Fine-scale responses of mobile invertebrates and mesopredatory fish to habitat configuration

Brendan S Lanham; Alistair G B Poore; Paul E Gribben

doi:10.1016/j.marenvres.2021.105319

Fine-scale responses of mobile invertebrates and mesopredatory fish to habitat configuration

Mar Environ Res. 2021 Jun:168:105319. doi: 10.1016/j.marenvres.2021.105319. Epub 2021 Mar 27.

Authors

Brendan S Lanham¹, Alistair G B Poore², Paul E Gribben³

Affiliations

¹ Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, NSW, Australia. Electronic address: brendan.lanham@mq.edu.au.
² Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, NSW, Australia; Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, NSW, Australia.
³ Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, NSW, Australia; Sydney Institute of Marine Science, 19 Chowder Bay Road, Mosman, NSW, 2088, Australia.

PMID: 33845258
DOI: 10.1016/j.marenvres.2021.105319

Abstract

As habitat-forming species continue to decline globally, it is important to understand how associated communities respond to habitat loss and fragmentation. Changes in the density and spatial configuration of habitat have important consequences for associated communities. However, tests of these factors are often confounded by morphological variation of habitat-formers, which can be resolved by using standardised habitat-mimics. Furthermore, few studies have incorporated the role of predators in mediating the observed effects. To test whether predators mediate the abundance of invertebrates among algal habitats of varying configuration (isolated vs patches, and positions within patches), we placed macroalgal mimics into subtidal estuarine habitats for one month to sample epifaunal communities. At the same time, we conducted underwater video surveys of fish communities to quantify fish communities and their feeding behaviour among the artificial habitats. Isolated habitats did not differ from patch habitats, however, patch edges had the highest epifaunal abundance, where fish were least commonly observed. Observed fish feeding was highest in the middle of patches and increased fish observations and feeding in habitats with reduced epifaunal communities suggest that mesopredatory fish are mediating epifauna in patches, with predation pressure altered by the spatial configuration of the habitat. This contrasts to previous studies that focus on predators that congregate outside patches and suggest that fragmentation leads to reduced invertebrate abundance at habitat edges in contrast to centres. However, this study highlights that in habitat patches housing small mesopredators that also benefit from the increased structure, the centre of the patch experiences higher predation and therefore fewer epifauna in contrast to patch edges and individual algal mimics.

Keywords: Epifauna; Fish; Macroalgae; Mimic habitat; Predation; Spatial configuration.

MeSH terms

Animals
Ecosystem*
Fishes
Invertebrates*
Plants
Predatory Behavior