This report synthesizes all aspects of the taxonomy, distribution, history of introduction and spread, ecological constrains (including preferred climate, substratum and habitats), responses to biotic and abiotic factors, biology (including phenology, vegetative and reproductive biology), economic importance and human uses, ecological impacts, legislation and management of Carpobrotus N.E.Br. (Aizoaceae), a prominent invasive plant in Europe. Carpobrotus species are mat-forming trailing succulent perennial herbs native from South Africa, introduced in Europe for ornamental and soil stabilization purposes since the beginning of the seventeenth century, now widely naturalized on coastal habitats of southern and western Europe. C. acinaciformis and C. edulis are the main species recognized outside South Africa, together with their hybrids and potential hybrid swarms. Identification conflicts both in the native and invaded areas raise doubts on the taxonomy of these taxa, but hybridization processes may boost adaptive changes in the invaded range. The release of Carpobrotus in natural environments and protected areas is prohibited in several European countries, but this taxon is not included in the list of invasive species of Union concern. Carpobrotus is a pioneer of disturbed sites and coastal areas including cliffs and sand dune systems, due to its tolerance to stress factors such as salinity, drought and excess of light. Carpobrotus invasion ultimately affects patterns of native species diversity. Moreover, it has been recognized as a major driver of soil conditions shifts and soil geochemical processes disruptions, representing a serious threat for coastal habitats. Management plans for Carpobrotus must consider its high plasticity for morphological and ecophysiological traits, which may probably explain its tolerance to a wide range of ecological conditions. Its flexible mating systems, which represent an optimal strategy to facilitate local adaptation and habitat colonization, include ability to produce apomictic seeds, self- and cross-pollination, and an intense vegetative clonality. In addition, Carpobrotus produces a large seed bank with a moderate short-term persistence, and fruits are effectively dispersed by mammals. The most efficient control methods are physical removal and herbicide application on leaves, whereas integration of biological control with other conventional management methods are likely to be most effective. A long-term monitoring of control actions and restoration of soil conditions are needed to prevent recovering from clonal parts, seed bank or mammal faeces as well as potential new invasions by other opportunistic species.

Why some species become invasive while others do not is a central research request in biological invasions. Clonality has been suggested as an attribute that could contribute to plant invasiveness. Division of labour is an important advantage of clonal growth, and it seems reasonable to anticipate that clonal plants may intensify this clonal attribute in an invaded range because of positive selection on beneficial traits. To test this hypothesis, we collected clones of Carpobrotus edulis from native and invasive populations, grew pairs of connected and severed ramets in a common garden and under negative spatial covariance of nutrients and light to induce division of labour, and measured biomass allocation ratios, final biomass and photochemical efficiency. Our results showed that both clones from the native and invaded range develop a division of labour at morphological and physiological level. However, the benefit from the division of labour was significantly higher in apical ramets from the invaded range than in ramets from the native area. This is a novel and outstanding result because it provides the first evidence that the benefit of a key clonal trait such as division of labour may have been subjected to evolutionary adaptation in the invaded range. The division of labour can therefore be considered an important trait in the invasiveness of C. edulis. An appropriate assessment of the influence of clonal traits in plant invasions seems key for understanding the underlying mechanisms behind biological invasions of new environments.

Premise: Biological invasions and climate change are major threats to biodiversity. It is therefore important to anticipate how the climate changes projected for Southern Europe would affect the ecophysiological performance of the invasive South African plant, Carpobrotus edulis (ice plant or sour fig), and its capacity to undergo rapid adaptive evolution.Methods: We manipulated the climate conditions in a field plot located on the island of Sálvora (northwest of the Iberian Peninsula) to establish a full factorial experiment with C. edulis plants transplanted from four native (southern African) and four invasive (northwestern Iberian Peninsula) populations. Throughout 14 months we measured growth and functional traits of this species under two temperatures (control vs. increased), and two rainfall levels (control vs. reduced).Results: Temperature increased photochemical efficiency and relative growth rate of C. edulis. Rainfall modulated some of the effects of temperature on C and N isotopic composition, and pigment contents. Invasive populations showed lower root mass allocation and higher survival rates, as well as increased water use efficiency, lipid peroxidation, chlorophyll, and xanthophyll cycle pigment contents than native populations.Conclusions: The increased growth and physiological performances observed under our experimental conditions suggest that the expected climate changes would further promote the invasion of C. edulis. Differences between native and invasive genotypes in survival and functional traits revealed that populations have diverged during the process of invasion, what gives support to the invasiveness hypothesis. Our findings highlight the importance of analyzing intraspecific variability in functional responses to better predict how invasive species will respond to environmental changes.

Despite the recent discoveries on how DNA methylation could help plants to adapt to changing environments, the relationship between epigenetics and climate change or invasion in new areas is still poorly known. Here, we investigated, through a field experiment, how the new expected climate scenarios for Southern Europe, i.e., increased temperature and decreased rainfall, might affect global DNA methylation in relation to phenotypic variation in individuals of clonal plant, Carpobrotus edulis, from its native (Southern African) and invaded (northwestern Iberian Peninsula) area. Our results showed that changes in temperature and rainfall induced phenotypic but not global DNA methylation differences among plants, and the climatic effects were similar for plants coming from the native or invaded areas. The individuals from the Iberian Peninsula showed higher levels of global methylation than their native counterparts from South Africa. We also observed differences between natives and invasive phenotypes in traits related to the pattern of biomass partitioning and to the strategies for water uptake and use and found an epigenetic contribution to phenotypic changes in some leaf traits, especially on the nitrogen isotopic composition. We conclude that the increased temperature and decreased rainfall projected for Southern Europe during the course of the twenty-first century may foster phenotypic changes in C. edulis, possibly endowing this species with a higher ability to successful cope the rapid environmental shifts. The epigenetic and phenotypic divergence that we observed between native and invasive plants suggests an intraspecific functional variation during the process of invasion. This result could indicate that phenotypic plasticity and global DNA methylation are related to the colonization of new habitats. Our findings reinforce the importance of epigenetic plasticity on rapid adaptation of invasive clonal plants.