50 cm15.5 ± 13.417.9 ± 13.920.0 ± 16.6
75 cm13.1 ± 11.113.9 ± 10.811.1 ± 8.2
100 cm12.3 ± 10.410.4 ± 7.612.8 ± 9.2
150 cm11.2 ± 9.428.6 ± 6.111.6 ± 7.8
Ground water12.9 ± 11.07.5 ± 5.85.4 ± 3.7

Table 2.

Water use ratio of Caragana korshinskiito different sources (%, mean ± SD).

On sand dunes of Gonghe Basin, C. intermediaused 10−100 cm soil water in spring, 10 cm shallow soil water recharged by rain in summer and 50−150 cm medium and deep soil water and ground water in autumn (Figure 4, Table 1). However, C. korshinskiiused 10−150 cm soil water and ground water in spring, 25−150 cm soil water in summer and 10−150 cm soil water in autumn (Figure 5, Table 2). Therefore, two Caraganashrubs used shallow soil water recharged by rain and deep soil water recharged by ground water in spring or autumn, and even used few ground water when soil water is not enough for their water requirements (Figure 2). In summer, surface soil water recharged by rain was enough for C. intermedia(Figures 1 and 4), whereas C. korshinskiistill needed both of shallow water recharged by rain and deep soil water recharged by ground water (Figures 1 and 5).

The resource-dependent water use strategy of two Caraganashrubs on sand dunes is an ecological adaptation to the semi-arid climate in Gonghe Basin, which is similar to other shrubs in arid and semi-arid regions. A. ordosicamainly used soil water within 50 cm in Mu Us Sandy Land [12]. In San Luis valley of Colorado, Chrysothamnus greeneionly occurs in sites with water table deeper than 2 m and only use soil water recharged by rain [25]. Caragana microphyllamainly used 100 cm deep soil water recharged by snow in Xilin River Basin of Inner Mongolia [26]. Both of N. tangutorumand A. arenariaused 30−90 cm middle soil water in May, within 30 cm shallow soil water in July and below 120 cm deep soil water in September on sand dunes of Badain Jaran Desert [9]. Ceratoides lateensused 10−50 cm soil water in Qaidam Basin [27]. In Gurbantunggut Desert, H. persicumused 40−100 cm middle soil water on sand dunes when upper soil was abundant in early spring; however, it used 100−300 cm deep soil water when upper soil was depleted in summer [11].

The temporal difference in the main water source for a typical desert shrub is associated with precipitation change in different years. In this study, the ground water table is less than 3 m on interdune. C. intermediaalso used ground water in September when precipitation was only 137.5 mm in the total growing season. However, C. intermediamainly used soil water within 50 cm recharged by rain in middle August of 2009 with 155.5 mm precipitation since May [20]. On the other side, the spatial difference in the main water source for a typical desert shrub is associated with ground water table in different sites. C. korshinskiiused 0−30 cm and 60−90 cm soil water in Ulanbuh Desert with ground water table deeper than 6 m [28]. At sites with water table less than 2 m in San Luis Valley, S. vermiculatusand Chrysothamnus nauseosusused top 50 cm soil water recharged by rain in a wet year. At sites with water table deeper than 2 m, they used ground water in the pre-monsoon season, whereas they used 30−40 cm upper soil water recharged by rain in the monsoon season [25].

2.3.2. Water source of two Salixshrubs on interdune

On May 26 and July 17, the value of δD and δ18O in xylem water of S. psammophilawas closer to ground water and soil water at depths of 25 and 50 cm (Figure 6). On July 17, the value of δD and δ18O of soil water at a depth of 10 cm was closer to rainwater on July 8 (6.4 mm). On September 11, the value of δD and δ18O in xylem water of S. psammophilawas closer to that of ground water and soil water at depths of 50−150 cm.

Figure 6.

The value of δD and δ18O in xylem water ofSalix psammophila, soil water and ground water. Full line is ground water. Dot line is 6.4 mm rainwater on July 8.

On May 26, the value of δD and δ18O in xylem water of S. cheilophilawas closer to ground water and soil water in 25 and 50 cm (Figure 7). On July 17, the value of δD and δ18O in xylem water of S. cheilophilawas closer to ground water; and the value of δD and δ18O of soil water in 10 cm was closer to rainwater on July 8 (6.4 mm). On September 11, the value of δD and δ18O in xylem water of S. cheilophilawas closer to ground water and soil water in 50 and 100−200 cm.

Figure 7.

The value of δD and δ18O in xylem water ofSalix cheilophila, soil water and ground water. Full line is ground water. Dot line is 6.4 mm rainwater on July 8.

