Modified habitats influence kelp epibiota via direct and indirect effects

Published source details Marzinelli E.M., Underwood A.J. & Coleman R.A. (2011) Modified habitats influence kelp epibiota via direct and indirect effects. PLoS ONE, 6, e21936.
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This study is summarised as evidence for the following.

	Action	Category
	Transplant or seed organisms onto subtidal artificial structures Action Link

Transplant or seed organisms onto subtidal artificial structures

A replicated, randomized, controlled and site comparison study in 2006–2007 on 20 subtidal jetty pilings in Sydney Harbour estuary, Australia (Marzinelli et al. 2011) reported that 100% of sea urchins Holopneustes purpurascens transplanted onto pilings survived, and found that transplanting urchins reduced the non-native sea mat cover (mostly Membranipora membranacea) on kelp Ecklonia cava growing on the pilings. After one month, all transplanted sea urchins remained on pilings. Non-native sea mat cover on kelp was lower on pilings with transplanted urchins (0–19% cover) than on pilings without (29–89%), and similar to kelp on natural reefs in one of two trials (pilings with urchins: 0–6%; natural reefs: 1%), but higher on pilings in the second trial (pilings with urchins: 17–19%; natural reefs: 2–3%). Sea urchins (>50 mm diameter) were collected from natural reefs and transplanted onto kelp growing on wooden jetty pilings (1.5 × 1.5 m surfaces) at 0–3 m depth, with five urchins/piling. Five pilings with urchins and five without were randomly arranged in each of two sites on a jetty in November 2006. Transplanted urchins were counted and non-native sea mat cover on kelp blades was measured from photographs after one month. Sea mat cover was also measured on kelp on nearby natural reefs. The experiment was repeated in April 2007.

(Summarised by: Ally Evans)