Appendix D. Logistic regression results for the effect of phylogenetic distance (My), joint relative abundance (JRA), or the interaction (MyxJRA) on the probability that two plant species shared epifoliar fungal symbionts, from radial transects at San Lorenzo, Panama and Cape Tribulation, Australia.
Akaike Information Criterion (AIC), Likelihood Ratio (LR), P values of Wald test chi-square estimates for each factor, and percent concordance were used to select the best model for each site. At neither site did phylogenetic distance between plant species pairs contribute significantly to the model. Intercept was always significant (P ≤ 0.004 for all).
P values |
||||||||
Site |
Model |
AIC |
LR |
LR |
My |
JRA |
MyxJRA |
Conc.% |
| SanLorenzo | 1 |
787.4 | 18.7 | 0.0003 | 0.5426 | 0.0067 | 0.0532 | 61.4 |
| SanLorenzo | 2 |
789.3 | 14.8 | 0.0006 | 0.6816 | 0.0001 | 60.8 |
|
| SanLorenzo | 3 |
802 | 0.1 | 0.8379 | 0.8374 | 23.3 |
||
| SanLorenzo | 4 |
787.4 | 14.67 | 0.0001 | 0.0001 | 60.4 |
||
| SanLorenzo | 5 |
762.7 | 39.4 | 0.0001 | 0.0001† | 63.3 |
||
| CapeTrib | 1 |
796 | 27.2 | 0.0001 | 0.5328 | 0.1944 | 0.9277 | 63.6 |
| CapeTrib | 2 |
794 | 27.2 | 0.0001 | 0.4079 | 0.0001 | 63.7 |
|
| CapeTrib | 3 |
818.3 | 0.9 | 0.3407 | 0.3293 | 34.8 |
||
| CapeTrib | 4 |
792.7 | 26.6 | 0.0001 | 0.0001 | 62.7 |
||
| CapeTrib | 5 |
754.7 | 64.5 | 0.0001 | 0.0001† | 71.4 |
||
†Model uses log10(joint relative abundance).
At both sites, model 5 was the best, taking the form p(sharing) = expy / (1 + expy) where:
y = 2.0995 + 1.2722 log10JRA (for San Lorenzo)
y = 1.7059 + 1.1563 log10JRA (for Cape Tribulation).
To compare the logistic model predictions to the rates of fungal sharing observed at each site (Fig. 1), we grouped all pairwise joint relative abundances into log-series bins with lower bounds at 0.5x. In each bin, we calculated the proportion of plant pairs that shared fungal taxa.
San Lorenzo, Panama |
Cape Tribulation, Australia |
||||||
x |
Lower bound |
No. shared pairs |
No. total pairs |
Proportion shared |
No. shared pairs |
No. total pairs |
Proportion shared |
19 |
1.91E-06 |
0 |
0 |
0 |
55 |
2.85E-06 |
|
18 |
3.82E-06 |
0 |
0 |
0 |
110 |
5.71E-06 |
|
17 |
7.63E-06 |
0 |
0 |
1 |
133 |
3.42E-05 |
|
16 |
1.53E-05 |
6 |
351 |
0.0171 |
10 |
255 |
0.0001 |
15 |
3.05E-05 |
0 |
0 |
9 |
311 |
0.0005 |
|
14 |
6.10E-05 |
11 |
216 |
0.0509 |
9 |
271 |
0.0014 |
13 |
1.22E-04 |
42 |
683 |
0.0615 |
28 |
254 |
0.0048 |
12 |
2.44E-04 |
17 |
206 |
0.0825 |
14 |
199 |
0.0127 |
11 |
4.88E-04 |
20 |
130 |
0.1538 |
13 |
121 |
0.0308 |
10 |
9.77E-04 |
8 |
50 |
0.1600 |
13 |
76 |
0.0455 |
9 |
1.95E-03 |
4 |
13 |
0.3077 |
6 |
33 |
0.0634 |
8 |
3.91E-03 |
0 |
3 |
0.0000 |
4 |
10 |
0.0395 |
7 |
7.81E-03 |
0 |
1 |
0.0000 |
0 |
2 |
0.0174 |