The time lag between introduction and escape from cultivation of alien woody plant species decreases with polyploidization

Abstract

Abstract. The time between introduction of an alien species and escape from cultivation shows considerable variation among species. One hypothesis to explain this variation of the time lag invokes the evolution of genotypes adapted to the conditions of the new environment. Here, we analyse the variation in time lags among 53 alien woody plant species in Germany. Accounting for the effects of time since introduction, growth form (trees versus shrubs), biogeography and taxonomic isolation (presence or absence of a native congener in the adventive area) we found that the time lag decreases with increasing polyploidization. By contrast, the haploid chromosome number was not significantly related to the time lag. These results provide evidence for the hypothesis that recent genome duplication events are important for a fast escape from cultivation of an alien woody plant species. We suggest that a large number of duplicated chromosomes increase the partitioning of the genome and hence the average rate of recombination between loci facilitating the formation of adaptive genotypes.

Reproductive Ecology of the Invasive Alien Shrub Pyracantha angustifolia in the Grassland Biome, South Africa

“…It is now widespread in the temperate grasslands of the Eastern Cape, Free State, KwaZulu–Natal, and Mpumalanga provinces, as well as in the adjacent countries of Lesotho, Eswatini, and Zimbabwe [ 19 , 20 ]. Pyracantha angustifolia has also naturalised in Argentina [ 21 ]; Australia [ 22 ]; Brazil [ 23 ]; Canada, Columbia, England, and France [ 24 ]; the French Polynesian Islands and Hawaii [ 25 ]; Italy, Japan, Mexico, New Zealand, Portugal, and Russia [ 25 ]; Spain, and the United States of America [ 26 , 27 ]; and Germany [ 28 ]. In southern Africa, by transforming an open habitat into a “ Pyracantha savannah” or “thicket”, P. angustifolia competes with and displaces native plant species, erodes habitat suitability for endemic grassland fauna (many being of high conservation concern), provides a nursery habitat for additional invasive species, alters fire regimes, reduces rangeland capacity and dependent livelihoods, and reduces eco-tourism revenue when invading places of scenic beauty [ 13 , 29 ].…”