Create crevice habitats (>50 mm) on intertidal artificial structures

Overall effectiveness category No evidence found (no assessment)
Number of studies: 0
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Effectiveness

not assessed
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not assessed
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Background information and definitions

Definition: ‘Crevice habitats’ are depressions with a length to width ratio >3:1 and depth >50 mm (modified “Crevices” from Strain et al. 2018).

Crevice habitats provide organisms refuge from desiccation and temperature fluctuations during low tide in intertidal rocky habitats (Williams & Morritt 1995). They also provide shelter from predation or grazing (Menge & Lubchenco 1981) and some species preferentially settle into them (Chabot & Bourget 1988). The size and density of crevices is likely to affect the size, abundance and variety of organisms that can use them. Small crevices can provide refuge for small-bodied organisms but may exclude larger organisms, limit their growth and get rapidly filled-up (Firth et al. 2020). Large crevices can be used by larger-bodied organisms but may not provide sufficient refuge from predators for smaller organisms. By default, crevices contain shaded surfaces, which can be associated with the presence of non-native species (Dafforn 2017).

Crevices sometimes form on artificial structures through erosion. However, these are often filled or repaired during maintenance works (Moreira et al. 2007) and are absent from many structures (Aguilera et al. 2014). Crevice habitats can be created on intertidal artificial structures by adding or removing material, either during construction or retrospectively.

^{Aguilera M.A., Broitman B.R. & Thiel M. (2014) Spatial variability in community composition on a granite breakwater versus natural rocky shores: lack of microhabitats suppresses intertidal biodiversity. Marine Pollution Bulletin, 87, 257–268.}

^{Chabot R. & Bourget E. (1988) Influence of substratum heterogeneity and settled barnacle density on the settlement of cypris larvae. Marine Biology, 97, 45–56.}

^{Dafforn K.A. (2017) Eco-engineering and management strategies for marine infrastructures to reduce establishment and dispersal of non-indigenous species. Management of Biological Invasions, 8, 153–161.}

^{Firth L.B., Airoldi L., Bulleri F., Challinor S., Chee S.-Y., Evans A.J., Hanley M.E., Knights A.M., O’Shaughnessy K., Thompson R.C. & Hawkins S.J. (2020) Greening of grey infrastructure should not be used as a Trojan horse to facilitate coastal development. Journal of Applied Ecology, 57, 1762–1768.}

^{Menge B.A. & Lubchenco J. (1981) Community organization in temperate and tropical rocky intertidal habitats: prey refuges in relation to consumer pressure gradients. Ecological Monographs, 51, 429–450.}

^{Moreira J., Chapman M.G. & Underwood A.J. (2007) Maintenance of chitons on seawalls using crevices on sandstone blocks as habitat in Sydney Harbour, Australia. Journal of Experimental Marine Biology and Ecology, 347, 134–143.}

^{Strain E.M.A., Olabarria C., Mayer-Pinto M., Cumbo V., Morris R.L., Bugnot A.B., Dafforn K.A., Heery E., Firth L.B., Brooks P.R. & Bishop M.J. (2018) Eco-engineering urban infrastructure for marine and coastal biodiversity: which interventions have the greatest ecological benefit? Journal of Applied Ecology, 55, 426–441.}

^{Williams G.A. & Morritt D. (1995) Habitat partitioning and thermal tolerance in a tropical limpet, Cellana grata. Marine Ecology Progress Series, 124, 89–103.}

Key messages

We found no studies that evaluated the effects of creating crevice habitats on intertidal artificial structures on the biodiversity of those structures.

This means we did not find any studies that directly evaluated this intervention during our literature searches. Therefore, we have no evidence to indicate whether or not the intervention has any desirable or harmful effects.

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.

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?

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This Action forms part of the Action Synopsis:

Biodiversity of Marine Artificial Structures

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