RESUMO
BACKGROUND AND AIMS: The hypothesis of an ancient introduction, i.e. archaeophyte origin, is one of the most challenging questions in phylogeography. Arundo donax (Poaceae) is currently considered to be one of the worst invasive species globally, but it has also been widely utilzed by man across Eurasia for millennia. Despite a lack of phylogenetic data, recent literature has often speculated on its introduction to the Mediterranean region. METHODS: This study tests the hypothesis of its ancient introduction from Asia to the Mediterranean by using plastid DNA sequencing and morphometric analysis on 127 herbarium specimens collected across sub-tropical Eurasia. In addition, a bioclimatic species distribution model calibrated on 1221 Mediterranean localities was used to identify similar ecological niches in Asia. KEY RESULTS: Despite analysis of several plastid DNA hypervariable sites and the identification of 13 haplotypes, A. donax was represented by a single haplotype from the Mediterranean to the Middle East. This haplotype is shared with invasive samples worldwide, and its nearest phylogenetic relatives are located in the Middle East. Morphometric data characterized this invasive clone by a robust morphotype distinguishable from all other Asian samples. The ecological niche modelling designated the southern Caspian Sea, southern Iran and the Indus Valley as the most suitable regions of origin in Asia for the invasive clone of A. donax. CONCLUSIONS: Using an integrative approach, an ancient dispersion of this robust, polyploid and non-fruiting clone is hypothesized from the Middle East to the west, leading to its invasion throughout the Mediterranean Basin.
Assuntos
DNA de Plantas/genética , Efeito Fundador , Haplótipos , Espécies Introduzidas , Dispersão Vegetal , Poaceae/fisiologia , Ásia , Evolução Biológica , Ecossistema , Marcadores Genéticos , Região do Mediterrâneo , Dados de Sequência Molecular , Filogenia , Poaceae/anatomia & histologia , Poaceae/genética , Polimorfismo Genético , Reprodução , Análise de Sequência de DNARESUMO
Background: Amongst the genus Rumina, R.paivae was decribed from North Africa for the first time by Lowe in 1861 on the basis of a limited number of samples. During the 19th and 20th centuries, it was described several times, under different names and different ranks leading to a taxonomic imbroglio before being forgotten. In 2002, Mienis rehabilitated R.paivae, but Prevot et al. (2013, 2014) considered it as a large phenotype of R.decollata Linnaeus (1758) on the basis of genetic and anatomical studies. New information: In this study, we present morphological and anatomical comparisons and differences between two groups of shells collected in France and considered as R.decollata. Using seven morphological characters related to the size and one to the microscopic sculptures of the shell and two related to the eggs and the colours of the morphs, we attribute these two groups to two morphologically described species: R.paivae and R.decollata. We propose a way to easily distinguish them from each other. With regard to their distribution, morphology and genetics, we discuss their relative systematic position. Moreover, in this study, we report for the first time R.paivae, a given north African taxa, in the south-ast of France, in Marseille.
RESUMO
Urbanization is one of the main threats to biodiversity. However, some urban green spaces could act as refuges for urban fauna if the composition of the flora were less horticultural and if a less intensive management strategy is adopted. Among the taxa, butterflies are experiencing a strong decline from European to regional scales. An ecological engineering project based on a plantation of host and nectariferous plants backed up by a well thought out management strategy was carried out in Marseille at the Parc Urbain des Papillons (the Butterflies Urban Park). We assessed its effectiveness by comparing the butterfly communities in this park before and after the engineering work, and we compared it to a neighboring wasteland with natural habitats. After 12 years of the project, the results show a significant change in the species composition. The species richness greatly increased from 25 to 42 species. Some specialist species we targeted appeared, and their numbers increased from one to five. However, three Mediterranean species are still absent compared to the wasteland with natural habitats. As the plant palette used and the management strategy implemented enabled us to significantly increase the number of species, we now plan to work on the structure of the vegetation.
RESUMO
Failure of seed production in the genus Arundo L. (Poaceae) is often attributed to polyploidy. This study tested the impact of two ploidy levels (2n=12 and 18x) on the fertility of four Mediterranean Arundo. Viable pollen was screened from its production to its germination, and seed occurrence was monitored in admixture or isolated conditions. In addition, insights on restructuration of polyploid genomes were analysed using molecular cytogenetics. Our results show that high ploidy levels do not automatically induce failure of sexual reproduction. The two ploidy levels are able to produce viable pollen and seed set depending on species and cultural conditions. The sterility of A. micrantha (2n=12x) and A. donax (2n=18x) is due to the early failures of gametogenesis steps. For 18x cytotypes of A. donaciformis and A. plinii, seed absence for isolated genotype vs. seed production in admixed culture support their auto-incompatibility.