Heavy grazing led to the decrease of competitive intensity
relationships among dominant populations of clustered grasses in a
desert steppe
Zihan Wang1, Shijie Lv2,*, Hongmei
Liu3, Chen Chen1, Zhiguo
Li1, Zhongwu Wang1,*, Guodong
Han1
1 College of Grassland, Resources and Environment, Inner Mongolia
Agricultural University, Hohhot 010019, Inner Mongolia, P.R. China.
2 Science College, Inner Mongolia Agricultural University, Hohhot
010200, Inner Mongolia, P.R. China.
3 Forestry Research Institute of Inner Mongolia Autonomous Region,
Hohhot 010010, Inner Mongolia, P. R. China.
* Corresponding author email: wangzhongwu@imau.edu.cn ;lshj123@163.com .
Abstract: Stipa breviflora (Stipa breviflora Griseb.)
and Cleistogenes songorica (Cleistogenes songorica (Roshev.)
Ohwi) are two dominant species in the critically important desert steppe
of northern China. Under the interference of grazing, the two species
will have the phenomenon of plant cluster fragmentation to varying
degrees. Therefore, when the two plant populations appear in the same
plant community, what changes will happen in the inter-specific
relationship during grazing has important guiding significance for its
regulation of plant community and function. To study this, we observed
populations of wild S. breviflora and C. songorica in
field under a suite of grazing intensities and at a variety of scales.
The density changes of dominant species S. breviflora andC. songorica in desert steppe in Inner Mongolia were studied
under four grazing intensities (no grazing, CK, 0
sheep·ha-1·half year-1, light
grazing, LG, 0.93 sheep·ha-1·half
year-1, moderate grazing, MG, 1.82
sheep·ha-1·half year-1, heavy
grazing, HG, 2.71 sheep·ha-1·half
year-1) and six scales (5 cm×5 cm, 10 cm×10 cm, 20
cm×20 cm, 25 cm×25 cm, 50 cm×50 cm and 100 cm×100 cm). Results showed
that grazing changes the relationship between dominant species. With the
increase of grazing intensity, the densities of S. breviflora andC. songorica increased, and the increase was more obvious with
the increase of scale. Under heavy grazing conditions, the dominant
populations of clustered grasses in Inner Mongolia desert steppe
resisted the interference of high-intensity grazing by reducing
inter-specific competition ability (increasing inter-specific affinity).