Iso-Source analysis showed that S. psammophilaevenly used 10−150 cm soil water and ground water on May 26. On July 17, S. psammophilamainly used 10 and 25 cm soil water and ground water, which accounted for 63.0% of its total water source. On September 11, S. psammophilamainly used 50−150 cm soil water and ground water, which accounted for 79.6% of its total water source (Table 3).

Iso-Source analysis showed that S. cheilophilamainly used 10 and 25 cm soil water and ground water on May 26, which accounted for 70.7% of its total water source. On July 17, S. cheilophilaevenly used 10−200 cm soil water and ground water. On September 11, S. cheilophilamainly used 100−200 cm soil water, which accounted for 81.8% of its total water source (Table 4).

Water sourceMay 26July 17September 11
Soil water 10 cm13.0 ± 8.026.2 ± 12.09.0 ± 6.3
25 cm16.0 ± 12.023.0 ± 16.911.3 ± 8.4
50 cm14.3 ± 11.99.9 ± 8.616.8 ± 14.6
75 cm12.8 ± 10.48.9 ± 7.716.1 ± 13.1
100 cm12.6 ± 10.28.9 ± 7.716.2 ± 13.2
150 cm14.3 ± 11.99.3 ± 8.014.4 ± 10.9
Ground water17.0 ± 14.113.8 ± 12.016.1 ± 13.7

Table 3.

Water use ratio of Salix psammophilato different sources (%, mean ± SD).

Water sourceMay 26July 17September 11
Soil water 10 cm16.7 ± 7.117.0 ± 8.82.2 ± 2.1
25 cm31.4 ± 20.218.8 ± 13.22.2 ± 2.1
50 cm9.2 ± 7.713.1 ± 11.27.6 ± 6.8
100 cm7.7 ± 6.411.5 ± 9.727.9 ± 19.9
150 cm6.2 ± 5.211.7 ± 9.928.0 ± 19.9
200 cm6.2 ± 5.212.3 ± 10.525.9 ± 19.9
Ground water22.6 ± 12.215.6 ± 13.65.5 ± 5.0

Table 4.

Water use ratio of Salix cheilophilato different sources (%, mean ± SD).

On interdune of Gonghe Basin, S. psammophilaused 10−150 cm soil water and ground water in spring, 10−25 cm shallow soil water and ground water in summer and 50−150 cm medium and deep soil water and ground water in autumn (Figure 6, Table 3). However, S. cheilophilaused 10−25 cm shallow soil water and ground water in spring, 10−200 cm soil water and ground water in summer and 100−200 cm deep soil water in autumn (Figure 7, Table 4). Therefore, two Salixshrubs used ground water or deep soil water recharged by ground water as long-term stable water source. Moreover, S. psammophilaand S. cheilophilaalso used shallow soil water recharged by rain in spring and summer, respectively (Figures 1, 6, and 7).

The resource-dependent water use strategy of two Salixshrubs in Gonghe Basin is similar to other trees or shrubs in arid and semi-arid regions. S. matsudanaand S. vulgarismainly used deep soil water and ground water in Mu Us Sandy Land [12]. In San Luis Valley of Colorado, S. vermiculatusand C. nauseosusused soil water recharged by rain in a wet year but deep soil water and ground water in a dry year [25]. E. nauseosadepended on ground water, whereas S. vermiculatusused ground water during dry periods but used deep soil water after large rainfall in San Luis valley [10]. J. osteospermaabsorbed shallow soil water in early spring and gradually depended on deep soil water with soil drought in Utah [6]. P. sylvestrisvar. mongolicaprimarily used 20−60 cm soil water both at the top of fixed sand dune and in interdune lowland in Horqin Sandy Land [29]. Moreover, it only used soil water during the higher precipitation year, whereas it used soil water and relied on ground water during the lower precipitation year [15]. U. pumilaalways used stable ground water in Hunshandake Sandy Land [14]. N. tangutorummainly used 50−100 cm soil water and ground water from June to September in Golmud of Qaidam Basin [30]. In Nuomuhong of Qaidam Basin, N. tangutorumand Tamarix ramosissimaused 50−70 cm soil water, whereas Ephedra sinicaand Calligonum mongolicumevenly used 0−90 cm soil water. Moreover, these four shrubs increased to use ground water in the late growing season [27]. Along the lower reaches of Heihe River, different aged P. euphraticaused different water sources. Young forests primarily relied on soil water from 0 to 50 cm (mean > 45%), while mature and over-mature forests used water from deeper than 100 cm which derived primarily from ground water [16]. When the upper soil water was abundant in early spring, H. ammodendronmainly used shallow soil water on sand dunes of Gurbantunggut Desert. When the upper soil water was depleted in summer, H. ammodendronmainly used ground water [11]. Therefore, ground water is an important water source for trees and shrubs in arid and semi-arid regions, especially in the drought period. Global climate change may result in the increase of extreme drought in the arid region [31]. Plant species using stable ground water or deep soil water may have more adaptability than those only using shallow soil water recharged by rain in the drought period.

