The use of glyphosate for Carpobrotus eradication in sand dune ecosystems: evaluation of the potential effects on the reintroduction of native plants

Abstract

Glyphosate application avoids some problems associated with manually controlling Carpobrotus. However, before it can be extended, we must understand whether residual glyphosate affects the restoration of natural vegetation by sowing or planting. Thus, we sprayed glyphosate on plots with 100% Carpobrotus coverage at 10 times the maximum recommended dose (4 g/m²) and directly on sand at 0.3 and 4 g/m². Sand, sifted sand without Carpobrotus litter and sand with Carpobrotus litter were subsequently collected 15, 30, and 60 days after applications, and were used as substrates to evaluate seedling emergence of four native dune species sown in trays. We also assessed the development of two species when grown in pots. Seedling emergence of M. marina, L. creticus and O. ramosissima was not affected in sand without Carpobrotus litter; A. arenaria emergence was reduced by 35%. Seedling emergence of four dune species was inhibited when glyphosate had been directly sprayed on sand. Effect of dose and time after spraying was observed. The presence of Carpobrotus litter reduced the emergence of L. creticus, O. ramosissima and A. arenaria, and inhibition seemed be caused by the allelopathic properties of the Carpobrotus litter. No significant effects of glyphosate spraying were observed in growth tests.

Keywords:

• Carpobrotus
• chemical control
• dune restoration
• glyphosate
• native plant reintroduction

Acknowledgements

The authors would like to thank of the Valencian Region Government environmental officers, Gabriel Ballester and Vicente Deltoro for their logistic support, as well as the seed bank at the Centre for Forest Research and Experimentation (CIEF, Generalitat Valenciana) for supplying the native species seeds. Finally, we thank Dr. Eduardo Rojas and Dr. Rafael Sirera for their critical review of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was made possible through significant support from the Conselleria de Territori i Habitatge, Generalitat Valenciana (grant Number T621700) and from the Conselleria d’Educació, Generalitat Valenciana (project GVPRE/2008/134).

Funding

This study was made possible through significant support from the Conselleria de Territori i Habitatge, Generalitat Valenciana (grant Number T621700) and from the Conselleria d’Educació, Generalitat Valenciana (project GVPRE/2008/134).