Create natural rocky reef topography on intertidal artificial structures

How is the evidence assessed?
  • Effectiveness
    not assessed
  • Certainty
    not assessed
  • Harms
    not assessed

Study locations

Key messages

  • Two studies examined the effects of creating natural rocky reef topography on intertidal artificial structures on the biodiversity of those structures. One study was on an open coastline and in estuaries in the UK, and one was on an open coastline in the UK.

COMMUNITY RESPONSE (1 STUDY)

  • Overall richness/diversity (1 study): One replicated, randomized, controlled study in the UK found that creating natural rocky reef topography on intertidal artificial structures did not increase the combined macroalgae and invertebrate species richness on structure surfaces.

POPULATION RESPONSE (1 STUDY)

  • Invertebrate abundance (1 study): One replicated, randomized, controlled study in the UK found that creating natural rocky reef topography on intertidal artificial structures had mixed effects on barnacle and mobile invertebrate abundances on structure surfaces, depending on the site.

BEHAVIOUR (1 STUDY)

  • Use (1 study): One study in the UK reported that natural topography created on intertidal artificial structures was colonized by macroalgae and limpets, and that limpets used shaded grooves and water-retaining depressions created by the topography.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated, randomized, controlled study in 2016–2017 on three intertidal seawalls in the Clyde and Forth estuaries and on open coastline in the English Channel, UK (MacArthur et al. 2019) found that creating natural rocky reef topography on the seawalls did not increase the macroalgae and invertebrate species richness on seawall surfaces, but increased invertebrate abundances at one of three sites. After 18 months, macroalgae and mobile invertebrate species richness was similar on settlement plates with and without natural rocky reef topography (both 1 species/plate). Barnacle (Cirripedia) and mobile invertebrate abundances were higher on plates with topography than without at one site (barnacles: 72 vs 34% cover; mobiles: 3 vs 1 individuals/plate), but were statistically similar at two sites (barnacles: 48–93 vs 22–83%; mobiles: 1 vs 2–3/plate). Concrete settlement plates (150 × 150 mm) were made with and without natural rocky reef topography moulded from digital scans of a natural boulder surface. Eight plates with topography and eight without were randomly arranged at upper-midshore on each of three vertical concrete seawalls in April–May 2016. Macroalgae and invertebrates on plates were counted from photographs over 18 months.

    Study and other actions tested
  2. A study in 2019 on two intertidal breakwaters on open coastline in the Irish Sea, UK (Evans et al. 2021) reported that natural rocky reef topography created on the breakwaters supported macroalgae (Ulva spp.) and limpets (Patella spp.). Over four months, green macroalgae and adult and juvenile limpets were recorded on settlement plates with natural rocky reef topography. Limpets were seen using shaded grooves and water-retaining depressions created by the natural topography. Concrete settlement plates (250 × 250 mm) were made with natural rocky reef topography moulded from digital scans of natural reef surfaces. Natural surfaces were selected based on the biodiversity they supported and measured features of the underlying topography. They were designed to target high species richness, rare species, or species that were common on natural reefs but not on artificial structures. Plates with natural topography were attached on horizontal surfaces of two granite boulder breakwaters in August 2019 (A. Evans, pers. comms.). Macroalgae and invertebrates on plates were counted during low tide over four months.

    Study and other actions tested
Please cite as:

Evans, A.J., Moore, P.J., Firth, L.B., Smith, R.K., and Sutherland, W.J. (2021) Enhancing the Biodiversity of Marine Artificial Structures: Global Evidence for the Effects of Interventions. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Biodiversity of Marine Artificial Structures

This Action forms part of the Action Synopsis:

Biodiversity of Marine Artificial Structures
Biodiversity of Marine Artificial Structures

Biodiversity of Marine Artificial Structures - Published 2021

Enhancing biodiversity of marine artificial structures synopsis

What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 18

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust