Time-dependent effects of orientation, heterogeneity and composition determines benthic biological community recruitment patterns on subtidal artificial structures

Published source details Hanlon N., Firth L.B. & Knights A.M. (2018) Time-dependent effects of orientation, heterogeneity and composition determines benthic biological community recruitment patterns on subtidal artificial structures. Ecological Engineering, 112, 219-228.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	*Create grooves and* small protrusions, ridges or ledges (1–50 mm) on subtidal artificial structures** Action Link
	Use environmentally-sensitive material on subtidal artificial structures Action Link

Create grooves and small protrusions, ridges or ledges (1–50 mm) on subtidal artificial structures

A replicated, randomized, controlled study in 2016 on pontoons in a marina in the Fal estuary, UK (Hanlon et al. 2018) found that upward-facing settlement plates with groove habitats and small protrusions supported different macroalgae and invertebrate community composition, with similar species diversity but higher species richness and abundances, than upward-facing plates without grooves or protrusions, but that there were no significant differences on downward-facing plates. After six months, upward-facing plates with grooves and protrusions supported different macroalgae and invertebrate community composition (data reported as statistical model results) with similar species diversity (data not reported) but higher species richness (20 species/plate, reported from Figure 4) and macroalgae and non-mobile invertebrate live cover (29% cover), compared with plates without grooves and protrusions (15 species/plate, 13% cover). On downward-facing plates, there were no significant differences between plates with and without grooves and protrusions (both 25 species/plate; 92 vs 86% cover). Settlement plates (150 × 150 mm) were moulded with a regular grid of six groove habitats (length: 150 mm; width/depth: 10 mm) between 15 rectangular small protrusions (length: ~44 mm; width: ~22 mm; height: 10 mm) on one surface, but flat on the other. Plates were either standard-concrete or oyster-shell-concrete. Forty plates were suspended horizontally, randomly arranged, beneath floating pontoons at 2–3 m depth in April 2016. Ten of each material had grooves and protrusions facing up, while 10 of each faced down. Macroalgae and invertebrates on upward- and downward-facing surfaces were counted in the laboratory over six months.

(Summarised by: Ally Evans)
Use environmentally-sensitive material on subtidal artificial structures

A replicated, randomized, controlled study in 2016 in a marina in the Fal estuary, UK (Hanlon et al. 2018) found that shell-concrete settlement plates supported different macroalgae and invertebrate community composition, with higher bivalve abundance but similar species diversity and live cover to standard-concrete plates, while species richness varied depending on the surface orientation. After six months, shell-concrete settlement plates supported different macroalgae and invertebrate community composition (data reported as statistical model results) with similar species diversity and live cover (data not reported) to standard-concrete plates. Species richness comparisons varied depending on the surface orientation (data not reported). Bivalve abundance (Anomia ephippium, Hiatella arctica, Musculus costulatas) was 38% higher on shell-concrete than standard-concrete plates. Settlement plates (150 × 150 mm) were moulded from oyster-shell-concrete and standard-concrete. Plates had grooves and small protrusions on one surface, but were flat on the other. Forty plates were suspended horizontally, randomly arranged, beneath floating pontoons at 2–3 m depth in April 2016. Ten of each material had grooves/protrusions facing up, while 10 of each faced down. Macroalgae and invertebrates on upward- and downward-facing surfaces were counted in the laboratory over six months.

(Summarised by: Ally Evans)