Pérez de Paz J, Caujapé-Castells J
Annals of Botany 2013 (in press)
• Background and Aims: We update the allozyme and reproductive datasets for the Canarian flora to (i) assess how the present levels and structuring of genetic variation have been influenced by the abiotic island traits and by phylogenetically determined biotic traits of the corresponding taxa; and (ii) suggest conservation guidelines.
• Methods: We conduct (i) Kruskal-Wallis tests to assess the relationships of 27 variables with genetic diversity (estimated by A, P, Ho and He) and structuring (GST) of 123 taxa representing 309 populations and 16 families (see http://www.demiurge-project.org/matrix_digests/D-ALLOZ-15); and (ii) multiple linear regression analyses (MLRA) to determine the relative influence of the less correlated significant abiotic and biotic factors on the genetic diversity levels.
• Conclusions: The interactions between biotic features of the colonizing taxa and the abiotic island features drive plant diversification in the Canarian flora. However, the lower weight of closeness to the mainland than of (respectively) high basic chromosome number, partial or total self-incompatibility and polyploidy in the MLRA indicates substantial phylogenetic constraint; the importance of a high chromosome number is feasibly due to the generation of a larger number of linkage groups, which increase gametic and genotypic diversity. Genetic structure is also more influenced by biotic factors (respectively long-range seed dispersal, basic chromosome number, and partial or total self-incompatibility) than by distance to the mainland. Conservation-wise, genetic structure estimates (FST/GST) only reflect endangerment under intensive population sampling designs, and neutral genetic variation levels do not directly relate either to threat status or to small population sizes. We emphasize habitat protection, but our results suggest the urgent implementation of elementary reproductive studies in all cases, and of ex situ conservation measures for the most endangered taxa, even without prior studies. In non-endangered endemics, multi-disciplinary research is needed before suggesting case-specific conservation strategies. Also of utmost importance, the molecular information relevant for conservation should be conserved in a standardized format to facilitate further insight.
