Response of the invasive Carpobrotus sp. to spatial and temporal heterogeneity in resource distribution

Abstract

Biological invasions are considered one of the main threats to biodiversity worldwide, altering ecosystems and affecting several ecosystem services. The invasive success of plants has been linked to strategies that increase resource use efficiency and plasticity to different environments. This work aims to compare two populations of Carpobrotus sp. growing in the same coastal dune system but located in two contrasting environments (spatial dimension: embryo dune and grey dune). It also aims to determine the effect of temporal changes in resource availability on their growth patterns (temporal dimension). The results show that regardless of the habitat of origin, Carpobrotus sp. exhibit higher growth under embryo dune conditions, which have high light and low water availability. This result suggests that radiation may be a more limiting resource for Carpobrotus sp. than water scarcity. On the other hand, it is observed that this species shows a rapid plastic response, both morphologically and physiologically, to different resource availability. Thus, Carpobrotus sp. increases the proportion biomass allocated to roots in response to water scarcity and maintains high photochemical efficiency under low light conditions. This response is interpreted as a strategy to increase efficiency in the acquisition of the most limiting resources, which would allow it to adapt efficiently to the habitat it colonizes and contribute to its invasive success. In the case of Carpobrotus sp., rather than local adaptation, high spatio-temporal plasticity is key to habitat colonization. It is crucial to understand this strategy for the protection of particularly biodiverse areas such as coastal dune systems.