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Aims In view of the growing interest in modelling the potential spread of invasive species, prediction of plant invasiveness on the basis of native range size holds considerable promise. Our objective was to use a simple model to evaluate whether a wider native range predisposes plant species to become invasive in non-native regions and to easily identify potential invaders on this basis. The Kashmir Himalayan alien flora, of which a large proportion is native to Europe, was used to test this model. Methods The Kashmir Himalayan alien flora comprises 436 species of vascular plants at different stages of invasion. We focussed on plant species at two critical invasion stages (sensu Colautti and MacIsaac 2004), i.e. Stage II (species that are just at the earliest phase of introduction) and Stage V (species that are widespread and dominant in the invaded region and are thus considered invasive). We used the territorial distribution in Europe (number of countries) as a surrogate for the native range size of plants of European origin. Important Findings Using a subset of 88 species, for which information on the native European range was available, we showed that a large proportion (68%) of Stage II species growing in the Kashmir Valley had a relatively restricted European range (present in ≤20 countries); on the other hand, 77% of Stage V species had an extensive native range (present in >20 countries). We consequently hypothesized that 14 Kashmir Himalayan Stage II species of European origin that are distributed in >20 European countries are at risk of becoming future invaders in Kashmir. On the other hand, those Kashmir Himalayan Stage II species of European origin distributed in ≤20 European countries are less likely to become invasive. Although this analysis is quite simple, the data suggest that a wider native range is a good predictor of plant invasiveness and could be used as a simple and low-cost early warning tool in predicting potential invasive species. [ABSTRACT FROM PUBLISHER]

Abstract: Whilst the importance of arbuscular mycorrhizal fungi (AMF) in invasive spread of some alien plant species has been recently established, it is unclear how such plants respond to AMF from different geographical sources. Besides, influence of different co-occurring plant species on the AMF-mediated invasiveness of alien species, though rarely investigated, is pivotal to the explicit understanding of the feedback between arbuscular mycorrhizal fungi and alien plant invasions. We therefore examined the influence of local (Kashmir Himalyan isolates) and foreign (isolates from Rajasthan, India) AMF on invasiveness of alien Anthemis cotula vis-à-vis the effect of three common co-occurring neighbours, Conyza canadensis, Galinsoga parviflora and Sisymbrium loeselii. Field studies revealed high incidence of Arum-type mycorrhizal colonization in natural populations of A. cotula and the pot trials confirmed the reliance of its invasiveness on AMF with the more favourable effect of local than foreign AMF. The mycorrhizal colonization intensity in field populations of A. cotula was strongly influenced by neighbour identity with major reduction recorded in the presence of S. loeselii (a cruciferous non-host) in comparison to other con-familial neighbours. Pot experiments confirmed the differential effect of co-occurring species on A. cotula''s invasive traits. These results signify that the facilitative role of AMF communities in invasion by some alien plants is contingent upon neighbour identity and the present approach provides not only a framework for further examination of the invasive plant–soil biota feedback, but also many important management implications. [Copyright &y& Elsevier]

The origin of differences in traits influencing competitive success between invasive and native wild populations of alien species is subject of debate. Herbarium-based information sources from 2005 onwards about nativity and distributional range of Phragmites australis were used to survey putative native populations of the species in Quebec, and chloroplast DNA (cpDNA) PCR-RFLP analyses identified only one native population, whereas the same analyses revealed that the Kashmir populations are invasive. We compared the native population of P. australis in Quebec (QN), ten populations invasive to Quebec (QE), and five populations invasive in Kashmir, India (KE) using morphometric traits. Using nine cpDNA microsatellite loci, we also compared nine KE populations, ten QE populations, and the QN population. Phenotypic variation was observed among and within populations. Only dry mass of flowers varied across regions. Characterization of morphotypes defined three distinct haplotypes. A bimodal distribution of stem diameter (SD), internode length (IL), leaf length (LL), and leaf width (LW) suggests that a major gene may control growth traits or occurrence of co-selection. High genetic differentiation was observed between populations (RST = 0.353) and haplotypes (RST = 0.133 to 0.418), indicating limited gene flow and probable local adaptation. Principal coordinates analysis and the neighbor-joining phylogenetic tree clearly distinguished the three haplotypes. Among-populations phenotypic difference (PST) was lower than overall RST for plant height, SD, and fresh and dry mass of flowers and seeds, whereas PST estimates for LL and LW exceeded among-populations RST, suggesting divergent selection, while local adaptation might have occurred in IL, LL, and flower masses. Genetic drift probably influenced among-populations IL differences. [ABSTRACT FROM AUTHOR]

• Our results support a positive relationship between ploidy status and species invasiveness. • Invaders are largely polyploids while endemics tend to be diploids. • However, early stage (stage II) invaders and endemics show similar levels of diploidy. • The ploidy status of invasive species can yield useful insights for biodiversity managers. Despite the recently recognized link between ploidy level and species invasiveness, disentangling ploidy variations throughout the various stages of invasion still is an open question. Therefore, our aim was to investigate the variations in the ploidy level of alien Kashmir Himalayan plant throughout different stages of invasion and to compare those variations with the ploidy levels of 112 rare endemics. Ploidy level data was derived from an extensive literature review and web-based sources. The equality of proportions test was used to assess the relationship between ploidy status and species invasiveness or rarity/endemicity. We used Pearson's product-moment correlation coefficient to test the relationship between ploidy level and diversification among some of the most widespread alien plant families. Results showed a greater preponderance of polyploidy in invasive than in rare endemic species, which were mostly diploid. Regression analysis of 309 alien plant species showed that the proportion of polyploids increases with the stage of invasion, from stage II to stage V. Our results suggest a positive relationship between ploidy status and invasiveness. We emphasize the predictive value of these variations, as our model suggests that the 32 stage II alien polyploids seem more likely to become future invaders in Kashmir Himalaya than the 46 stage II diploids. Appropriate management strategies could be put in place early enough to prevent further damage from these potentially dangerous species. [ABSTRACT FROM AUTHOR]