Δ
13
C V ALUES OF SOIL ORGANIC CARBON AND THEIR 
RESPONSES TO C
3
 AND C
4
 PLANTS SHIFT IN MENGZI KARST 
GRABEN BASIN, SW CHINA
ODZIV VREDNOSTI Δ
13
C V ORGANSKEM OGLJIKU PRSTI  
NA SPREMEMBO SESTOJA RASTLIN C
3
 IN C
4
:  
PRIMER OBMOČJA MENGZI, JUGOZAHODNA KITAJSKA
Hui YANG
1,2
, Tongbin ZHU
1,2
, Farzaneh GAROUSI
1,2
, Qiang LI
1,2
 & Jianhua CAO
1,2
*
Abstract  UDC 631.417.1:581.5(510-14)
Hui Y ang, T ongbin Zhu, Farzaneh Garousi, Qiang Li & Jianhua 
Cao: δ
13
C values of soil organic carbon and their responses to 
C
3
 and C
4
 plants shift in Mengzi karst graben basin, SW China
Understanding the controlling factors of soil organic carbon 
isotope (δ
13
C
SOC
) change and the vegetation succession process 
is crucial to guide ecological restoration and agricultural culti-
vation in karst rocky desertification region. However, the infor-
mation about the combination of C
3
 and C
4
 plant distribution 
and rocky desertification remains unknown. Soils from different 
landforms, including basin, slope, and plateau, were sampled to 
investigate the spatial variance of the δ
13
C
SOC
 distribution charac-
teristics. The contribution of C
3
 and C
4 
plant species for δ
13
C
SOC
 
under the different rocky desertification grades (LRD: light rocky 
desertification; MRD: moderate rocky desertification; and SRD: 
severe rocky desertification) in Mengzi karst graben basin of 
Southwest (SW) China was also discussed. The δ
13
C
SOC
 value de-
creased with the increase of altitude from basin, slope to plateau. 
At the same landform, different rocky desertification grades had 
no significant effect on the δ
13
C
SOC
 in slope and plateau. Never-
theless, there were significant differences of δ
13
C
SOC
 between LRD 
and SRD in basin. The C
4
 plants account for more than 70% in 
the basin and slope, while C
3
 plants account for more than 70% in 
the plateau. This may be due to the long-term cultivation of corn 
in the historical period in the basin and slope. However, the pla-
teau area is not suitable for the growth of C
4
 plants such as corn 
due to cold climate. In addition, in the same landform, with the 
aggravation of rocky desertification, the proportion of C
4
 plants 
for δ
13
C
SOC
 increased with the proportion of C
3
 plants decreased. 
With the aggravation of rocky desertification, the composition 
of vegetation species changed from arbor (C
3
 plants) to small 
shrubs and herbs (C
4
 plants).
Key words: stable carbon isotope, rocky desertification, C
3
 and 
C
4
 plants, karst graben basin.
1
  Institute of Karst Geology, CAGS, Key Laboratory of Karst Dynamics, Ministry of Natural Resource & Guangxi, Guilin 541004, 
China, e-mails: yanghui-kdl@karst.ac.cn, ztb@karst.ac.cn, garousie393@gmail.com; liqiang@karst.ac.cn, jhcaogl@karst.ac.cn
2
  International Research Center on Karst, UNESCO, Guilin 541004, China.
*  Corresponding author
Received/Prejeto: 11.04.2019 DOI: 10.3986/ac.v49i1.7400
ACTA CARSOLOGICA 49/1, 109-118, POSTOJNA 2020
COBISS: 1.01
Izvleček UDK  631.417.1:581.5(510-14)
Hui Yang, Tongbin Zhu, Farzaneh Garousi, Qiang Li & Jian-
hua Cao: Odziv vrednosti δ
13
C v organskem ogljiku prsti na 
spremembo sestoja rastlin C
3
 in C
4
: primer območja Mengzi, 
jugozahodna Kitajska
Razumevanje povezave med spremembami izotopa v organ-
skem ogljiku v tleh (δ
13
C
SOC
) in procesi ekološke sukcesije je 
pomembno pri restavraciji in kultivaciji kraških degradiranih 
območij. O povezavi med porazdelitvijo sestoja rastlin C
3
 in C
4
 
