A continental scale evaluation of the role of limpet grazing on rocky shores.
It is critical for our knowledge of biodiversity and ecosystem processes to understand how individual species contribute to ecosystem processes and how these contributions vary in space and time. We used a manipulative field experiment in five locations over 17 degrees of latitude [from southern Portugal to the Isle of Man (British Isles)] to determine the relative response of rocky intertidal algal assemblages released from control by the grazing of limpets. Response ratios showed that when limpets were removed there was a trend of effects from north to south. In the north, grazing had a strong effect on algal assemblages, but removing grazers reduced spatial variability in assemblages. In the south, the effect of limpet grazing was far weaker and removal of grazers had a much reduced impact on spatial variability. Here we show a clear trophic control of an ecosystem in that grazing by limpets not only determines macroalgal abundance overall but also modifies ecosystem stability via variability in cover of algae.
Coleman
Ross A
RA
School of Biological Sciences, University of Southampton, SO16 7PX, Southampton, UK. rcoleman@usyd.edu.au
Underwood
Antony J
AJ
Benedetti-Cecchi
Lisandro
L
Aberg
Per
P
Arenas
Francisco
F
Arrontes
Julio
J
Castro
João
J
Hartnoll
Richard G
RG
Jenkins
Stuart R
SR
Paula
José
J
Della Santina
Paolo
P
Hawkins
Stephen J
SJ
D000704:Analysis of Variance; D000818:Animals; D005247:Feeding Behavior; D008974:Mollusca / Q000502:physiology*