Fig 1.
Location of the nine islands in the Azorean archipelago, aligned in a WNW–ESE direction.
The study islands are highlighted (Flores, Faial, Terceira and Santa Maria), where a detail of the surface area occupied by native forests is also indicated in grey.
Fig 2.
Schematic representation of the sampling procedure.
Each line indicates each sampled transect, the blue boxes represent the four islands (Flores, Faial, Terceira and Santa Maria), and the colour boxes inside of each island represent each habitat (Native forest, Exotic forest, Semi-natural pasture, and Intensive pasture). We compared all transects at the archipelago level (four islands and four habitats together, n = 64 transects), and separately within each island alone (n = 16 transects), and also within each habitat considering the four study islands together (n = 16 transects).
Fig 3.
Averaged species richness per transect for each habitat type.
Box plot indicates the median, maximum, minimum, and upper and lower quartiles of the averaged species richness per transect calculated per each considered habitat: Native forest (NF), Semi-natural pastures (SNP), Exotic forest (EF), and Intensively managed pasture (IMP). Species richness of (a) indigenous and (b) exotic species were calculated using the 10 rarefied matrices.
Table 1.
Degree of nestedness independently calculated on each study island, indicating significant anti-nestedness.
Table 2.
Degree of nestedness calculated on each habitat considering the four study islands together, indicating significant anti-nestedness.
Table 3.
General increase in assemblage dissimilarity by the inclusion of exotic species into indigenous assemblages.