ter skalno dezertifikacijo na kraških območjih vemo le malo. 
Prostorsko spremenljivost δ
13
C
SOC
 smo določali na različnih 
površinskih oblikah; v kotlini, na pobočjih in na kraški planoti 
na območju Mengzi v provinci Junan na jugovzhodu Kitajske. 
V vseh reliefnih oblikah smo obravnavali prispevek rastlinskih 
vrst C
3
 in C
4
 k vrednosti δ
13
C
SOC
. Posebno pozornost smo pos-
vetili tudi različnim stopnjam dezertifikacije (LRD: majhna; 
MRD: zmerna; in SRD: visoka). V splošnem vrednost δ
13
C
SOC
 
pada z naraščanjem nadmorske višine. Na planoti in pobočjih 
stopnja dezertifikacije ne vpliva pomembno na δ
13
C
SOC
, v kot-
lini pa je značilna razlika med območji z nizko stopnjo dez-
ertifikacije in območji z visoko stopnjo dezertifikacije. Sestoji 
rastlin C
4
 tvorijo več kot 70 % rastlinja v kotlini in na pobočjih, 
sestoji rastlin C
3
 pa 70 % rastlinja na planoti. Razlika je verjetno 
posledica pridelave koruze v kotlini in na pobočjih, saj planota 
zaradi hladne klime ni primerna za sajenje rastlin C
4
, kot je 
koruza. Sočasno z napredovanjem dezertifikacije upada delež 
rastlin C
4
 (npr. dreves) in narašča delež rastlin C
3
 (grmičevje 
in zeli).
Ključne besede: stabilni ogljikov izotop, skalna dezertifikacija, 
rastline C
3
 in C
4
, kraška kotlina.

HUI YANG, TONGBIN ZHU, FARZANEH GAROUSI, QIANG LI & JIANHUA CAO
INTRODUCTION
Soil organic carbon (SOC) mainly comes from the or-
ganic residues of terrestrial plants, especially decompo-
sition and metabolites of the roots, stems and leaves of 
higher plants (Bai et al. 2006). Soil organic carbon has a 
carbon isotopic composition comparable to that of the 
source plant material prior to humification (Schwartz et 
al. 1986), and every change in vegetation between C
3
 and 
C
4
 types could thus lead to a corresponding change in 
the 
13
C value of the SOC (δ
13
C
SOC
) (Schwartz et al. 1986). 
Three photosynthetic pathways exist among terrestrial 
plants: C
3
, C
4
, and crassulacean acid metabolism (CAM) 
photosynthesis (Ehleringer & Cerling 2002). Plants with 
C
3
, C
4
 and CAM photosynthesis have unique δ
13
C values 
which are not altered significantly during decomposition 
and soil organic matter formation (Boutton et al. 1998). 
Plants with C
3
 photosynthesis have δ
13
C values ranging 
from approximately -32 to -22‰ (mean ca. -27‰), while 
those with C
4
 photosynthesis have δ
13
C values rang-
ing from approximately -17 to -9‰ (mean ca. -13‰). 
Plants with obligate CAM have δ
13
C values similar to C
4
 
plants; however, those with facultative CAM may range 
from -30 to -10‰. It depends on the relative amount of 
carbon fixed by CAM vs. C
3
 photosynthesis (Griffiths, 
1992; Boutton et al. 1998). Consequently, δ
13
C
SOC
 values 
reflect the relative contribution of plant species with C
3
, 
C
4
 and CAM photosynthetic. It also reveals the pathways 
to community net primary productivity, the vegetation 
change, the organic matter turnover. From the perspec-
tive of earth critical zone (ECZ), δ
13
C
SOC
 avail to the 
understanding of earth-atmosphere-biosphere interac-
tions (Boutton et al. 1998). Therefore, the composition 
of δ
13
C
SOC
 is consistent with that of plants which form the 
source of organic matter (Bai et al. 2006). The stable car -
bon isotope ratio of SOC can be used to reconstruct the 
Fig. 1: Location of sampling sites in 
Mengzi county, Yunnan province.
ACTA CARSOLOGICA 49/1 – 2020 110

