Taxonomy, systematics and conservation status of Centaurea veneris (Asteraceae), a cliff dwelling Ligurian endemic species

Antonio Giacò ¹, Samuele Maestri ¹, Andrea Coppi ², Lorenzo Peruzzi ¹

University of Pisa, Pisa, Italy ¹, University of Firenze, Firenze, Italy ²

Centaurea veneris (Sommier) Bég. (Asteraceae) is a cliff dwelling diploid species endemic to the promontory of Portovenere and the islands of Palmaria, Tino, and Tinetto (western Liguria, Italy). Traditionally, it was included in the C. cineraria L. group, but previous population genetic studies showed a close relationship with western Ligurian populations of C. aplolepa Moretti, a diploid species endemic to central and northern Italy. To verify the taxonomic position of C. veneris and the biosystematic relations with C. aplolepa, we conducted an integrative taxonomic investigation involving both morphometric and AFLP population genetic analyses. We sampled two populations of C. veneris, one at the Palmaria island and one at Portovenere. In this latter location, at less than 100 m from the collection site of C. veneris, we sampled also a population of C. aplolepa subsp. levantina Arrigoni. Then, two additional populations of C. aplolepa were sampled in western Liguria at Sestri Levante (C. aplolepa subsp. levantina) and at Bocca di Magra (C. aplolepa subsp. lunensis (Fiori) Dostál). For each population, 10–30 individuals for morphometrics and 10–14 individuals for population genetics were sampled. Both morphometric (PCA, univariate analyses and boxplots) and population genetic analyses (AMOVA, PCoA and structure analysis) confirm the taxonomic status of C. veneris as an evolutionary close but distinct species with respect to C. aplolepa. However, the genetic structure analysis detected slight levels of admixture in some individuals of C. veneris from Portovenere, possibly suggesting introgression with C. aplolepa. This hypothesis seems to be confirmed by some individuals of both species from this latter location showing an intermediate morphology. Thanks to the field observations and the new data produced, it is also possible to confirm the conservation status of C. veneris as a near threatened (NT) species. Indeed, due to the small distribution range and some threats (e.g., climate change and grazing by goats), this species nearly satisfies the criterion B (Geographic range) of IUCN for critically endangered (CR). However, the levels of heterozygosity detected in both populations of C. veneris suggest that this narrow endemic species does not suffer of low genetic variability. Thus, unless new threats would endanger this species in the near future, an imminent decline due to population dynamics is unlikely.

Main author career stage: Postdoc / Fellow

Contribution type: Talk

First choice session: 1. Systematics, phylogenetics, biogeography and evolution

Second choice session: 1. Systematics, phylogenetics, biogeography and evolution