Artificial reefs facilitate tropical fish at their range edge

Avery B Paxton,Brian R Silliman,Alyssa M Adler,J Christopher Taylor,Charles H Peterson,Emily A Pickering

doi:10.1038/s42003-019-0398-2

Avery B Paxton, Brian R Silliman + Show 4 more

Open Access

https://doi.org/10.1038/s42003-019-0398-2

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Abstract

Spatial planning increasingly incorporates theoretical predictions that artificial habitats assist species movement at or beyond range edges, yet evidence for this is uncommon. We conducted surveys of highly mobile fauna (fishes) on artificial habitats (reefs) on the southeastern USA continental shelf to test whether, in comparison to natural reefs, artificial reefs enhance local abundance and biomass of fishes at their poleward range margins. Here, we show that while temperate fishes were more abundant on natural reefs, tropical, and subtropical fishes exhibited higher abundances and biomasses on deep (25–35 m) artificial reefs. Further analyses reveal that this effect depended on feeding guilds because planktivorous and piscivorous but not herbivorous fishes were more abundant on artificial reefs. This is potentially due to heightened prey availability on and structural complexity of artificial reefs. Our findings demonstrate that artificial habitats can facilitate highly mobile species at range edges and suggest these habitats assist poleward species movement.

Highlights

Spatial planning increasingly incorporates theoretical predictions that artificial habitats assist species movement at or beyond range edges, yet evidence for this is uncommon
Temperate fishes occurred in higher abundance and biomass on natural, rocky reefs, whereas subtropical fishes and tropical fishes at deep depths (25–35 m) resided in higher numbers and biomass on artificial reefs
Further analysis revealed that this effect depended on feeding guilds because planktivorous and piscivorous fishes but not herbivorous fishes were more abundant on artificial reefs

Summary

Introduction

Spatial planning increasingly incorporates theoretical predictions that artificial habitats assist species movement at or beyond range edges, yet evidence for this is uncommon. Recent literature has called for strategic establishment of additional stepping stones, such as restored habitats or supplemented habitats, to facilitate species movement[15,16] This strategy, is based primarily on theory[13,15,17,18], and the effectiveness of creating habitat corridors targeting species at range edges is unknown. Artificial reefs form connectivity corridors that facilitate movement of benthic invertebrates and macroalgae, including several non-native species, among habitats[9,23,24] These human-made reefs can support a higher proportion of transient fish species than neighboring natural reefs[25]. We tested whether and how artificial reefs and natural reefs provide habitat for fishes with different climate ranges: tropical, subtropical, and temperate by conducting diving surveys of 30 warm-temperate reefs on the continental shelf of

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