Δ
13
C V ALUES OF SOIL ORGANIC CARBON AND THEIR RESPONSES TO C
3
 AND C
4
 PLANTS SHIFT IN MENGZI  
KARST GRABEN BASIN, SW CHINA
vegetation dynamic process on the ecological and geo-
logical time scales. Studies on isotopic natural abundance 
have often been used to describe the dynamics of SOC 
(Balesdent et al. 1987; Desjardins et al. 1994; Ehleringer 
et al. 2000) or even to reconstruct vegetation changes 
over time (Boutton et al. 1998; Biedenbender et al. 2004; 
Xin et al. 2016).
The basin-mountain topography in the karst graben ba-
sin of Eastern Yunnan varies dramatically. The complex 
karst geo-environment factors (such as double-layer hy-
drogeological structure, the simultaneous droughts and 
floods, and the different maturity soil), and the adverse 
vegetation site conditions (such as the thin soil with lack 
of nutrients) induce serious rocky desertification (Cao 
et al. 2016). For the vegetation restoration of rocky de-
sertification, the plant community structure, the species 
diversity, the vegetation evolution and its driving mecha-
nism are the basic scientific points that aroused wide 
concern globally (Zhang et al. 2015; Wen et al. 2015; Wu 
et al. 2016; Wen et al. 2018). Nevertheless, few studies 
have been graded the combination of C
3
 and C
4
 plant dis-
tribution in rocky desertification area. In this paper, the 
carbon isotopic composition of SOC and its utilization in 
reconstructing vegetation are focused to provide theoret-
ical basis for selecting suitable species during vegetation 
restoration in rocky desertification area of graben basin.
STUDY AREA
The study site was located in Mengzi County, Yunnan 
Province of SW China (Fig. 1). It is characterized with 
the typical karst topography of mountains and basins. 
Large elevation differentiation and steep slopes in karst 
mountainous areas where the rocky desertification usu-
ally generated results in the special gradient effects of the 
water, energy, and the elements, as well as the climate, 
biology mass, and soil that important to vegetation (Li 
Fig. 2: Different examples of rocky 
desertification in basin, slope and 
plateau, where soil has been sam-
pled (Photo: H. Yang).
ACTA CARSOLOGICA 49/1 – 2020 111

2016). Soil samples were collected along the basin, slope, 
and plateau (Figs. 1 & 2). The annual average tempera-
ture of the basin, slope and plateau is 19.0, 15.6 and 13.7 
°C, respectively, and the annual rainfall of the basin, 
slope and plateau is 663, 575, and 1027 mm, respectively 
(Wang et al. 2019).
SOIL SAMPLING
Soil samples were collected from different landforms, in-
cluding basin (103°23’47”E, 23°28’22”N; elevation 1363 
m a.s.l.), slope (103°26’13”E, 23°27’43”N; elevation 1846 
m a.s.l.) and plateau (103°27’09”E, 23°27’08”N, elevation 
2086 m a.s.l.) (Fig. 2). The higher organic layer (topsoil) 
of 0–15cm was sampled. Different rocky desertification 
grades were selected in each landform: light, moderate 
and severe rocky desertification (hereby abbreviated as 
LRD, MRD and SRD). The classification method of rocky 
desertification was referred to Jiang et al. (2014). The de-
tails of the sampling sites, including the vegetation and 
rocky desertification, are shown in the reference Yang et 
al. (2019).
We totally gathered 51 soil samples. They represented 
the plots of the LRD, MRD, and SRD in every landform 
position. The sampling sites were beyond 100 m of dis-
tance in LRD, MRD, and SRD. At each site, 5 plots (1 m 
× 1 m) were randomly chosen at 20 m intervals. Sub-
samples were collected after removing of covering litter 
and homogeneously mixed into one sample on behaves 
of one site. Fresh soil was primary treated by stones and 
roots removal and then sieve to 2 mm. After that, they 
are air-dried for chemical analysis in laboratory. Three 
repeats were done for each sample during chemical 
analysis.
METHODS
Isotopic 
13
C/
12
C concentration was determined in a Flash 
1112A advantage auto analyzer coupled to a Delta V Ad-
vantage Isotope Ratio Mass Spectrometer (Thermo Sci-
entific, USA). The results of the isotopic analysis were 
expressed in units of δ (‰), determined in accordance 
with the international Pee Dee Belemnite (PDB) stan-
dard (Zhang et al. 2014) as in Eq. (1):
 
(1)
where δ
13
C is the isotopic composition, R
sample
 is the isoto-
pic ratio of 
13
C/
12
C of selected sample, and R
PDB
 is the ra-
tio of the international PDB standard. If the composition 
of organic matter in soil is known, the relative biomass 
of C
3
 and C
4
 plants in the surface vegetation can be esti-
mated according to the following isotope mass balance 
equation (Boutton et al. 1998):
 
(2)
 
(3)
where δ
13
C
SOM 
is the carbon isotope composition of soil 
organic matter; δ
13
C
3
 and δ
13
C
4
 are the average carbon 
isotope of C
3
 and C
4
 plants, generally -27‰ and -13‰ 
respectively (Boutton et al. 1998); C
3
(%) and C
4
(%) are 
the relative biomass of C
3
 and C
4
 plants respectively.
HUI YANG, TONGBIN ZHU, FARZANEH GAROUSI, QIANG LI & JIANHUA CAO
ACTA CARSOLOGICA 49/1 – 2020 112

