Limpet grazing and loss of Ascophyllum nodosum canopies on decadal time scales
Authors: Davies, A.J., Johnson, M.P. and Maggs, C.A.
Journal: Marine Ecology Progress Series
Volume: 339
Pages: 131-141
ISSN: 0171-8630
DOI: 10.3354/meps339131
Abstract:The role of limpet grazing in preventing the development of algal canopies is a recurrent theme in intertidal ecology. Less is known about interactions of limpets with the long-term dynamics of established canopies. Aerial photographs indicate that intertidal canopy cover has declined over the past 44 yr in Strangford Lough, Northern Ireland. There has been a loss of the previously continuous cover of Ascophyllum nodosum (L.) Le Jolis in the mid-shore. A barnacle-dominated assemblage now fills gaps in the A. nodosum canopy. The rates at which barnacle patches become established and grow have increased since 1990. Changes in canopy cover have been accompanied by increases in limpet densities since the 1980s. Measurements between 2003 and 2004 showed no increase in length of A. nodosum fronds when limpets Patella vulgata had access to the algal holdfasts. In contrast, when limpets were experimentally excluded from the holdfasts, there was net frond growth. In the Isle of Man, which is climatically similar to Strangford Lough but has fewer limpets, growth occurred regardless of limpet grazing. The breaking force for A. nodosum declined with increasing local densities of limpets. A. nodosum is a sheltered shore species, potentially vulnerable to changes in wave exposure. There is no evidence, however, that Strangford Lough has become windier over the past 3 decades. Variation in wave exposure among locations within the lough was not related to rates of barnacle patch creation or expansion. Limpet population density has increased following a series of mild winters. Climate change may have a role in causing canopy loss, not by direct effects on the growth of fucoids, but by increasing the severity of grazing through changes to limpet populations. © Inter-Research 2007.
Source: Scopus
Limpet grazing and loss of <i>Ascophyllum nodosum</i> canopies on decadal time scales
Authors: Davies, A.J., Johnson, M.P. and Maggs, C.A.
Journal: MARINE ECOLOGY PROGRESS SERIES
Volume: 339
Pages: 131-141
ISSN: 0171-8630
DOI: 10.3354/meps339131
Source: Web of Science (Lite)