Journal of Arid Land

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Effects of wetland connectivity on plant communities and vegetation patterns in the Qaidam Basin

YUE Yifan, MA Dengke, MA Yuanyuan, KANG Wenrong, ZHOU Guoying, ZHAO Wenzhi

干旱区科学, 2026, 18(4): 696-714. DOI: 10.1016/j.jaridl.2026.04.008

Sample	Dominant species	Life form	Density	Height (cm)	Crown width (cm)	Importance value
S1	Agropyron cristatum (L.) Gaertn.	Perennial herb	160	18.09±4.53	17.5±3.54	0.24
S1	Phragmites australis (Cav.) Trin. ex Steud.	Perennial herb	242	4.88±1.40	5.31±2.16	0.23
S2	Cyperus rotundus L.	Annual herb	430	6.67±3.06	3.00±0.58	0.38
S2	A. cristatum	Perennial herb	76	102.5±37.89	4.50±0.71	0.36
S3	Nitraria tangutorum Bobrov	Shrub	1	120.00±55.13	150.00±39.24	0.32
S3	C. rotundus	Annual herb	200	10.00±1.12	10.00±0.74	0.21
S4	Tamarix chinensis Lour.	Shrub	1	200.00±42.14	150.00±23.22	0.37
S4	P. australis	Perennial herb	150	160.00±10.13	30.00±5.24	0.21
S5	P. australis	Perennial herb	120	60.00±5.79	40.00±22.56	0.26
S5	Calamagrostis epigeios (L.) Roth	Perennial herb	100	150.00±26.28	30.00±9.86	0.31
S6	Apocynum venetum L.	Semi-shrub	49	73.13±15.26	42.67±7.53	0.66
S6	P. australis	Perennial herb	21	25.93±10.94	16.93±12.30	0.26
S7	T. chinensis	Shrub	3	200.00±50.00	260.00±69.28	0.34
S7	A. venetum	Semi-shrub	63	39.06±9.35	31.67±5.88	0.33
S8	P. australis	Perennial herb	370	113.33±29.55	45.33±13.60	1.00
S9	P. australis	Perennial herb	1760	47.65±22.05	25.56±9.38	0.63
S9	T. chinensis	Shrub	1	150.00±44.65	176.00±34.52	0.29
S10	T. chinensis	Shrub	3	200.00±64.38	350.00±77.84	0.40
S10	P. australis	Perennial herb	35	35.00±14.23	30.00±10.24	0.35
S11	P. australis	Perennial herb	740	65.67±23.42	17.94±7.04	1.00
S12	P. australis	Perennial herb	70	50.78±31.33	23.94±14.87	1.00
S13	P. australis	Perennial herb	97	22.36±7.68	7.90±5.24	0.30
S13	T. chinensis	Shrub	1	45.00±12.14	200.00±70.91	0.29

Table S2 Characteristics of wetland vegetation communities in the Qaidam Basin

本文的其它图/表

Fig. 2 Correlation analysis between the Index of Connectivity (IC) and wetland area
Fig. 8 Analysis of drivers for wetland vegetation characteristics in the Qaidam Basin using PLS-PM. (a), the loading value of each explanatory variable; (b), the direct and indirect effects of environmental variables on wetland ecosystems from the PLS-PM. AVE, average variance extracted; MAP, mean annual precipitation; MAT, mean annual temperature; PET, potential evapotranspiration. GOF, Goodness-of-Fit. ^**, significance at P<0.05 level; ^***, significance at P<0.01 level. Solid lines indicate significant relationships; and blue and red dashed lines indicate negative and positive insignificant relationships, respectively. The thickness of the line represents the strength of the causal relationship, supplemented by a standardized path coefficient.
Fig. 5 Spatial pattern of different wetland connectivity gradients
Fig. 3 Spatial distribution of different landscape
Table S1 Number of validation sampling sites and cartographic accuracy for each land cover type
Fig. 1 Sampling site locations of the wetlands in the Qaidam Basin (a) and representative landscape photographs of high- (b), moderate- (c), and low-connectivity (d) sites.
Table 1 Sampling sites division
Fig. 6 Comparative analysis of wetland vegetation community characteristics under different connectivity gradients. (a), fractional vegetation coverage (FVC); (b), Simpson's Dominance Index; (c), Pielou's Evenness Index; (d) Shannon-Wiener Diversity Index. The upper and lower boundaries of the box indicate the 25^th and 75^th percentiles, respectively; the bar is the standard deviation (SD); the horizontal line within each box indicates the median value; and the black line connects the mean values across analysis units; the symbol "×" indicates that only one species was recorded at that sampling site; and the point indicates the data of each sampling site. ns, non-significance; ^***, significance at P<0.01 level.
Fig. S1 Spatial distribution of validation sampling sites used for accuracy assessment. The survey route denotes the actual vehicle survey route conducted during field investigations in the Qaidam Basin from June to July in 2025.
Fig. S2 Frequency distribution histogram of IC values with connectivity classification based on the Jenks Natural Breaks method
Fig. 4 Determination of the optimal analysis unit. (a), variation characteristics of wetland landscape total area (TA); (b), stability analysis of first-order differences (ΔTA) across different analysis unit. CV, coefficient of variation.
Fig. 7 Characteristics of wetland vegetation pattern indices under different connectivity gradients. (a), class area (CA); (b), largest patch index (LPI); (c), area-weighted mean patch size (AREA_AM); (d), mean shape index (SHAPE_MN); (e), patch density (PD); (f), perimeter-area fractal dimension (PAFRAC); (g), mean contiguity index (CONTIG_MN); (h), mean Euclidean nearest-neighbor distance (ENN_MN); (i), aggregation index (AI).

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