RESULTS
ISOTOPE V ALUES OF SOC
The δ
13
C
SOC
 values in karst basin, slope and plateau are 
shown in Fig. 3. The isotopic composition of carbon pools 
varied greatly in the sampling area. Overall, the values of 
δ
13
C varied from -22.5‰ to -13.0‰, averaging -18.6‰. 
Furthermore, the range differed strongly between types 
of landform. With the increase of altitude, the δ
13
C
SOC
 be-
comes smaller. The values of δ
13
C
SOC
 varied from -22.5‰ 
to -18.3‰, averaging -20.7‰ in plateau. The δ
13
C
SOC
 
values in basin ranged from -18.2‰ to -13.0‰, averag-
ing -16.0‰, while δ
13
C
SOC
 values in slope ranged from 
-17.9‰ to -14.5‰, averaging -16.0‰. There is no sig-
nificant difference between δ
13
C
SOC
 in basin and slope, 
while there is significant difference between δ
13
C
SOC
 in 
basin and plateau.
In general, with the aggravation of rocky desertification 
at the same landform, δ
13
C
SOC
 value gradually increased 
(Tab. 1). Under the same rocky desertification grade, 
the isotope values gradually decreased with the increase 
of altitude, while the δ
13
C
SOC
 value of soil organic car-
bon in plateau is significantly different from other two 
locations.
VEGETATION CHANGES OF Δ
13
C
SOC
The relative biomass of C
3
 and C
4
 plants is shown in Fig. 
4. As can be seen from Fig. 4, C
4
 plants, as evident from 
δ
13
C‰, are dominant in basin and slope, while C
3
 plants 
are more abundant at the plateau. Under the same de-
gree of rocky desertification, C
3
 plants increased with 
the increase of altitude while C
4
 plants decreased. At the 
same landform, the proportion of C
3
 plants decreased 
with increase of rocky desertification in basin and at 
slope.
Tab. 1: Isotopic value of three rock desertification types (δ
13
C
SOC
 ‰).
Basin Slope Plateau
LRD -16.5±2.3 aA -16.7±1.0 aA -20.9±0.9 aB
MRD -15.4±0.9 abA -16.1±0.4 aA -21.1±0.7 aB
SRD -13.5±0.5 bA -15.2±0.6 aB -20.4±0.9 aC
Note: LRD, MRD and SRD represent the light, moderate and severe rocky desertification, respectively. Identical lowercase letters in the   
landform at the 0.05 level; Identical capital letters in the same row indicate no significant differences in the δ
13
C
SOC
 values under different 
landforms with the same grade of rocky desertification.
Fig. 3: Isotopic values (δ
13
C) in 
basin, slope and plateau posi-
tion.
Δ
13
C V ALUES OF SOIL ORGANIC CARBON AND THEIR RESPONSES TO C
3
 AND C
4
 PLANTS SHIFT IN MENGZI  
KARST GRABEN BASIN, SW CHINA
ACTA CARSOLOGICA 49/1 – 2020 113

THE RELATIONSHIP BETWEEN Δ
13
C
SOC
  
AND ENVIRONMENTAL V ARIABLES
The response of δ
13
C
SOC
 to the environmental variables 
(temperature, precipitation and altitude) was shown 
in Fig. 5a,b,c. In this study, statistical analysis results 
showed that there was a significant negative correlation 
between the annual average precipitation and δ
13
C
SOC
 
value (R
2
=0.90), while there was a positive correlation 
between the annual average temperature and δ
13
C value 
(R
2
=0.72), and a negative correlation between elevation 
and δ
13
C
SOC
 value (R
2
=0.70). The effects of environmental 
variables on δ
13
C
SOC
 of SOC could not be separated, and 
each response function of δ
13
C
SOC
 to an environmental 
variable included direct and indirect effects.
Fig. 4: The relative biomass of C
3
 
and C
4
 plants.
Fig. 5: The correlation between δ
13
C 
and precipitation (a), temperature 
(b) and elevation (c).
HUI YANG, TONGBIN ZHU, FARZANEH GAROUSI, QIANG LI & JIANHUA CAO
ACTA CARSOLOGICA 49/1 – 2020 114

