Temporal and spatial responses of the branch and leaf growth relationship to human water flow regulation: a case study on remnant Myricaria laxiflora populations

Figures & data

Figure 1. Water level fluctuations and changes in exposure time and soil water content along sample transects. Soil water content in middle and upper parts of the fluctuation zone changes within a certain range with water level fluctuation, while soil water content in the lower part of the fluctuation zone decreases sharply with rapid decline of water level.

Figure 2. Allometric relationships between leaf number, leaf-and-branch volume, and leaf-and-branch water content with leaf-and-branch dry mass of M. laxiflora at different growth recovery times. Allometric relationship between leaf traits differs among different plant recovery times.

Table 1. Regression analysis of leaf trait relationships by standardized major axis estimation (SMA) at different recovery growths along elevation gradients. Relationship between leaf traits varies with recovery time and elevation gradient.

Water level gradient	Time (day)	LN vs. LM		LV vs. LM		LWC vs. LM
		Slope	R^2	Slope	R^2	Slope	R^2
Upper part	10	0.41 (0.20–0.86)	0.36	1.02 (0.68–1.53)	0.73	0.12 (0.06–0.26)	0.26
	20	0.47 (0.22,0.98)	0.32	1.20 (0.97,1.49)	0.92	0.10 (0.05–0.20)	0.21
	30	−0.46 (−0.95, −0.22)	0.27	1.02 (0.89,1.18)	0.97	0.11 (0.06,0.22)	0.17
	40	−0.43 (−0.89, −0.21)	0.45	1.12 (0.77,162)	0.78	0.24 (0.11,0.49)	0.13
	50	−0.74 (−1.08, −0.49)	0.76	0.97 (0.67,1.39)	0.79	−0.19 (−0.35, −0.11)	0.41
Middle part	10	0.49 (0.23,1.02)	0.32	0.92 (0.70,1.20)	0.88	−0.12 (−0.25, −0.05)	0.25
	20	0.97 (0.50,1.90)	0.22	1.46 (0.89,2.39)	0.60	0.12 (0.06,0.24)	0.24
	30	−0.83 (−1.76, −0.40)	0.33	0.96 (0.68,1.35)	0.81	−0.17 (−0.35, −0.08)	0.17
	40	0.49 (0.24,1.01)	0.32	1.01 (0.87,1.18)	0.96	0.09 (0.05,0.19)	0.31
	50	0.68 (0.37,1.24)	0.39	1.02 (0.83,1.26)	0.93	0.11 (0.07,0.18)	0.64
Lower part	10	0.42 (0.23–0.79)	0.32	0.88 (0.72,1.08)	0.94	−0.17 (−0.34, −0.09)	0.28
	20	−0.47 (−0.99, −0.23)	0.21	1.13 (0.79,1.63)	0.79	−0.08 (−0.15, −0.04)	0.36
	30	−0.59 (−1.22, −0.29)	0.17	1.28 (1.14,1.45)	0.97	0.10 (0.05,0.18)	0.28
	40	−0.41 (−0.85, −0.19)	0.23	1.39 (1.24,1.56)	0.95	−0.08 (−0.17, −0.04)	0.14
	50	0.20 (0.10,0.42)	0.13	1.17 (0.88,1.55)	0.87	−0.24 (−0.47, −0.12)	0.23
All	10	0.47 (0.32,0.68)	0.31	1.29 (1.00,1.67)	0.55	0.19 (0.13,0.27)	0.30
	20	0.63 (0.44,0.89)	0.26	1.11 (0.95,1.30)	0.83	0.09 (0.06,0.13)	0.26
	30	0.75 (0.52,1.08)	0.27	0.85 (0.66,1.09)	0.58	−0.19 (−0.27, −0.13)	0.13
	40	0.72 (0.53,0.98)	0.33	0.83 (0.65,1.06)	0.59	−0.25 (−0.35, −0.18)	0.28
	50	0.46 (0.32,0.66)	0.21	0.82 (0.69,1.04)	0.79	0.14 (0.10,0.21)	0.17

Note: LN, Leaf number; LV, Leaf-and-branch volume; LWC, Leaf-and-branch water content; LM, Leaf-and-branch dry mass; R², Determination coefficient; 95% confidence interval of slopes are shown in parentheses. Significant correlations were found between the two variables (p < 0.05).

Figure 3. Allometric relationships between leaf number, leaf-and-branch volume, and leaf-and-branch water content with leaf-and-branch dry mass of M. laxiflora along different water level gradients. Allometric relationship between leaf traits differs among water level gradients.

Table 2. Test for slope heterogeneity of leaf trait relationships and common slope for each water level gradient. Common slope varies among different water level gradients.

Water-level fluctuation zone	LN vs. LM			LV vs. LM			LWC vs. LM
	Common slope	Heterogeneity of slope	P	Common slope	Heterogeneity of slope	p	Common slope	Heterogeneity of slope	p
Upper part	−0.78 (−1.03, −0.58)	0.42	0.00	1.51 (1.23,1.86)	0.69	0.00	−0.22 (−0.30, −0.17)	0.31	0.00
Middle part	0.79 (0.61,1.03)	0.52	0.09	1.02 (0.87,1.19)	0.55	0.69	0.12 (0.09,0.17)	0.81	0.00
Lower part	0.53 (0.41,0.70)	0.29	0.00	—	0.02	—	−0.23 (−0.29, −0.17)	0.08	0.00
All	0.66 (0.56,0.77)	0.15	0.00	—	0.01	—	—	0.01	—

Note: p, Difference between slope and 1.0.