Create long flexible habitats (>50 mm) on intertidal artificial structures

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

Study locations

Key messages

  • One study examined the effects of creating long flexible habitats on intertidal artificial structures on the biodiversity of those structures. The study was in a port in the Netherlands.


  • Overall community composition (1 study): One replicated, controlled study in the Netherlands reported that creating long flexible habitats on intertidal artificial structures altered the combined macroalgae and non-mobile invertebrate community composition on structure surfaces. The flexible habitats themselves supported macroalgae, mobile and non-mobile invertebrates that were absent from structure surfaces without flexible habitats.




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. One replicated, controlled study in 2009 on five intertidal jetty pilings in the Port of Rotterdam, the Netherlands (Paalvast et al. 2012) reported that creating long flexible habitats (‘hulas’) on pilings altered the macroalgae and non-mobile invertebrate community composition on piling surfaces, and that hulas were colonized by macroalgae and invertebrates, but data were not statistically tested. After eight months, hula ropes supported mussels (Mytilus edulis: 5% cover), barnacles (Amphibalanus improvisus: 1%), red macroalgae (Ceramium rubrum: 0.2%) and amphipods (Amphipoda: 11–100 individuals/rope), which were all absent from piling surfaces without flexible habitats. Average biomass on ropes was 1 g/cm. Piling surfaces under hulas supported mostly barnacles (50% cover), while pilings without flexible habitats supported mostly green macroalgae (50% cover). Long flexible habitats were created by attaching polyamide rope skirts (‘hulas’) around pilings in March 2009. One hula with 167 ropes (diameter: 6 mm; length: 550 mm; density: 167/m) was attached at lowshore around each of five wooden pilings, cleared of organisms. Hulas were compared with intertidal surfaces (200 × 200 mm) on five pilings without flexible habitats, cleared of organisms. Macroalgae and invertebrates on hula ropes and piling surfaces were counted and biomass (wet weight) measured in the laboratory over eight 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

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