DISCUSSION
SPATIAL PATTERN OF Δ
13
C
SOC
 AND ANALYSIS OF 
INFLUENCING FACTORS
It has been widely accepted that the stable isotope value of 
SOC is mainly controlled by vegetation type and biomass. 
There are also evidences that the topography, tempera-
ture, and precipitation can affect the stable isotope value 
of SOC (Wu et al. 1995; Bai et al. 2006; Li et al. 2009; Wen 
et al. 2018). Several studies reported variations of δ
13
C
4
 
along environmental gradients, e.g., a decrease in δ
13
C
4 
with increasing precipitation (Schulze et al. 1996), or, in 
contrast, an increase of δ
13
C
4 
with increasing soil water 
content (Chen et al. 2002). In this study, our results also 
confirm that δ
13
C
SOC
 decreases with the increase of pre-
cipitation. Furthermore, both of altitude and temperature 
are important factors that affect the stable isotope value 
of soil organic carbon. The absence of any relationship to 
climatic gradients in our data set may thus be caused by 
compensating effects (Auerswald et al. 2009).
VEGETATION CHANGES 
Most of the soil organic matter comes from the overly-
ing vegetation, and its carbon isotope value inherits the 
isotopic characteristics of the overlying vegetation (Liu & 
Huang 2008). Therefore, the carbon isotope of soil organ-
ic matter can well reflect the carbon isotope composition 
of the overlying vegetation during the pedogenesis pro-
cess (Zhang et al. 2015). The vegetation composition of 
Mengzi graben basin was a mixture of C
3
 and C
4
 plants, 
and its evolution responds to the change of rocky de-
sertification degree. The present data indicated that with 
the deterioration of rocky desertification, the proportion 
of C
4 
plants increased, while that of C
3 
plants increased. 
From the ecological point of view, forest succession is a 
dynamic process, where, some trees replace other trees, 
and one forest community replaces another forest com-
munity. Obviously, the continuous accumulation of δ
13
C 
of soil organic carbon is closely related to the succes-
sion process of regional forest communities, as well as 
the restoration and reconstruction process of degraded 
forest ecosystems (Huang et al. 2015). Previous studies 
showed that the destruction of native vegetation by hu-
man beings will lead to the increase of C
4
 plants, such as 
herbaceous plants (Boutton 1980). In this study, the eco-
logical environment and species composition of differ-
ent rocky desertification grades are different. The grade 
of LRD is dominated by shrubs and herbs, with a small 
number of trees; the MRD community is seriously de-
graded, and the community structure is characterized by 
sparse shrubs and grasses; in the SRD sample plot, a large 
number of rocks are exposed, the soil is shallow and the 
vegetation is sparse. Only a small number of tree seed-
lings and dwarf shrubs are scattered in the rocky crevices, 
and the areas with soil are mostly covered by herbaceous 
plants (Y ang et al. 2019).
In addition, the proportion of C
3
 plants in vegetation 
tends to increase with the increase of altitude, while C
4
 
plants in vegetation tend to decrease with the increase of 
altitude in this study. Studies have shown that the pro-
portion of C
4
 plants in vegetation tends to decrease with 
the increase of altitude, mainly occupying low-altitude 
areas, while C
3
 plants dominate high-altitude areas, and 
the transition zone between them occurs at about 1500–
3000m (Li et al. 2009). When the altitude exceeds 2000–
3000 m, the number of C
4
 plants in the plant population 
gradually decreases or even disappears (Boutton 1980; 
Rundel 1980; Cavagnaro 1988).
T emperature, precipitation and atmospheric CO
2
 content 
were considered as important factors to control carbon 
isotope and vegetation composition of terrestrial plants 
(Wang et al. 2014). Previous studies have confirmed that 
the temperature of plant growth season is more closely 
related to the occurrence of C
4
 plants, and C
4
 photosyn-
thetic pathway rarely occurs in areas where the average 
temperature of growth season is lower than 16 
o
C (Long 
1983). According to the research of Sage et al. (1999) on 
the distribution of C
4
 plants around the world, the key 
climate factor controlling the occurrence of C
4
 plants was 
the temperature in the growing season. The researchers 
also speculated that there was a temperature threshold 
for C
4
 plant growth (Long 1983; Sage et al. 1999).
CONCLUSION
In the present study, we quantified the spatial variance of 
the δ
13
C
SOC
 characteristics and the contribution of C
3
 and 
C
4
 plant species reflected by δ
13
C
SOC
 values under differ-
ent rocky desertification grades from different landforms 
(basin, slope and plateau) in Mengzi karst graben basin 
of Southwest China. The δ
13
C
SOC
 value decreased with 
the increase of altitude, specifically from basin, slope 
and plateau. Meanwhile, at the same landform, different 
Δ
13
C V ALUES OF SOIL ORGANIC CARBON AND THEIR RESPONSES TO C
3
 AND C
4
 PLANTS SHIFT IN MENGZI  
KARST GRABEN BASIN, SW CHINA
ACTA CARSOLOGICA 49/1 – 2020 115

