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Long-term trends in invertebrate-habitat relationships under protected and fished conditions

Alexander, Timothy ; Johnson, Craig ; Haddon, Malcolm ; Barrett, Neville ; Edgar, Graham

In: Marine Biology, 2014, vol. 161, no. 8, p. 1799-1808

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    Titre
    • Long-term trends in invertebrate-habitat relationships under protected and fished conditions
    Auteur
    • Alexander, Timothy. Institute of Marine and Antarctic Studies, University of Tasmania, Private Bay 49, 7001, Tasmania, Australia
    • Johnson, Craig. Institute of Marine and Antarctic Studies, University of Tasmania, Private Bay 49, 7001, Tasmania, Australia
    • Haddon, Malcolm. CSIRO Marine and Atmospheric Research, Castray Esplanade, 7000, Hobart Tasmania, Australia
    • Barrett, Neville. Institute of Marine and Antarctic Studies, University of Tasmania, Private Bay 49, 7001, Tasmania, Australia
    • Edgar, Graham. Institute of Marine and Antarctic Studies, University of Tasmania, Private Bay 49, 7001, Tasmania, Australia
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Marine Biology, 2014, vol. 161, no. 8, p. 1799-1808. Springer Berlin Heidelberg
    Autre version électronique
    Classification
    • Sciences de la terre
    Identifiant OAI-PMH
    • oai:doc.rero.ch:325816
    Summary
    Few studies examine the long-term effects of changing predator size and abundance on the habitat associations of resident organisms despite that this knowledge is critical to understand the ecosystem effects of fishing. Marine reserves offer the opportunity to determine ecosystem-level effects of manipulated predator densities, while parallel monitoring of adjacent fished areas allows separating these effects from regional-scale change. Relationships between two measures of benthic habitat structure (reef architecture and topographic complexity) and key invertebrate species were followed over 17years at fished and protected subtidal rocky reefs associated with two southern Australian marine reserves. Two commercially harvested species, the southern rock lobster (Jasus edwardsii) and blacklip abalone (Haliotis rubra) were initially weakly associated with habitat structure across all fished and protected sites. The strength of association with habitat for both species increased markedly at protected sites 2years after marine reserve declaration, and then gradually weakened over subsequent years. The increasing size of rock lobster within reserves apparently reduced their dependency on reef shelters as refuges from predation. Rising predation by fish and rock lobster in the reserves corresponded with weakening invertebrate-habitat relationships for H. rubra and sea urchins (Heliocidaris erythrogramma). These results emphasise that animal-habitat relationships are not necessarily stable through time and highlight the value of marine reserves as reference sites. Our work shows that fishery closures to enhance populations of commercially important and keystone species should be in areas with a range of habitat features to accommodate shifting ecological requirements with ontogenesis.