Stipa breviflora
Grazing intensity, spatial scale and their interaction significantly
affected the density of S. breviflora population (Table 1,P < 0.05). The F value of spatial scale factors
on S. breviflora density was larger (F = 306.81),
indicating that the response of S. breviflora density to spatial
scale factors was more obvious than that of grazing intensity.
The changes of S. breviflora population density under different
grazing intensities and spatial scales are shown in Fig. 2. The density
of S. breviflora increased with the increase of grazing intensity
(Fig. 2A), and we observed significant pairwise differences between CK
and LG, CK and MG, CK and HG (P < 0.05), which also
indicated that the density of S. breviflora was different in LG
treatment , that is, the phenomenon of plant cluster fragmentation.
Although there was no significant difference between the LG, MG and HG
treatments we did observe a general trend of increasing density. The
error extension lines between each treatment were long, indicating that
the distribution of S. breviflora was highly variable within each
treatment. The density of S. breviflora increased exponentially
with the increase of spatial scale (Fig. 2B). Except for 5 cm×5 cm and
10 cm×10 cm, 20 cm×20 cm and 50 cm×50 cm, there were significant
differences between the two spatial scales(P < 0.05).
In fact, there is an exponential correlation between density and spatial
scale of S. breviflora (density of S. breviflora =
0.5314+0.0112×exp (1.4160×spatial scale of S. breviflora ),r 2 = 0.9995).
Table1 Variance analysis results for the Stipa
breviflora population