Exploring coexistence mechanisms in a three-species assemblage

Interactions among species are essential in shaping ecological communities, although it is not always clear under what conditions they can persist when the number of species involved is higher than two. Here we describe a three-species assemblage involving the seagrass Cymodocea nodosa, the pen shel...

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Bibliographic Details
Authors: Sanmartí, Neus, Ontoria Gómez, Yaiza, Martínez Ricart, Aurora, Arthur, Rohan, Alcoverro, Teresa, Pérez Vallmitjana, Marta, Romero, Javier (Romero Martinengo)
Format: article
Status:Published version
Publication Date:2022
Country:España
Institution:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repository:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/216536
Online Access:https://hdl.handle.net/2445/216536
Access Level:Open access
Keyword:Bivalves
Fanerògames
Eriçons de mar
Phanerogams
Sea urchins
Description
Summary:Interactions among species are essential in shaping ecological communities, although it is not always clear under what conditions they can persist when the number of species involved is higher than two. Here we describe a three-species assemblage involving the seagrass Cymodocea nodosa, the pen shell Pinna nobilis and the herbivore sea urchin Paracentrotus lividus, and we explore the mechanisms allowing its persistence through field observations and manipulative experiments. The abundance of pen shells was higher in seagrass beds than in bare sand, suggesting a recruitment facilitation. The presence of sea urchins, almost exclusively attached or around pen shells, indicated habitat facilitation for sea urchins, which overgrazed the meadow around the pen shells forming seagrass-free halos. Our results suggest that this system persists thanks to: (i) the behavioral reluctance of sea urchins to move far from pen shells, making their impact on seagrass strictly local, (ii) the sparse distribution of pen shells and (iii) the plant's resistance mechanisms to herbivory. Unpacking these mechanisms allows a better understanding of how ecological communities are assembled.