Canopy-forming algae play a key role in temperate coastal ecosystems sustaining complex habitats that provide food and refuge for rich associated biotic communities. These macroalgae are in decline in many coastal areas, where overgrazing by herbivores can lead to the loss of these highly structured and diverse habitats toward less complex sea urchin barren grounds. Once established, low productive barren grounds are considered stable states maintained by several positive feedback mechanisms that prevent the recovery of marine forests. To revert this global decline, restoration efforts and measures are being encouraged by EU regulations and local actions. Here, we tested the success of active revegetation techniques as a tool to promote functional and productive Treptacantha elegans forests in sea urchin barren grounds under different restoration strategies (active, and combined active with passive strategies). Active revegetation was performed in 6 barren grounds, 3 located inside a Mediterranean No-Take marine reserve (active and passive strategy) and 3 outside (active strategy alone), following a three-step protocol: (1) sea urchin population eradication, (2) seeding with Treptacantha elegans, and (3) enhancement of T. elegans recruitment. Revegetation success was assessed 1 year later in the six barren grounds, but was only achieved after combining active with passive restoration strategies. Our results encourage revegetation of barren grounds to shift from less productive habitats to complex T. elegans forests, highlight the potential of the combined passive and active restoration strategies, as well as the important role of marine reserves not only in conservation but also in ecological restoration.
|Original language||English (US)|
|Number of pages||13|
|State||Published - Jan 18 2020|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This study would not have been possible without the field support of many colleagues, including Daniel Gómez-Gras, Eneko Aspillaga, Pol Capdevila, Quim Garrabou, Ignasi Montero-Serra, Júlia Ortega, Mikel Zabala, Nur Arafeh-Dalmau, and Tulasi Prasanna. We would like to thank the administration of the Montgrí, Illes Medes, and Baix Ter Natural Park for their support on marine restoration activities and the legal permissions for the activities carried out for this study. This work was supported by the long-term monitoring programme of the Natural Park of Cap de Creus and the Natural Park of the Montgrí, the Medes Islands and the Baix Ter protected areas (public agreement PTOP- 2017-130, Departament de Territori i Sostenibilitat of the Generalitat de Catalunya) and by the European Union's Horizon 2020 research and innovation programme under grant agreement No 689518 (MERCES). This output reflects only the authors' view, and the European Union cannot be held responsible for any use of the information contained herein that may be made. The authors are part of the Marine Conservation research group (2017 SGR 1521) funded by Generalitat de Catalunya. The authors state that they have no conflict of interest related to this work.