Comparison of soil respiration among three different subalpine ecosystems on eastern Tibetan Plateau, China

Figures & data

Figure 1 (a) Location of Gongga Mountain, (b) map of eastern slope of Gongga Mountain and (c) location of study sites.

Figure 2 Mean monthly air temperature (°C) and mean monthly precipitation (mm) during the study period. Data were collected at the Meteorological station of Gongga Mountain, China.

Table 1 Main properties of topsoil in primary forest, secondary forest and clear-cut land on Gongga Mountain, China

	Primary forest	Secondary forest	Clear-cut land
ST (°C)	5.5^a	6.4^a	8.9^a
SM(%)	23.9^a	15.8^c	21.0^b
SOC(%)	29.7^a	24.5^b	15.0^c
Total N(%)	1.9^a	1.3^bc	0.7^c
pH	4.1^b	6.5^a	6.8^a
Bulk density (g cm^−3)	0.12^b	0.15^b	0.26^a

Note: ST, soil temperature; SM, soil moisture; SOC, soil organic carbon; Total N, total nitrogen. Numbers with the same letter (a, b, c) are not significantly different at p = 0.05. All values were annual average value.

Figure 3 Comparison between daytime average soil respiration (R_S) calculated from three measurements during 08:00–14:00 and diurnal average calculated from 12 measurements in a day.

Figure 4 Diurnal variation of soil respiration and soil temperature at 5 cm depth for primary forest, secondary forest and clear-cut land on Gongga Mountain, China.

Figure 5 Temporal dynamics of soil respiration, soil temperature and soil moisture for primary forest, secondary forest and clear-cut land on Gongga Mountain, China.

Table 2 Two-way analysis of variance (ANOVA) of soil respiration by site and measuring date

Source of variation	DF,degree of freedom	MS, mean square	F	P-value
Site	2	57.2	22	< 0.0001
Measuring date	39	14.1	5.4	< 0.0001

DF, degree of freedom; MS, mean square.

Figure 6 Relationship between soil respiration and soil temperature at 5 cm depth for primary forest, secondary forest and clear-cut land on Gongga Mountain, China.

Table 3 Values of regression coefficient and R² in models for relationships between soil respiration (R_S) and soil temperature (ST), soil moisture (SM), and ST-SM

	ST				SM	ST-SM
Site	α	β	R^2	Q10	R^2	R^2
Primary forest	1.3	0.13	0.61	3.7	0.22	0.62
Secondary forest	0.8	0.11	0.58	3.0	0.39	0.65
Clear-cut land	0.37	0.19	0.55	6.7	0.16	0.58

Figure 7 Relationship between soil respiration and soil moisture for primary forest, secondary forest and clear-cut land on Gongga Mountain, China.

Figure 8 (a) Relationship between soil temperature (ST) and soil organic carbon (SOC); (b) relationship between annual soil respiration (R_S) and SOC. CO₂, carbon dioxide.