Restore or create kelp forests

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

60%
Certainty

15%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Kelp forests are unique habitats found in mostly cold, nutrient-rich waters. Large kelps such as Macrocystis spp. (the ‘giant kelps’) can grow to 45 m or more, creating ‘underwater forests’ that provide complex habitats and allow extremely productive ecosystems to flourish. However, they are vulnerable to pollution and ecosystem perturbations caused by, for example, the loss of keystone species such as sea otters Enhydra lutris (Jackson et al. 2001).

Jackson, J.B.C., Kirby, M.X., Berger, W.H., Bjorndal, K.A., Botsford, L.W., Bourque, B.J., Bradbury, R.H., Cooke, R., Erlandson, J., Estes, J.A. & others. (2001) Historical overfishing and the recent collapse of coastal ecosystems. Science, 293, 629–637.

Study locations

Key messages

A before-and-study in the USA found that the densities of five of the nine bird species analysed increased following kelp forest restoration.

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

A before-and-after study between 1969-1973 and 1984-1986 on a rocky shoreline in southern California, USA (Bradley & Bradley 1993), found that shorebirds were significantly more numerous after kelp Macrocystis pyrifera forest restoration. Among nine species of shorebird analysed, the density of five (spotted sandpiper Actitus macularia, wandering tattler Heteroscelus incanus, whimbrel Numenius phaeopus, black turnstone Arenaria melanocephala and ruddy turnstone Arenaria interpres) increased. Territorial species (spotted sandpiper, wandering tattler and whimbrel) were twice as abundant in the second census. Species that do not forage in algal windthrow, such as the black-bellied plover Pluvialis squatarola, remained stable over the two census periods. Complete counts of all shorebirds encountered along a 4 km census route were recorded year-round over the years of the two censuses.
Study and other actions tested
Referenced paper
Bradley R.A. & Bradley D.W. (1993) Wintering shorebirds increase after kelp (Macrocystis) recovery. The Condor, 95, 372-376.

Please cite as:

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J. & Sutherland, W.J. (2020) Bird Conservation. Pages 137-281 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Bird Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Restore or create forests Action Link	Beneficial	16	Synopsis Link
Restore or create kelp forests Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link
Revegetate gravel pits Action Link	No evidence found (no assessment)	0	Synopsis Link