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

Alexander, Timothy; Johnson, Craig R.; Haddon, Malcolm; Barrett, Neville S.; Edgar, Graham J. (2014). Long-term trends in invertebrate–habitat relationships under protected and fished conditions. Marine Biology, 161(8), pp. 1799-1808. Springer 10.1007/s00227-014-2462-2

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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 17 years 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 2 years 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.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE)
08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Aquatic Ecology

UniBE Contributor:

Alexander, Timothy

Subjects:

500 Science > 570 Life sciences; biology

ISSN:

0025-3162

Publisher:

Springer

Language:

English

Submitter:

Marcel Häsler

Date Deposited:

20 Jul 2015 15:29

Last Modified:

08 Sep 2015 09:57

Publisher DOI:

10.1007/s00227-014-2462-2

BORIS DOI:

10.7892/boris.70354

URI:

https://boris.unibe.ch/id/eprint/70354

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