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Maytenus senegalensissubsp.europaeacommunities are unique vegetal formations in Europe. In fact, they are considered Priority Habitat by Directive 92/43/EEC. These are ecologically valuable plant communities found in the southeast of Spain. By combining modeling methods of environmental variables, historical photo-interpretation, and fieldwork, a chronosequence of the evolution of their extent of occurrence (EOO) has been reconstructed in 1957 and 2011. Results showed a strong regression range ofM. senegalensissubsp.europaeapopulations. More than 26,000 ha of EOO for this species have been lost in the province of Almería. Considering the final number of polygons, this area has been fragmented 18 times since the 1950s. These results reinforce the idea that the alteration and fragmentation of habitat due to human activities is one of the most important drivers of biodiversity loss and global change. These activities are mostly intensive greenhouse agriculture and urbanization without sustainable land planning. Knowledge about the distribution ofM. senegalensissubsp.europaeais of great interest for future habitat restoration. Therefore, this would be the key species to recover these damaged ecosystems. [ABSTRACT FROM AUTHOR]

Habitats with alkaline edaphic substrates are often associated with plant speciation and diversification. The tribe Alysseae, in the family Brassicaceae, epitomizes this evolutionary trend. In this lineage, some genera, like Hormathophylla, can serve as a good case for testing the evolutionary framework. This genus is centered in the western Mediterranean. It grows on different substrates, but mostly on alkaline soils. It has been suggested that diversification in many lineages of the tribe Alysseae and in the genus Hormathophylla is linked to a tolerance for high levels of Mg+2 in xeric environments. In this study, we investigated the controversial phylogenetic placement of Hormathophylla in the tribe, the generic limits and the evolutionary relationships between the species using ribosomal and plastid DNA sequences. We also examined the putative association between the evolution of different ploidy levels, trichome morphology and the type of substrates. Our analyses demonstrated the monophyly of the genus Hormathophylla including all previously described species. Nuclear sequences revealed two lineages that differ in basic chromosome numbers (x = 7 and x = 8 or derived 11, 15) and in their trichome morphology. Contrasting results with plastid genes indicates more complex relationships between these two lineages involving recent hybridization processes. We also found an association between chloroplast haplotypes and substrate, especially in populations growing on dolomites. Finally, our dated phylogeny demonstrates that the origin of the genus took place in the mid-Miocene, during the establishment of temporal land bridges between the Tethys and Paratethys seas, with a later diversification during the upper Pliocene., Competing Interests: The authors have declared that no competing interests exist.