Figure 1.
Location of study area in China.
The thin solid dark blue lines are isolines of mean annual precipitation. Triangles are sampling sites.
Figure 2.
Correlations between δ13C and δ15N values of the studied C3 (filled circles) and C4 plants (open circles).
Linear regression equations, R2 and P values are provided.
Table 1.
Degrees of freedom (df), F and P values from slope comparison analysis to assess differences in sensitivity between C3 and C4 species, as well as among the three studied shrubs: Nitraria sibirica (NS), Reaumuria soongorica (RS) and Hedysarum mongolicum (HM).
Figure 3.
Plant δ13C values (C3, filled circles; C4, open circles) as a function of mean annual precipitation.
Linear regression equations, R2 and P values are provided.
Figure 4.
Plant δ15N values (N2-fixing, open circles; AM, open triangles; Ecto, open squares; Non, filled circles) as a function of mean annual precipitation.
Linear regression equations, R2 and P values are provided.
Figure 5.
Leaf δ13C (a) and δ15N (b) values as a function of mean annual precipitation in Nitraria sibirica (circle, solid line), Reaumuria soongorica (square, dash line) and Hedysarum mongolicum (diamond, dotted line).
R2 and P values of linear correlations are provided.
Figure 6.
Soil organic matter δ13C (a) and δ15N (b) values as a function of mean annual precipitation.
Linear regression equations, R2 and P values are provided.