rocky desertification grades had no significant effect on 
the δ
13
C
SOC
 in slope and plateau, while there were sig-
nificant differences of δ
13
C
SOC
 between LRD and SRD in 
basin. The C
4
 plants account for more than 70% in the 
basin and slope, while C
3
 plants account for more than 
70% in the plateau. This may be related to the long-term 
cultivation of corn in the historical period in the basin 
and slope. However, the plateau area is not suitable for 
the growth of C
4
 plants such as corn due to cold climate. 
In addition, in the same landform, with the aggravation 
of rocky desertification, the proportion of C
4
 plants in-
creased, while that of C
3
 plants decreased. This may be 
related to the increase of herbaceous plants with the ag-
gravation of rocky desertification. Although the present 
study focuses on δ
13
C
SOC
 characteristics and specifically 
its effects on the proportion of C
3
 and C
4
 plants in few 
soil samples and not on the high number of soil samples, 
more studies should investigate the potential influence 
of bedrock lithology on C
3
 and C
4
 plants under verti-
cal climate condition in karst graben basin. This result 
provides expanded guidance on the practice of ecologi-
cal restoration and agricultural cultivation in karst rocky 
desertification regions. For example, when conducting 
ecological restoration of rocky desertification in karst 
graben basins, we should consider not only the impacts 
of altitude and vertical climate, but also the distribution 
characteristics of C
3
 and C
4
 plants. Selecting suitable spe-
cies according to local conditions are of great significance 
for the promotion of ecological restoration in rocky de-
sertification areas.
ACKNOWLEDGEMENT
This study was supported by the National Key Research 
and Development Program of China under Grant No. 
2016YFC0502501, Natural Scientific Foundation under 
Grant No. 41571203 and No.41702281, Natural Scientific 
Foundation of Guangxi Zhuang Autonomous Region of 
China under Grant No.2017GXNSFAA198153 and Gui-
keAD19245176, and the Special Fund for Basic Scien-
tific Research of Institute of Karst Geology, CAGS (No. 
2020004).
REFERENCES
Auerswald, K., Wittmer, M.H.O.M., Männel, T.T., Bai, 
Y.F., Schäufele, R. & H. Schnyder, 2009: Large re-
gional-scale variation in C3/C4 distribution pattern 
of Inner Mongolia steppe is revealed by grazer wool 
carbon isotope composition.- Biogeosciences Dis-
cuss, 6, 545–574. DOI: 10.5194/bg-6-795-2009
Bai, S., Huang, C.M. & Y . Tang, 2006: Paleo-environmen-
tal implications of the stable carbon isotope in soil 
organic matter and its influencing factors.- Soils, 38, 
148–152. (in Chinese with English abstract)
Balesdent, J., Mariotti, A. & B. Guillet, 1987: Natural 
13
C 
abundance as a tracer for studies of soil organic 
matter dynamics.- Soil Biology and Biochemistry, 
19, 25–30. DOI: 10.1016/0038-0717(87)90120-9
Biedenbender, S.H., McClaran, M.P., Quade, J. & M.A. 
Weltz, 2004: Landscape patterns of vegetation 
change indicated by soil carbon isotope composi-
tion.- Geoderma, 119, 69–83. DOI: 10.1016/S0016-
7061(03)00234-9
Boutton, T.W., Archer, S.R., Midwood, A.J., Zitzer, S.F. 
& R. Bol, 1998: δ
13
C values of soil organic carbon 
and their use in documenting vegetation change in 
a subtropical savanna ecosystem.- Geoderma, 82, 
5–41. DOI: 10.1016/S0016-7061(97)00095-5
Boutton, T. W ., Harrison, A. T. & B. N. Smith, 1980: Dis-
tribution of biomass of species differing in photo-
synthetic pathway along an altitudinal transect in 
southeastern Wyoming grassland.- Oecologia, 45, 
287–298. DOI: 10.1007/BF00540195
Cao, J.H., Deng, Y ., Y ang, H., Pu, J.B., Zhu, T .B., Lan, F .N., 
Huang, F. & J.H. Liang, 2016: Rocky desertification 
evolution, treatment technology and demonstra-
tion in Karst faulted basins, Southwest China.- Acta 
Ecologica Sinica, 36, 7103–7108. (in Chinese with 
English abstract)
Cavagnaro, J. B., 1988: Distribution of C3 and C4 grasses 
at different altitudes in a temperate arid region of 
Argentina.- Oecologia, 76, 273–277. DOI: 10.1007/
BF00379962
Chen, S.P ., Bai, Y .F . & X.G. Han, 2002: V ariation of water-
use efficiency of Leymus chinensis and Cleistogenes 
squarrosa in different plant communities in Xilin 
HUI YANG, TONGBIN ZHU, FARZANEH GAROUSI, QIANG LI & JIANHUA CAO
ACTA CARSOLOGICA 49/1 – 2020 116

