Borges, P.A.V., Cardoso, P., Fattorini, S., Rigal, F., Matthews, T.J.,Di Biase, L., Amorim, I.R., Florencio, M., Borda-de-Água, L., Rego, C., Pereira, F., Nunes, R., Carvalho, R., Ferreira, M.T., Lopez, H., Pérez Delgado, A.J., Otto, R., Fernández Lugo, S., Nascimento, L. de, Caujapé-Castells, J., Casquet, J., Danflous, S., Fournel, J., Sadeyen, A.-M., Elias, R.B., Fernández-Palacios, J.M., Oromí, P., Thébaud, C., Strasberg, D. & Emerson, B.C. (2018) Community structure of woody plants on islands along a bioclimatic gradient. Frontiers of Biogeography, 10(3-4), 1-31. DOI:10.21425/F5FBG40295.
Understanding patterns of community structure and the causes for their variation can be furthered by comparative biogeographic analyses of island biotas. We used local scale woody plant data to investigate within- and between-island variations in species rarity and alpha, beta and gamma diversity in islands from three oceanic archipelagoes. We used standardized protocols to sample ten 50 m × 50 m forest plots in each of three islands with contrasting climate and regional species pools: Terceira (Azores), Tenerife (Canaries), and Reunion (Mascarene Islands). Occupancy frequency distributions and species abundance distributions were used to investigate rarity. The partitioning of beta diversity in a distance-decay framework was used to test for spatial patterns of community composition. Rarity was much more pronounced in the highly diverse islands of Tenerife and Reunion than in the regionally poorer island of Terceira. The number of species rose faster with increasing sample area in both Tenerife and Reunion. The slope of the species rank abundance curve was steeper in Terceira, whereas the richer island assemblages approached a lognormal model. Compositional changes according to spatial distance were mostly due to replacement of species in Terceira and Reunion. Our results point to important differences in the community structure of the regionally less diverse temperate island (Terceira) versus the two regionally highly diverse islands (Tenerife and Reunion).