Table 2. Results of GLMMs (model fit by maximum likelihood, Laplace approximation) containing pair-wise contrasts for the main plant species (standardized absolute cover, see Methods) of the vegetated area at each study site.
| Response variable | Contrast effects | Estimate | SE | t value | p |
|---|---|---|---|---|---|
| A. chamissonis | Be-Rv | 0.0210 | 0.0157 | 1.34 | 0.185 |
| Be-Sw | -0.0168 | 0.0157 | -1.068 | 0.288 | |
| Rv-Sw | -0.0378 | 0.016 | -2.404 | <0.05 | |
| Time | 0.0042 | 0.003 | 1.70 | 0.093 | |
| Transect (random effects): var = 5.2e-4, SD = 0.023 | |||||
| full model: Ambrosia~Site+Time+(1|Transect), family = gaussian; AIC = 241.35 | |||||
| M. chamomilla | Be-Rv | -0.0131 | 0.0022 | -5.853 | <0.001 |
| Be-Sw | -0.0126 | 0.0022 | -5.623 | <0.001 | |
| Rv-Sw | 0.0005 | 0.0022 | 0.231 | 0.818 | |
| Time | -0.0002 | 0.0003 | -0.518 | 0.602 | |
| Transect (random effects): var = 7.2e-6, SD = 0.003 | |||||
| full model: Matricaria~Site+Time+(1|Transect), family = gaussian; AIC = -686.2 | |||||
| R. maricola | Be-Rv | -0.0110 | 0.0035 | -3.12 | <0.01 |
| Be-Sw | -0.0090 | 0.0035 | -2.55 | < 0.01 | |
| Rv-Sw | 0.0000 | 0.0006 | 0 | 1 | |
| Time | 0.0004 | 0.0006 | 0.741 | 0.460 | |
| Transect (random effects): var = 0, SD = 0 | |||||
| full model: Rumex~Site+Time+(1|Transect), family = gaussian; AIC = -593.44 | |||||
| Atriplex spp. | Be-Rv | -0.028 | 0.008 | -3.582 | <0.001 |
| Be-Sw | -0.007 | 0.0077 | -0.904 | 0.368 | |
| Rv-Sw | 0.0206 | 0.0077 | 2.678 | <0.01 | |
| Be*Ti—Rv*Ti | 0.0037 | 0.0014 | 2.72 | <0.001 | |
| Be*Ti—Sw*Ti | 0.0014 | 0.0014 | 1.028 | 0.306 | |
| Rv*Ti—Sw*Ti | -0.0023217 | 0.00137 | -1.694 | 0.0933 | |
| Transect (random effects): var = 4.7e-6, SD = 0.002 | |||||
| full model: Atriplex~Site*Time+(1|Transect), family = gaussian; AIC = -589.01 | |||||
| S. americanus | Be-Rv | 0.0129 | 0.0052 | 2.496 | <0.05 |
| Be-Sw | 0.0130 | 0.0051 | 2.52 | < 0.05 | |
| Rv-Sw | 0.000 | 0.005 | -0.02 | 0.982 | |
| Be*Ti—Rv*Ti | -0.0042771 | 0.0009 | 4.65 | <0.001 | |
| Be*Ti—Sw*Ti | -0.0043 | 0.001 | -4.73 | <0.001 | |
| Rv*Ti—Sw*Ti | 0.0001 | 0.0009 | 0.076 | 0.940 | |
| Transect (random effects):var = 6.6e-7, SD = 0.001 | |||||
| full model: Scoenoplectus~Site*Time+(1|Transect), family = gaussian; AIC = -676.16 | |||||
| Hordeum spp. | Be-Rv | 0.0022 | 0.0013 | 1.68 | 0.0968 |
| Be-Sw | 0.0022 | 0.0013 | 1.68 | 0.097 | |
| Rv-Sw | 0.0000 | 0.001 | 0 | 1 | |
| Be*Ti—Rv*Ti | -0.0008 | 0.0002 | -3.49 | <0.001 | |
| Be*Ti—Sw*Ti | -0.0008 | 0.0002 | -3.49 | <0.001 | |
| Rv*Ti—Sw*Ti | 0.0000 | 0.0002 | 0 | 1 | |
| Transect (random effects): var = 0, SD = 0 | |||||
| full model: Hordeum~Site*Time+(1|Transect), family = gaussian; AIC = -976 | |||||
Models included site (B: unarmoured beach, Rv: revetment and Sw: seawall) as a fixed factor, time (9 dates) as a covariate, and random effects were associated with transects as a grouping factor. The best fitted full model is indicated per response variable. SE: standard error; var: variance; SD: standard deviation; AIC: Akaike’s information criterion. Significant effects appear in bold.