Genetic diversity and structure of the narrow endemic Seseli farrenyi (Apiaceae): implications for translocation.

Seseli farrenyi (Apiaceae) is an extremely narrow endemic plant, which is considered as one of the species of most conservation concern in Catalonia (NW Mediterranean Basin). Given the accelerated fragmentation and reduction of population size (of over 90%), the environmental agency of Catalonia is currently preparing a recovery plan that includes reinforcements of the extant populations. The present study is aimed at providing the necessary knowledge to carry out genetically-informed translocations, by using microsatellites as genetic markers. Fourteen microsatellites have been specifically developed for S. farrenyi, of which nine have been used. Besides the extant natural populations, the three ex situ collections that are known to exist of this species have also been studied, as they would be the donor sources for translocation activities. Our main finding is that levels of genetic diversity in the natural populations of S. farrenyi are still high (H e = 0.605), most likely as a result of a predominantly outcrossing mating system in combination with the limited time elapsed since the population decline. However, population fragmentation is showing the first genetic signs, as the values of genetic differentiation are relatively high, and two well-differentiated genetic lineages have been found even in such a narrow geographic range. These genetic results provide important information when designing conservation management measures.

Global distribution patterns and niche modelling of the invasive Kalanchoe × houghtonii (Crassulaceae).

Invasive alien species are currently considered one of the main threats to global biodiversity. One of the most rapidly expanding invasive plants in recent times is Kalanchoe × houghtonii (Crassulaceae), an artificial hybrid created in the 1930s in the United States by experimental crossings between K. daigremontiana and K. tubiflora, two species endemic to Madagascar. Thanks to its large colonizing capacity (mainly derived from the production of asexual plantlets), K. × houghtonii soon escaped from cultivation and quickly spread in many parts of the world. However, its actual range is not well known due to the lack of a formal description until recent times (2006) and its strong morphological resemblance with one of its parentals (K. daigremontiana). The present study was aimed, in the first instance, to delimit the present distribution area of K. × houghtonii at the global scale by gathering and validating all its occurrences and to track its colonization history. Currently, K. × houghtonii can be found on all continents except Antarctica, although it did not reach a global distribution until the 2000s. Its potential distribution, estimated with MaxEnt modelling software, is mainly centered in subtropical regions, from 20° to 40° of both northern and southern latitudes, mostly in areas with a high anthropogenic activity. Unexpectedly, concomitant to a poleward migration, future niche models suggest a considerable reduction of its range by up to one-third compared to the present, which might be related with the Crassulaceaean Acid Metabolism (CAM) of K. × houghtonii. Further research may shed light as to whether a decrease in potential habitats constitutes a general pattern for Crassulaceae and CAM plants.

Nuclear and plastid DNA phylogeny of tribe Cardueae (Compositae) with Hyb-Seq data: A new subtribal classification and a temporal diversification framework.

Classification of tribe Cardueae in natural subtribes has always been a challenge due to the lack of support of some critical branches in previous phylogenies based on traditional Sanger markers. With the aim to propose a new subtribal delimitation, we applied a Hyb-Seq approach to a set of 76 Cardueae species representing all subtribes and informal groups defined in the tribe, targeting 1061 nuclear conserved orthology loci (COS) designed for Compositae and obtaining chloroplast coding regions as by-product of off-target reads. For the extraction of the target nuclear data, we used two strategies, PHYLUCE and HybPiper, and 776 and 1055 COS loci were recovered with each of them, respectively. Additionally, 87 chloroplast genes were assembled and annotated. With three datasets, phylogenetic relationships were reconstructed using both concatenation and coalescent approaches. Phylogenetic analyses of the nuclear datasets fully resolved virtually all nodes with very high support. Nuclear and plastid tree topologies are mostly congruent with a very limited number of incongruent nodes. Based on the well-solved phylogenies obtained, we propose a new taxonomic scheme of 12 monophyletic and morphologically consistent subtribes: Carlininae, Cardopatiinae, Echinopsinae, Dipterocominae (new), Xerantheminae (new), Berardiinae (new), Staehelininae (new), Onopordinae (new), Carduinae (redelimited), Arctiinae (new), Saussureinae (new), and Centaureinae. In addition, we further updated the temporal framework for origin and diversification of these subtribes. Our results highlight the power of Hyb-Seq over Sanger sequencing of a few DNA markers in solving phylogenetic relationships of traditionally difficult groups.

Reinterpretation of an endangered taxon based on integrative taxonomy: The case of Cynara baetica (Compositae).

The Strait of Gibraltar, the gateway between the Atlantic Ocean and the Mediterranean Sea, has a convulsive geological history, with recurring closing and opening events since the late Miocene. As a consequence, this region has played a major role in the evolutionary history of many species. Cynara baetica (Compositae) is a diploid perennial herb distributed in both sides of this strait. It is currently subdivided into two subspecies: C. baetica subsp. baetica for the Spanish populations, and C. baetica subsp. maroccana for the Moroccan ones. Following three different approximations of species delimitation, including phylogenetic and population genetic analyses (based on three AFLP primer combinations and two intergenic spacers of cpDNA), ecological niche modeling (ENM) and morphological studies, this taxon is investigated and reinterpreted. The results obtained showed a clear genetic, morphological and ecological differentiation between the two taxa and the important role played by the Strait of Gibraltar as a geographical barrier. Based on this evidence, the current taxonomic treatment is modified (both taxa should recover their specific rank) and specific conservation guidelines are proposed for the newly delimited taxa.