Role of predators in the recruitment of invertebrates in a rocky subtidal community in the southwest Bay of Fundy, NB

ABSTRACT

Predation is potentially an influential source of early post-settlement mortality of benthic marine invertebrates, but previous studies demonstrate conflicting results. We investigated the effect of large predators on developing subtidal invertebrate communities in cobble-filled collectors in the southwest Bay of Fundy, Canada. Two predation treatments (exclusion of predators ≥ 7 mm body width or full access for predators < 50 mm) were used to test the effect of large predators, and a partial-cage control tested for caging artefacts. Despite a reduction in the abundance and biomass of large predators, multivariate analyses indicated no effect of predator exclusion on the composition of the prey and micropredator communities. Results indicated that the largest differences were between the predator-access treatment and the other two treatments, which was potentially influenced by the caging material. There were significant but weak positive correlations between the micropredator and the other two communities. Previous studies indicate that at low predation intensity, as seemed to be the case here, other factors may play a stronger role in controlling recruit abundance. Predation control probably varies spatially and temporally, and the influence of large predators was not likely the driving force for early post-settlement mortality in the invertebrate communities measured in this study.

KEYWORDS:

• Early post-settlement mortality
• predation
• benthic marine invertebrates
• subtidal

Acknowledgements

We thank Marie-Josee Maltais for organizing field work and providing taxonomic assistance. Lauren Ellis, Gudjon Sigurdsson, Brent Wilson, Greg Wittig, Neill Davis, Lacey Haddon, Marie-Josee Abgrall, Connie Browne, Bryan Morse, Ellen Boyd, Becky McBriarty, Jeff Clements, Kristin Legault, Kristin Dinning, Brady Quinn, Samantha Thurlow, Feng Tang and the crew of Fundy Spray assisted in the field. We thank Rémy Rochette, Myriam Barbeau, Gerhard Pohle and Lisa Best for providing valuable feedback on earlier versions of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

Betsy L. O’Malley http://orcid.org/0000-0002-8015-2578

Heather L. Hunt http://orcid.org/0000-0002-5500-5015

Additional information

Funding

This work was supported by the Natural Sciences and Engineering Research Council of Canada under a Strategic Project Grant [number 364903-08] to Rémy Rochette and Heather Hunt.