Refugial Laminaria Abundance and Reduction in Urchin Grazing in Communities in the North-West Atlantic
A literature review and new data are used to clarify geographical patterns of community response to release from heavy grazing by green sea urchins, Strongylocentrotus droebachiensis (O.F. Müller) within the north-west Atlantic region. Large geographical areas identified where urchin-removal experim...
Published in: | Journal of the Marine Biological Association of the United Kingdom |
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Main Author: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Cambridge University Press (CUP)
1991
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Online Access: | http://dx.doi.org/10.1017/s0025315400053510 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315400053510 |
Summary: | A literature review and new data are used to clarify geographical patterns of community response to release from heavy grazing by green sea urchins, Strongylocentrotus droebachiensis (O.F. Müller) within the north-west Atlantic region. Large geographical areas identified where urchin-removal experiments have not been conducted are the Passamaquoddy Bay area of the northern Bay of Fundy, the south and west coasts of Newfoundland, and southern Labrador. Within the north-west Atlantic region, there has been variation in the degree of domination by Laminaria species of post-urchin-removal communities. This is probably due, at least in part, to variation in the availability of Laminaria populations in refugia from urchin grazing. The following hypothesis is developed and given a preliminary test: in eastern Newfoundland, the absence of refugial Laminaria longicruris populations is due to periodic ice-scour. Despite the absence of significant Laminaria populations following short-term (<5 years) urchin-removal experiments in some areas, it is suggested that Laminaria spp. may be the natural, long-term community dominants in the absence of significant urchin grazing throughout the region. In view of the logistic problems involved in conducting long-term (6–15 years) urchin-removal experiments, it is suggested that urchin-removal/Laminaria-seeding experiments should be conducted within this region. |
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