2.4. Long-term WUE of four desert shrubs

Leaf carbon discrimination (Δ, ‰) was converted from its δ13C value using an atmospheric carbon dioxide ratio of −8‰ [32]. The leaf Δ value was significantly different (P< 0.001) in different months for C. intermedia, C. korshinskii, S. psammophilaandS. cheilophila, respectively (Figure 8). The leaf Δ value of C. intermedia, C. korshinskiiand S. psammophilaincreased significantly on May 26, and from July 17 to September 11. The leaf Δ value of S. cheilophilawas significantly lower on May 26 than that on July 17 or September 11. The leaf Δ value of C. intermediawas similar to C. korshinskiiin three months. The leaf Δ value of S. psammophilawas lower than S. cheilophilain three months.

Figure 8.

Leaf carbon discrimination of four desert shrubs. Different lower case letters indicate significant difference in different months, according to Duncan’s test (P< 0.05).

The long-term WUE is negatively related to the leaf Δ value of C3 plants. There were seasonal dynamics of WUE in two Caraganashrubs on sand dunes of Gonghe Basin, which were lower in spring and increased in summer and autumn (Figure 6). Soil water content at surface soil was lower in spring than in summer (Figure 2) because of low precipitation (Figure 1). It was suggested that both of two Caraganashrubs increased WUE to adapt to drought. Similarly, the WUE of N. tangutorumwas higher in summer than in autumn in Ulanbuh Desert [28]. The WUE of P. euphraticawas highest in May and decreased in the middle and late growing season in lower reaches of Heihe River, west Inner Mongolia [33].

There were seasonal dynamics of long-term WUE indicated by the leaf Δ value in two Salixshrubs on interdune of Gonghe Basin, which were higher in spring than in summer and autumn (Figure 7). Soil water content of two Salixplantations at surface soil was lower than at deeper depths (Figure 2) because of low precipitation in spring (Figure 1). It was suggested that both of two Salixshrubs increased WUE to adapt to drought. There was intra-species difference in WUE between the two Salixshrubs. The WUE of S. psammophilawas always higher than that of S. cheilophila(Figure 8), which is related to their eco-physiology. The xerophyte S. psammophilahas higher drought resistance than the mesophyte S. cheilophila. Further, the WUE of different shrubs is affected by their life form. The evergreen S. vulgarishad higher WUE than S. matsudanaand A. ordosicain Mu Us Sandy Land [12]. The long-term WUE of evergreen Ammopiptanthus mongolicus, N. tangutorumand C. korshinskiiwas higher than that of A. ordosicain Ulanbuh Desert [28]. In arid and semi-arid regions, shrubs with higher WUE may have more adaptability to extreme drought, resulting from global climate change. Moreover, the leaf δ13C value (−25.11‰ ‒ −27.28‰) of S. psammophilain Gonghe Basin is similar to its original distribution area (−26.75‰ ‒ −28.68‰, Wushen Banner, Ordos City) [34], which means that this shrub has adapted to the semi-arid climate in Gonghe Basin.

2.5. Conclusion

The water use strategy of four dominant desert shrubs was adapted to the semi-arid climate in Gonghe Basin. They used different water sources depending on their availability in different seasons, including shallow soil water recharged by rain, deep soil water recharged by ground water or ground water. They could use shallow soil water after rain in spring and summer. When shallow soil water was depleted, they turned to use deep soil water or ground water. The reliance of ground water was different for four shrubs in two habitats. Two shrubs in Caraganamainly depend on soil water and did not depend on ground water on sand dunes. C. intermediabarely used ground water, whereas C. korshinskiionly used ground water in spring, which accounted for 12.9% of its total water source. Two shrubs in Salixused ground water as an important stable water source on interdune. S. psammophilaalways used ground water in the growing season, which accounted for 13.1−16.1% of its total water source; whereas S. cheilophilaused ground water in spring and summer, which accounted for 22.6% and 15.6% of its total water source. Moreover, both of four shrubs increased long-term WUE in drought spring. Two shrubs in Caraganahad similar WUE in the growing season. However, the WUE of S. psammophilawas always higher than S. cheilophila, which means that the former might had more adaptability in Gonghe Basin.

