The interspecific abundance–occupancy relationship in rocky intertidal communities

ABSTRACT

A commonly assumed pattern in species assemblages is the abundance–occupancy relationship (AOR), which refers to a relationship between the mean local abundance of each species and the proportion of local sites that each species occupies. The AOR concept is relevant because it allows researchers to make inferences or predictions between species abundance and occupancy, which are key variables in ecology. Although the AOR is thought to be ubiquitous, it has not been found for every system where it has been tested. To date, the studies that have evaluated its generality were largely done in terrestrial systems. Therefore, there is a need to evaluate its occurrence in aquatic systems. This study tests whether the AOR occurs in rocky intertidal systems. Using data for algae and invertebrates from Atlantic Canada, we show that the negative binomial model properly describes the relationship between abundance and occupancy in rocky intertidal communities. Moreover, we found the AOR to hold for two hydrodynamically contrasting habitat types. Overall, these findings expand the applicability of the AOR to marine benthic systems. The raw data are included as part of this article and should be valuable for future syntheses on the AOR, as such studies will benefit from using datasets spanning terrestrial and aquatic systems. In this sense, our abundance data are particularly relevant because they describe density of organisms, which is a condition for AOR modelling that intertidal ecological studies typically do not follow entirely, as the abundance of sessile species is often measured as percent cover.

KEYWORDS:

• Benthic
• intertidal
• invertebrate
• seaweed
• species composition
• wave exposure

Acknowledgements

We are grateful to an anonymous reviewer for helpful comments on an earlier version of this manuscript.

Data availability

The dataset used for this article is freely available from the figshare online repository: https://doi.org/10.6084/m9.figshare.19579003.v1.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by a Discovery grant (# 311624) from the Natural Sciences and Engineering Research Council of Canada (NSERC), by a grant (# 210283) from the Canada Research Chairs program (CRC), and by a Leaders Opportunity grant (# 202034) from the Canada Foundation for Innovation (CFI) awarded to RAS.