Plant-soil feedback as a mechanism of invasion by Carpobrotus edulis

Abstract

Invasive plant species have been suggested to change the composition of the soil community in a way that results in a positive feedback for them and a negative feedback for the native plant community. Carpobrotus edulis, a species native to South Africa, is one of the most aggressive exotic species in Mediterranean Europe. Although several aspects of its invasion biology have been studied, the occurrence of plant-soil feedback has been scarcely investigated. We first checked for the existence of biotic resistance in soils from two invaded sites of Mediterranean Europe and one site in the native area. Secondly, we evaluated the effects of soil conditioning on the germination and plant growth of C. edulis and two key species of native dunes. Finally, we tested the effects of short-and long-term soil conditioning on the performance and reproductive effort of C. edulis. Our results show that at first there is a natural resistance to invasion by the soil biota. Later, biotic resistance in invaded soil is suppressed by the establishment of a soil community that enhances the growth of C. edulis and that negatively influences the growth and survival of the native plants. Long-term soil conditioning in the field resulted in shifts in the balance between vegetative growth and sexual reproduction. Long-term invasion was also reflected in high levels of endophyte colonization by chytrids in roots, although the physiological consequences of this colonization remain unknown. The results obtained illustrate a mechanism that explains how C. edulis breaks the initial biotic resistance of newly-invaded landscapes. Finally, this study highlights the importance of studying plant-soil interactions on different members of the plant community and temporal stages in order to fully understand invasion.

The impact of Carpobrotus cfr. acinaciformis (L.) L. Bolus on soil nutrients, microbial communities structure and native plant communities in Mediterranean ecosystems

“…invasive success (D'Antonio 1990b(D'Antonio , 1993D'Antonio et al 1993;Novoa et al 2012) and to assessing the ecological consequences associated with their invasion on floristic richness and diversity (Carta et al 2004;Vilà et al 2006;Andreu et al 2010;Novoa et al 2013;Chenot et al 2014;Fried et al 2014), on soil properties (Vilà et al 2006;Conser and Connor 2009;de la Peña et al 2010;Santoro et al 2011;Novoa et al 2013 or on both (Vilà et al 2006;Novoa et al 2013). In all previous references, Carpobrotus spp.…”

Changes in the Abundance of Grassland Species in Monocultures versus Mixtures and Their Relation to Biodiversity Effects

“…Such positive plant–soil feedbacks have mainly been studied in the context of plant invasions (see e.g. [30], [31], [32]). …”

Effects of Soil Characteristics, Allelopathy and Frugivory on Establishment of the Invasive Plant Carpobrotus edulis and a Co-Occuring Native, Malcolmia littorea

“…It is among the most intensively studied invasive plants globally [24], and those the impacts of which are often addressed [25]. When C. edulis invades coastal habitats [26], it modifies certain soil parameters [27], [28], [29], [30], which can have a great impact on community composition, diversity and succession [31], [32]. Some of these changes, such as in moisture content, pH, and salinity, influence the germination and early growth of native plants (Novoa and González, unpublished) as well as its own performance [33], and persist following the removal of the invader [34], [35].Thus, an improved understanding of the interactions between those factors is crucial for a better mitigation of the impacts caused by C. edulis in the Mediterranean ecosystems.…”