Table 3.
Permutational statistical analyses (PERMANOVA) of ascidian similarity among harbors according to their type (marina; marina and fishing, and marina, fishing and commercial) and geographic region (north: Girona; central: Barcelona; south: Tarragona)
| df | Abundance | Presence–absence | |||||||
|---|---|---|---|---|---|---|---|---|---|
| SS | pseudo-F | p value | Permdisp | SS | pseudo-F | p value | Permdisp | ||
| All species | |||||||||
| Region | 2 | 3,685.5 | 2.578 | 0.006 | 0.128 | 4,408 | 2.462 | 0.009 | 0.036 |
| Harbor type | 2 | 3,252.4 | 2.275 | 0.020 | 0.366 | 3,484.6 | 1.946 | 0.038 | 0.714 |
| Interaction | 4 | 3,384.8 | 1.184 | 0.287 | – | 4,879.6 | 1.363 | 0.138 | – |
| Residual | 23 | 16,440 | 20,588 | ||||||
| Introduced species | |||||||||
| Region | 2 | 3,759.8 | 3.306 | 0.003 | 0.308 | 3,871.8 | 4.513 | 0.004 | 0.249 |
| Harbor type | 2 | 2,513.2 | 2.210 | 0.042 | 0.190 | 3,871.8 | 4.513 | 0.004 | 0.249 |
| Interaction | 4 | 2,597.4 | 1.142 | 0.375 | – | 3,171.5 | 1.848 | 0.095 | – |
| Residual | 23 | 13,079 | 9,866.4 | ||||||
| Native species | |||||||||
| Region | 2 | 10,382 | 1.238 | 0.227 | – | 10,057 | 1.153 | 0.318 | – |
| Harbor type | 2 | 9,128.7 | 1.089 | 0.356 | – | 9,376.1 | 1.076 | 0.361 | – |
| Interaction | 2 | 9,485.8 | 1.132 | 0.347 | – | 9,390.6 | 1.077 | 0.378 | – |
| Residual | 8 | 33,533 | 34,867 | ||||||
Analyses were performed for abundance (Bray-Crutis index) and presence–absence (Jaccard index) data, and for the global dataset (32 harbors), the introduced species dataset (32 harbors), and the native species dataset (15 harbors). PERMISP probabilities of homogeneity of dispersion were also given for significant factors