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Acknowledgments

This study was supported by Chinese National Natural Science Foundation (41301095) and the Fundamental Research Funds for the Central Non-profit Research Institute of Chinese Academy of Forestry (CAFYBB2014QB023).

References

  1. 1. Ehleringer JR. Carbon and water relations in desert plants: an isotopic perspective. In: Ehleringer JR, Hall AE, Farquhar GD, editors. Stable Isotope and Plant Carbon–Water Relations. 1st ed. San Diego: Academic Press; 1993. p. 155–172. DOI: 10.1016/B978-0-08-091801-3.50018-0
  2. 2. Schwinning S, Starr BI, Ehleringer JR. Dominant cold desert plants do not partition warm season precipitation by event size. Oecologia. 2003;136:252–260. DOI: 10.1007/s00442-003-1255-y
  3. 3. Ogle K, Reynolds JF. Plant responses to precipitation in desert ecosystems: integrating functional types, pulses, thresholds, and delays. Oecologia. 2004;141:282–294. DOI: 10.1007/s00442-004-1507-5
  4. 4. Lin G. Stable Isotope Ecology. 1st ed. Beijing: Higher Education Press; 2013. 492 p.
  5. 5. Cheng X, An S, Li B, Chen J, Lin G, Liu Y, Luo Y, Liu S. Summer rain pulse size and rainwater uptake by three dominant desert plants in a desertified grassland ecosystem in northwestern China. Plant Ecology. 2006;184:1–12. DOI: 10.1007/s11258-005-9047-6
  6. 6. West AG, Hultine KR, Burtch KG, Ehleringer JR. Seasonal variation in moisture use in a piňon-juniper woodland. Oecologia. 2007;153:787–798. DOI: 10.1007/s00442-007-0777-0
  7. 7. Li S-G, Romero-Saltos H, Tsujimura M, Sugimoto A, Sasaki L, Davaa G, Oyunbaatar D. Plant water sources in the cold semiarid ecosystem of the upper Kherlen River catchment in Mongolia: a stable isotope approach. Journal of Hydrology. 2007;333:109–117. DOI: 10.1016/j.jhydrol.2006.07.020
  8. 8. Kowaljow E, Fernández RJ. Different utilization of a shallow-water pulse by six shrub species in the Patagonian steppe. Journal of Arid Environments. 2011;75:211–214. DOI: 10.1016/j.jaridenv.2010.10.004
  9. 9. Zhu Y, Jia Z, Yang X. Resource-dependent water use strategy of two desert shrubs on interdune, Northwest China. Journal of Food, Agriculture and Environment. 2011;9:832–835.
  10. 10. Kray JA, Cooper DJ, Sanderson JS. Groundwater use by native plants in response to changes in precipitation in an intermountain basin. Journal of Arid Environments. 2012;83:25–34. DOI: 10.1016/j.jaridenv.2012.03.009
  11. 11. Dai Y, Zheng X-J, Tang L-S, Li Y. Stable oxygen isotopes reveal distinct water use patterns of twoHaloxylonspecies in the Gurbantonggut Desert. Plant and Soil. 2015;389:73–87. DOI: 10.1007/s11104-014-2342-z
  12. 12. Ohte N, Koba K, Yoshikawa K, Sugimoto A, Matsuo N, Kabeya N, Wang L. Water utilization of trees in semiarid desert of Inner Mongolia, China. Ecological Applications. 2003;13:337–351. DOI: 10.1890/1051-0761
  13. 13. Pataki DE, Bush SE, Gardner P, Solomon DK, Ehleringer JR. Ecohydrology in a Colorado River riparian forest: implications for the decline ofPopulus fremontii. Ecological Applications. 2005;15:1009–1018. DOI: 10.1890/04-1272
  14. 14. Su H, Li Y, Liu W, Xu H, Sun OJ. Changes in water use with growth inUlmus pumilain semiarid sandy land of northern China. Trees: Structure and Function. 2014;28:41–52. DOI: 10.1007/s00468-013-0928-3
  15. 15. Song L, Zhu J, Li M, Yu Z. Water utilization ofPinus sylvestrisvar.mongolicain a sparse wood grassland in the semiarid sandy region of Northeast China. Trees: Structure and Function. 2014;28:971–982. DOI: 10.1007/s00468-014-1010-5