River Basin, Nei Mongol.- Acta Botanica Sinica, 44, 
1484–1490. DOI: 10.1016/S0032-9592(02)00188-7
Desjardins, T., Andreux, F., Volkoff, B. & C.C. Cerri, 
1994: Organic carbon and 
13
C contents in soils and 
soil size-fractions, and their changes due to defor-
estation and pasture installation in eastern Amazo-
nia.- Geoderma, 61, 103–118. DOI: 10.1016/0016-
7061(94)90013-2
Ehleringer, J.R., Buchmann, N. & L.B. Flanagan, 2000: 
Carbon isotope ratios in belowground carbon cycle 
processes.- Ecological Applications, 10, 412–422. 
DOI: 10.1890/1051-0761(2000)010[0412:CIRIBC]
2.0.CO;2
Ehleringer, J. R. & T.E. Cerling, 2002: C3 and C4 photo-
synthesis. In: H. A. Mooney & J. G. Canadell (eds.): 
Encoclopedia of Global Environmental Change.- John 
Wiley and Sons, Ltd., 186–190.
Griffiths, H., 1992: Carbon isotope discrimination and 
the integration of carbon assimilation pathways 
in terrestrial CAM plants.- Plant Cell and Envi-
ronment, 15, 1051–1062. DOI: 10.1111/j.1365-
3040.1992.tb01655.x
Huang, Z.S.,Yu, L.F., Fu, Y.H. & R.Yang, 2015: Charac-
teristics of δ
13
C value of soil organic carbon under 
naturally restoring degenerative karst forest.- Acta 
Pedologica Sinica, 52, 345–354. DOI:10.11766/
trxb201404180183
Jiang, Z., Lian, Y. & X. Qin, 2014: Rocky desertification 
in Southwest China: Impacts, causes, and restora-
tion.- Earth Science Review, 132, 1–12. DOI: doi.
org/10.1016/j.earscirev.2014.01.005
Li, G.P., 2016: Progress and prospects in research of 
mountain meteorogy in China during the past 25 
years.- Advances in Meteorological Science and 
Technology, 6, 115–122. (in Chinese with English 
abstract)
Li, J.Z., Wang, G.A., Liu, X.Z., Han, J.M., Liu, M. & X.J. 
Liu, 2009: Variations in carbon isotope ratios of 
C3 plants and distribution of C4 plants along an 
altitudinal transect on the eastern slope of Mount 
Gongga.- Science China Ser D-Earth Sciences, 39, 
1387–1396. DOI: 10.1007/s11430-009-0170-4
Liu, W.G. & Y.S. Huang, 2008: Reconstructing in-situ 
vegetation dynamics using carbon isotopic compo-
sition of biopolymeric residues in the central Chi-
nese Loess Plateau.- Chemical Geology, 249, 3/4, 
348–356. DOI: 10.1016/j.chemgeo.2008.01.010
Long, S. P., 1983: C4 photosynthesis at low tempera-
tures.- Plant Cell & Environment, 6, 345–363. DOI: 
10.1111/1365-3040.ep11612141
Rundel, P . W ., 1980: The ecological distribution of C3 and 
C4 grasses in the Hawaiian Islands.- Oecologia, 45, 
354–359. DOI: 10.1007/BF00540205 
Sage, R. F., Li, M. & R. K. Monson, 1999: The taxonomic 
distribution of C4 photosynthesis. In: Sage R.F. & 
R.K. Monson (eds.): C4 Plant Biology.- Acadimic 
Press, San Diego, 551–581.
Schulze, E. D., Ellis, R., Schulze, W., Trimborn, P. & H. 
Ziegler, 1996: Diversity, metabolic types and 
13
C 
carbon isotope ratios in the grass flora of Namibia 
in relation to growth form, precipitation and habi-
tat conditions.- Oecologia, 106, 352–369. DOI: 
10.1007/BF00334563
Schwartz, D., Mariotti, A., Lanfranchi, R. & B. Guillet, 
1986: 
13
C/
12
C Ratios of soil organic matter as indica-
tors of vegetation changes in the congo.- Geoderma, 
39, 97–103. DOI: 10.1016/0016-7061(86)90069-8
Wang, G., Zhang, L., Zhang, X., Wang, Y. & Y. Xu, 2014: 
Chemical and carbon isotopic dynamics of grass 
organic matter during litter decompositions: a lit-
terbag experiment.- Organic Geochemistry, 69, 
106–113. DOI: 10.1016/j.orggeochem.2014.02.012
Wang, S.N., Pu, J.B., Li, J.H., Zhang, T., Huo, W .J. & D.X. 
Y uan, 2019: Climatic characteristics under the influ-
ence of basin-mountain coupled topography and its 
influence on the ecological restoration of rocky de-
sertification in a Mengzi karst graben basin, South-
west China.- Carsologica Sinica, 38, 50–59. (in Chi-
nese with English abstract)
Wen, L., Song, T.Q., Du, H., Wang, K.L., Peng, W.X., 
Zeng, F.P ., Zeng, Z.X. & T.G. He, 2015: The succes-
sion characteristics and its driving mechanism of 
plant community in karst region, Southwest China.- 
Acta Ecologica Sinica, 35, 5822–5833. (in Chinese 
with English abstract)
Wen, P.C., Sheng, M.Y., Wang, L.J. & P. Wang, 2018: 
Temporal-spatial dynamics for plant community 
structure and species diversity of rocky desertifi-
cation ecosystem in karst plateau basin, southwest 
China.- Guihaia, 38, 11–23. (in Chinese with Eng-
lish abstract)
Wu, L.S., Cao, F.X., Peng, J.Q., Cao, J.W ., Xu, Y.F., Don,g 
X.J. & W. Xu, 2016: Plant community and species 
diversity in rocky desert areas of Southern Hunan.- 
Journal of Zhejiang A & F University, 33, 239–246. 
(in Chinese with English abstract)
Wu, N.Q., L,u H.Y. & X.J. Sun, 1995: Climatic factor 
tranfer from opal phytolith and its application in 
paleoclimate reconstruction of China loess-paleo-
sol sequence. Scientia Geologia Sinica, 1 (Suppl.), 
105–114.
Xin, X., Huiling, Z., Jianping, W ., Guowei, C., Guoyi, Z. & 
Z. Deqiang, 2016: 
13
C and 
15
N isotopic signatures of 
plant-soil continuum along a successional gradient 
in Dinghushan Biosphere Reserve.- Chinese Jour-
Δ
13
C V ALUES OF SOIL ORGANIC CARBON AND THEIR RESPONSES TO C
3
 AND C
4
 PLANTS SHIFT IN MENGZI  
KARST GRABEN BASIN, SW CHINA
ACTA CARSOLOGICA 49/1 – 2020 117

