Changes in the structure of a New England (USA) kelp bed the effects of an introduced species?
Year: 1992
Type: article
Abstract: Since its first observation in the Gulf of Maine (Northwest Atlantic) in 1987, the epiphytic bryozoan Membranipora membranacea has become the dominant epiphyte on laminarian kelps.This note describes changes in the structure of a kelp bed at Cape Neddick ( M a n e , USA) after the coincident increase of M. membranacea, evaluates the potential causes of the observed changes, and documents the shortterm recovery of the kelp bed.Percent cover, length and density of kelps decreased significantly during 1989 through 1991 The dispersion of Laminaria spp.within the kelp bed was clumped on each sampling date at a large spatial scale (meters), while the distribution of Laminana spp.changed from a random pattern to a clumped d~stribut~on on a smaller spatial scale (0.25 m').There were no consistent differences in storm intensity between years; densities of herbivores within the kelp bed were low and also have not changed between years.The coverage of M. membranacea on laminarian kelps increased 3-fold from 1989 to 1990, and the total coverage of other epiphytes decreased.It appears that the presence of M. membranacea on kelps has contributed to the defoliation of the kelp bed at Cape Neddick.This phenomenon may have important consequences to organisms that utilize kelps as habitat and shelterIn fall 1990 we noticed changes in kelp beds in the southern Gulf of Maine (Northwest Atlantic) at the Isles of Shoals, and off the coasts of New Hampshire and southern Maine, USA, that consisted of increased abundances of the epiphytic bryozoan Membranipora n~embranacea and the decrease in both density and size of kelp plants within these beds.The physical structure of these beds appeared to change dramatically from being dominated by large laminarian kelps to containing many broken stipes with few intact laminae.We decided to focus our studies on a previously persistent kelp bed at Cape Neddick, Maine, since this kelp bed had been under monthly observa-
Source: Marine Ecology Progress Series
DOI: 10.3354/meps088303
Authors: WJ Lambert, PS Levin, J Berman
Institutions: University of New Hampshire, University of St Andrews
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
Open Access status: bronze
Funder: National Science Foundation
OpenAlex ID: W2025300252