  16. 16. Liu S, Chen Y, Chen Y, Chen Y, Friedman JM, Hati JHA, Fang G. Use of 2H and 18O stable isotopes to investigate water sources for different ages ofPopulus euphraticaalong the lower Heihe River. Ecological Restoration. 2015;30:581–587. DOI: 10.1007/s11284-015-1270-6
  17. 17. Zhang D, Gao S, Shi M, Hasi E, Yan P, Lu R. Land Desertification and Its Control in Plateau of Qinghai. 1st ed. Beijing: Science Press; 2009. 194 p.
  18. 18. Phillips DL, Gregg JW. Source partitioning using stable isotopes: coping with too many sources. Oecologia. 2003;136:261–269. DOI: 10.1007/s00442-003-1218-3
  19. 19. Liu YX, editor. Flora in Desertis Reipublicae Populorum Sinarum. Tomus 2. 1st ed. Beijing: Science Press; 1987. 464 p.
  20. 20. Jia Z, Zhu Y, Liu L. Different water use strategies of juvenile and adultCaragana intermediaplantations in the Gonghe Basin, Tibet Plateau. PLoS One. 2012;7:e45902. DOI: 10.1371/journal.pone.0045902
  21. 21. Liu SW, editor. Flora Qinghaiica. Volume 1. 1st ed. Xining: Qinghai Pepole’s Publishing House; 1997. 544 p.
  22. 22. Liu J, He X, Bao H, Zhou C. Distribution of fine roots ofSalix psammophilaand its relationship with soil moisture in Mu Us Sandland. Journal of Desert Research. 2010;30: 1362-1366.
  23. 23. Ma YQ, editor. Flora Intramongolica. Volume 1. 1st ed. Huhhot: Inner Mongolia People Press; 1985. 294 p.
  24. 24. Yu Y, Jia Z, Zhu Y, Zhao S, Liu H, Li Q, Wei D. Root distribution ofSalix cheilophilaalong a chronosequence in high-cold sandland. Journal of Desert Research. 2014;34:67–74. DOI: 10.7522/j.issn.1000-694X.2013.00188
  25. 25. Chimner RA, Cooper DJ. Using stable oxygen isotopes to qualify the water source used for transpiration by native shrubs in San Luis Valley, Colorado USA. Plant and Soil. 2004;260:225–236. DOI: 10.1023/B:PLSO.0000030190.70085.e9
  26. 26. Yang H, Auerswald K, Bai Y, Han X. Complementarity in water sources among dominant species in typical steppe ecosystems of Inner Mongolia, China. Plant and Soil. 2011;340:303–313. DOI: 10.1007/s11104-010-0307-4
  27. 27. Xing X, Chen H, Zhu J, Chen T. Water sources of five dominant desert species in Nuomuhong area of Qaidam Basin. Acta Ecologica Sinica. 2014;34:6277–6286. DOI: 10.5846/stxb201310092427
  28. 28. Zhu Y, Jia Z, Lu Q, Hao Y, Zhang J, Li L, Qi Y. Water use strategy of five shrubs in Ulanbuh Desert. Scientia Silvae Sinicae. 2010;46:15–21. DOI: 10.11707/j.1001-7488.20100403
  29. 29. Wei YF, Fang J, Liu S, Zhao XY, Li SG. Stable isotope observation of water use source ofPinus sylvestrisvar.mongolicain Horqin Sandy Land, China. Trees: Structure and Function. 2013;27:1249–1260. DOI: 10.1007/s00468-013-0873-1
  30. 30. Gong G, Chen H, Duan D. Comparison of the methods using stable hydrogen and oxygen isotope to distinguish the water source ofNitraria tangutorum. Acta Ecologica Sinica. 2011;31:7533-7541
  31. 31. IPCC, editor. Climate Change 2013. The Physical Science Basis. New York: Cambridge University Press; 2013. 152 p.
  32. 32. West AG, Bowen GJ, Cerling TE, Ehleringer JR. Stable isotopes as one of nature’s ecological recorders. TRENDS in Ecology and Evolution. 2006;21:408-414. DOI: 10.1016/j.tree.2006.04.002
  33. 33. Cao S, Feng Q, Si J, Chang Z. Research on characteristics of water use efficiency variations ofPopulus euphraticaduring the growing season in extremely arid region of China. Journal of Desert Research. 2012;32:724–729.
  34. 34. Liu H, Li J, Zhao Y, Huang K. Study on δ13C values of desert plantSalix psammopphilaand water use efficiency. Arid Zone Research. 2008;25:514–518.

Written By

Yajuan Zhu

Submitted: October 27th, 2015 Reviewed: March 18th, 2016 Published: August 24th, 2016