Plastid phylogeography of Delphinium fissum subsp. sordidum and the series Fissa (Ranunculaceae) in the Iberian Peninsula: implications for conservation

ABSTRACT

We study the phylogeography of the series Fissa species in the Iberian Peninsula. This group constitutes a complex formed by three Iberian endemic and threatened taxa with restricted distribution ranges and relatively small population sizes. We amplify and sequence two plastid regions, trnS-trnG and psbA-trnH from 15 sampling locations (n = 45). A total of 15 haplotypes are detected. The median-joining phylogenetic network shows two main haplotype lineages: one western corresponding to the western taxon, D. fissum subsp. sordidum, and the other eastern corresponding to eastern taxa D. bolosii and D. mansanetianum. AMOVA analysis with 94.32% of the total variation and SAMOVA analysis with a Fct value of 0.943 support the presence of these well-defined lineages. We report high values of total gene diversity (h_T = 0.959). Haplotype diversity within populations is low (h_S = 0.311). On the contrary, differentiation among populations (G_ST = 0.675) and Fixation Index (F_ST = 0.989) are high. These values mean that gene flow among populations is limited. Estimation of divergence times shows that the split between D. fissum subsp. sordidum and the two other taxa (D. bolosii and D. mansanetianum) took place during the transition between Pliocene and Pleistocene (approximately 2.67 Ma). Negative Tajima’s D-values test (Tajima’s D = -0.108, P ≥ 0.1) and unimodal mismatch distribution suggest expansion range for D. fissum subsp. sordidum. We advocate to draw up recovery plans for series Fissa species in the Iberian Peninsula, especially for D. fissum subsp. sordidum.

KEYWORDS:

• Delphinium series Fissa
• genetic diversity
• cpDNA
• haplotype network
• divergence time estimation
• conservation genetics
• biodiversity conservation

Acknowledgments

The authors thank to Maria Bosch for indicating us the accurate geographical coordinates to locate the populations of Ulldemolins and Rubió de Baix (Catalonia province), to António Maria Luis Crespí, João Rocha and Giacomo Colombo for helping us to collect leaf material of the D. bolosii populations and to Jesús Riera for collecting material of Delphinium mansanetianum. We are also grateful to four anonymous reviewers and the associate editor, Florian Jabbour, whose relevant suggestions greatly improved the quality of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Notes on contributors

Rubén Ramírez-Rodríguez

Rubén Ramírez-Rodríguez, PhD Biologist at the University of Salamanca (Spain); sample collection, wrote the manuscript, discussed the results and revised and approved the final draft of the manuscript.

Juan Francisco Jiménez

Juan Francisco Jiménez, Professor at the University of Granada (Spain); performed the experiments and analised the data, discussed the results and revised and approved the final draft of the manuscript.

Francisco Amich

Francisco Amich, Professor at the University of Salamanca (Spain); sample collection, discussed the results and revised and approved the final draft of the manuscript.

Pedro Sánchez-Gómez

Pedro Sánchez-Gómez, Professor at the University of Murcia (Spain): discussed the results and revised and approved the final draft of the manuscript.