Habitat and Scale Shape the Demographic Fate of the Keystone Sea Urchin Paracentrotus lividus in Mediterranean Macrophyte Communities
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Author
Tomas, Fiona
Pinna, Stefania
Farina, Simone
Roca, Guillem
Ceccherelli, Giulia
Romero, Javier
Alcoverro, Teresa
Publication date
2012-04-20ISSN
1932-6203
Abstract
Demographic processes exert different degrees of control as individuals grow, and in species that span several habitats and
spatial scales, this can influence our ability to predict their population at a particular life-history stage given the previous life
stage. In particular, when keystone species are involved, this relative coupling between demographic stages can have
significant implications for the functioning of ecosystems. We examined benthic and pelagic abundances of the sea urchin
Paracentrotus lividus in order to: 1) understand the main life-history bottlenecks by observing the degree of coupling
between demographic stages; and 2) explore the processes driving these linkages. P. lividus is the dominant invertebrate
herbivore in the Mediterranean Sea, and has been repeatedly observed to overgraze shallow beds of the seagrass Posidonia
oceanica and rocky macroalgal communities. We used a hierarchical sampling design at different spatial scales (100 s, 10 s
and ,1 km) and habitats (seagrass and rocky macroalgae) to describe the spatial patterns in the abundance of different
demographic stages (larvae, settlers, recruits and adults). Our results indicate that large-scale factors (potentially currents,
nutrients, temperature, etc.) determine larval availability and settlement in the pelagic stages of urchin life history. In rocky
macroalgal habitats, benthic processes (like predation) acting at large or medium scales drive adult abundances. In contrast,
adult numbers in seagrass meadows are most likely influenced by factors like local migration (from adjoining rocky habitats)
functioning at much smaller scales. The complexity of spatial and habitat-dependent processes shaping urchin populations
demands a multiplicity of approaches when addressing habitat conservation actions, yet such actions are currently mostly
aimed at managing predation processes and fish numbers. We argue that a more holistic ecosystem management also
needs to incorporate the landscape and habitat-quality level processes (eutrophication, fragmentation, etc.) that together
regulate the populations of this keystone herbivore.
Document Type
Article
Document version
Published version
Language
English
Subject (CDU)
574 - General ecology and biodiversity
Pages
10
Publisher
Public Library of Science
Is part of
PLoS ONE
Citation
Prado, Patricia, Fiona Tomàs, Stefania Pinna, Simone Farina, Guillem Roca, Giulia Ceccherelli, Javier Romero, and Teresa Alcoverro. 2012. “Habitat and Scale Shape the Demographic Fate of the Keystone Sea Urchin Paracentrotus Lividus in Mediterranean Macrophyte Communities.” PloS One 7 (4): e35170. doi:10.1371/journal.pone.0035170.
Grant agreement number
MICINN/Programa Nacional de Proyectos de Investigación Fundamental/CTM2010-22273-C02/ES/Evaluación experimental del efecto de los atributos del paisaje sobre interacciones funcionales entre elementos del mosaico de ecosistemas costeros/ECOMOS
Program
Aigües Marines i Continentals
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- ARTICLES CIENTÍFICS [2555]
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