nal of Plant Ecology, 40, 533–542. (in Chinese with 
English abstract) DOI: 10.17521/cjpe.2015.0478
Yang, H., Zhang, P., Zhu, T., Li, Q. & J. Cao, 2019: The 
characteristics of soil C, N, and P stoichiometric ra-
tios as affected by geological background in a karst 
graben area, Southwest China.- Forests, 10, 601. 
DOI: 10.3390/f10070601
Zhang, C.Q., Wang, P.C., Long, C.L. & C. Yang, 2015: 
Species composition and biodiversity characteris-
tics in peak cluster-depressions differing in rock de-
sertification of a karst area in Guizhou.- Journal of 
Southwest University (Natural Science Edition), 37, 
48–53. (in Chinese with English abstract)
Zhang, H.Y., Lu, H.Y., Gu, Z.Y., Li, X.S., Zhang, Z.H., 
Chen, Y .Y ., Zhang, W .C., Lü, A.Q. & L.Y . Zhao, 2015: 
Organic matter stable isotopic composition of loess 
deposits in semiarid to humid climate regions of 
China and the vegetation variations since the last in-
terglaciation, Quaternary Sciences, 35, 4, 809–818. 
(in Chinese with English abstract) DOI: 10.11928/j.
issn.1001-7410.2015.04.03
Zhang, T., Cao, J.J., Chow, J.C., Shen, Z.X., Ho, K.F., Ho, 
S.S.H., Liu, S.X., Han,Y.M., Watson, J.G., Wang, 
G.H. & R.J. Huang, 2014: Characterization and sea-
sonal variations of levoglucosan in fine particulate 
matter in Xi’an, China.- Journal of the Air & Waste 
Management Association, 64,1317–1327. DOI: 
10.1080/10962247.2014.944959
HUI YANG, TONGBIN ZHU, FARZANEH GAROUSI, QIANG LI & JIANHUA CAO
ACTA CARSOLOGICA 49/1 – 2020 118