Fig 1.
Overview diagrams of experimental site, alluvial fan and species types.
A: 200,000 m2 (400 m×500 m) sampling area of UAV, which includes four 20 m2 shrub and seven 4 m2 herbaceous community samples, respectively. SH-1, SH-2, SH-4 and SH-4 refer to herbaceous communities in washes, whereas H1, H2 and H3 are the herbaceous communities in non-washes areas. S1, S2, S3 and S4 are shrub community in washes. B: alluvial fan. C: shrub species. D: herbaceous species. Shrub is R. soongonica, whereas herbaceous include H. hispidus, S. kaschgaricum, P. harmala and S. capillata.
Fig 2.
Differences in abundance, species richness, plant height and crown area between washes and non-washes.
Different letters in the horizontal direction in each box indicate the significant differences in related variables between washes and non-washes, whereas the same letters show the insignificant difference. Values are shown as Mean±SE.
Table 1.
Summary of the descriptive statistics for the variables used in this study.
Wash width (m) and shrub growth characteristics are interpreted by 200, 000 m2, whereas diversity and herbaceous plants growth are calculated in 4 m2 UAV images. Plant growth characteristics include plant height (m) and crown area (m2). Descriptive statistics include Mean ± SD, maximum and minimum. F, T, and P-value are the results from independent sample t-test for the differences in diversity and plant growth condition between washes and non-washes. Different letters in the vertical direction with related variables indicate the significant differences between washes and non-washes, whereas the same letters show the insignificant difference.
Table 2.
Differences in soil properties between washes and non-washes.
Soil properties includes texture (i.e. sand, silt and clay) (%), the percentage of gravel content (%), soil bulk density (kg·m-3), soil organic carbon (g·kg-1), pH, soil electric conductivity (dS·m-1) and soil water content (%). F, T, and P-value are the statistical results of the independent sample t-test. Different letters in the horizontal direction with related variables indicate the significant differences in soil properties between washes and non-washes, whereas the same letters show the insignificant difference. Values are represented as Mean ± SD.
Table 3.
Differences in soil properties between narrower and wider positions of washes.
Soil properties include texture (i.e. sand, silt and clay) (%), the percentage of gravel content (%), soil bulk density (kg·m-3), soil organic carbon (g·kg-1), pH, soil electric conductivity (dS·m-1) and soil water content (%). F, T, and P-value are the statistical results of the independent sample t-test. Different letters in the horizontal direction with related variables indicate the significant differences in soil properties between narrower and wider positions of washes, whereas the same letters show the insignificant difference. Values are represented as Mean ± SD.
Fig 3.
Linear regression relationships of wash width of the ephemeral stream against plant height and crown area.
Regression equation, R2 and P-value are presented.
Fig 4.
Linear regression relationships of wash width of the ephemeral stream against the total number of individual plants, plant height and crown area per unit of washes.
Unit is the small grid with the length as 2 m, and the width as the actual wash width of the ephemeral stream. Length and width are located on the directions of stream flow and its perpendicular, respectively. Regression equation, R2 and P-value are presented.