Clonal integration facilitates the colonization of drought environments by plant invaders.

Yaiza Lechuga-Lago,Marta Sixto-Ruiz,Luís González,Sergio R Roiloa

doi:10.1093/aobpla/plw023

Abstract

Biological invasion represents one of the main threats for biodiversity conservation at the global scale. Identifying the mechanisms underlying the process of biological invasions is a crucial objective in the prediction of scenarios of future invasions and the mitigation of their impacts. In this sense, some plant attributes might better explain the success of invasive plant species than others. Recently, clonal growth has been identified as an attribute that could contribute to the invasiveness of plants. In this experiment, we aim to determine the effect of physiological integration (one of the most striking attributes associated with clonal growth) in the performance (at morphological and physiological levels) of the aggressive invader Carpobrotus edulis, when occupying stressful environments. To achieve this objective we performed a greenhouse experiment in which apical ramets of C. edulis were water-stressed and the connection with the basal ramets was either left intact (physiological integration is allowed) or severed (physiological integration is impeded). Our results show that clonal integration allowed apical ramets to buffer drought stress in terms of photochemical activity, and as a consequence, to increase their growth in comparison with severed apical ramets. Interestingly, this increase in biomass was mainly due to the production of aboveground structures, increasing the spread along the soil surface, and consequently having important implications for the colonization success of new environments by this aggressive invader.

Highlights

Biological invasions occur when non-indigenous species spread to areas outside their region of origin (Colautti and MacIsaac 2004; Jeschke and Strayer 2005)
We aim to address the following questions: (i) Does physiological integration increase photochemical activity and growth of C. edulis? We expect a benefit for apical ramets derived of the support received from basal ramets. (ii) If so, are the benefits more evident when apical ramets grow under water-stressed conditions? We predict that the benefit will be more noticeable for apical ramets in stressful conditions, where support could be essential to maintain photochemical activity and growth
Drought conditions often occur in sand dune systems, and our results indicate that clonal integration would contribute to the expansion of this invader in waterstressed conditions, with the consequent implications in the understanding of the invasiveness of C. edulis in sand dune systems

Summary

Introduction

Biological invasions occur when non-indigenous species spread to areas outside their region of origin (Colautti and MacIsaac 2004; Jeschke and Strayer 2005). In this new environment their descendants proliferate, spread and persist (Mack et al 2000). These invasive species have a high potential to alter the structure and function of the ecosystem (e.g. alterations of the physical, chemical and biological soil properties, nutrient cycling and plant productivity) (Levine et al 2003; Otfinowski and Kenkel 2008; Chacon et al 2009; Castro-Dıez et al 2012; Novoa et al 2014; Souza-Alonso et al 2015).

Objectives

Methods

Results

Discussion

Conclusion