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<title>UTas ePrints - Disturbance and organization of macroalgal assemblages in the Northwest Atlantic</title>
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<meta content="Johnson, Craig R." name="eprints.creators_name" />
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<meta content="Disturbance and organization of macroalgal assemblages in the Northwest Atlantic
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<meta content="Northwest Atlantic; intertidal; subtidal; disturbance; biological interactions; community organization
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<meta content="Large seaweeds are often structurally dominant in subtidal and intertidal rocky shore benthic communities of the N.W. Atlantic. The mechanisms by which these algal assemblages are maintained are surprisingly different in the two habitats. In the subtidal community, kelps are dominant space competitors in the absence of strong grazing interactions. In contrast, the large perennial seaweeds of intertidal zones (fucoids and Chondrus crispus) are competitively inferior to both sessile filter feeders and ephemeral, pioneer algal species. Intertidal seaweed beds are maintained by carnivory of whelks, which reduces filter feeder populations, and by herbivorous periwinkles which reduce ephemeral algal populations. Through most of the intertidal zone, disturbance, both biological and physical, dictates which species shall compete and equilibrium conditions obtain subsequently.
The roles of subtidal consumers are quite different. Sea urchins are the major algal herbivores and these voracious animals maintain an equilibrium state in which large tracts of subtidal coralline pavement are kept free of kelp forests. Urchins do not seem to play a successional facilitative role for kelps in the way that periwinkles do for fucoids in the intertidal. Control of herbivore populations is thus a key to the maintenance of subtidal foliose algal beds. It is clear that parasitic amoebas can decimate sea urchin populations so that kelp forest dominance is assured. However, the importance of carnivory in limiting urchins in the subtidal community is unclear in the absence of appropriate manipulation experiments. It is possible that carnivorous decapods and fin fish control sea urchin populations and hence foliose algal abundance, but this must remain speculative. The seaweed-dominated state of the subtidal system is an alternative equilibrium condition to the urchin/coralline alga configuration. The structure of the kelp beds is relatively uniform in responding to frequent small-scale, infrequent large-scale, or no, disturbance.
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<meta content="Large seaweeds are often structurally dominant in subtidal and intertidal rocky shore benthic communities of the N.W. Atlantic. The mechanisms by which these algal assemblages are maintained are surprisingly different in the two habitats. In the subtidal community, kelps are dominant space competitors in the absence of strong grazing interactions. In contrast, the large perennial seaweeds of intertidal zones (fucoids and Chondrus crispus) are competitively inferior to both sessile filter feeders and ephemeral, pioneer algal species. Intertidal seaweed beds are maintained by carnivory of whelks, which reduces filter feeder populations, and by herbivorous periwinkles which reduce ephemeral algal populations. Through most of the intertidal zone, disturbance, both biological and physical, dictates which species shall compete and equilibrium conditions obtain subsequently.
The roles of subtidal consumers are quite different. Sea urchins are the major algal herbivores and these voracious animals maintain an equilibrium state in which large tracts of subtidal coralline pavement are kept free of kelp forests. Urchins do not seem to play a successional facilitative role for kelps in the way that periwinkles do for fucoids in the intertidal. Control of herbivore populations is thus a key to the maintenance of subtidal foliose algal beds. It is clear that parasitic amoebas can decimate sea urchin populations so that kelp forest dominance is assured. However, the importance of carnivory in limiting urchins in the subtidal community is unclear in the absence of appropriate manipulation experiments. It is possible that carnivorous decapods and fin fish control sea urchin populations and hence foliose algal abundance, but this must remain speculative. The seaweed-dominated state of the subtidal system is an alternative equilibrium condition to the urchin/coralline alga configuration. The structure of the kelp beds is relatively uniform in responding to frequent small-scale, infrequent large-scale, or no, disturbance.
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<h1 class="ep_tm_pagetitle">Disturbance and organization of macroalgal assemblages in the Northwest Atlantic</h1>
<p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Chapman, A.R.O.</span> and <span class="person_name">Johnson, Craig R.</span> (1990) <xhtml:em>Disturbance and organization of macroalgal assemblages in the Northwest Atlantic.</xhtml:em> Hydrobiologia, 192 (1). pp. 77-121. ISSN 0018-8158</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/1234/1/chapman-johnson.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" border="0" class="ep_doc_icon" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/1234/1/chapman-johnson.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />3437Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input value="1602" name="docid" accept-charset="utf-8" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://dx.doi.org/10.1007/BF00006228">http://dx.doi.org/10.1007/BF00006228</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">Large seaweeds are often structurally dominant in subtidal and intertidal rocky shore benthic communities of the N.W. Atlantic. The mechanisms by which these algal assemblages are maintained are surprisingly different in the two habitats. In the subtidal community, kelps are dominant space competitors in the absence of strong grazing interactions. In contrast, the large perennial seaweeds of intertidal zones (fucoids and Chondrus crispus) are competitively inferior to both sessile filter feeders and ephemeral, pioneer algal species. Intertidal seaweed beds are maintained by carnivory of whelks, which reduces filter feeder populations, and by herbivorous periwinkles which reduce ephemeral algal populations. Through most of the intertidal zone, disturbance, both biological and physical, dictates which species shall compete and equilibrium conditions obtain subsequently.
The roles of subtidal consumers are quite different. Sea urchins are the major algal herbivores and these voracious animals maintain an equilibrium state in which large tracts of subtidal coralline pavement are kept free of kelp forests. Urchins do not seem to play a successional facilitative role for kelps in the way that periwinkles do for fucoids in the intertidal. Control of herbivore populations is thus a key to the maintenance of subtidal foliose algal beds. It is clear that parasitic amoebas can decimate sea urchin populations so that kelp forest dominance is assured. However, the importance of carnivory in limiting urchins in the subtidal community is unclear in the absence of appropriate manipulation experiments. It is possible that carnivorous decapods and fin fish control sea urchin populations and hence foliose algal abundance, but this must remain speculative. The seaweed-dominated state of the subtidal system is an alternative equilibrium condition to the urchin/coralline alga configuration. The structure of the kelp beds is relatively uniform in responding to frequent small-scale, infrequent large-scale, or no, disturbance.
</p></div><table style="margin-bottom: 1em" border="0" cellpadding="3" class="not_ep_block"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Additional Information:</th><td valign="top" class="ep_row">The original publication is available at www.springerlink.com</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">Northwest Atlantic; intertidal; subtidal; disturbance; biological interactions; community organization
</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/270702.html">270000 Biological Sciences > 270700 Ecology and Evolution > 270702 Marine and Estuarine Ecology (incl. Marine Ichthyology)</a></td></tr><tr><th valign="top" class="ep_row">Collections:</th><td valign="top" class="ep_row">UNSPECIFIED</td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">1234</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Professor Craig R. Johnson</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">24 Jun 2007</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">04 Feb 2008 17:25</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=1234;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=1234">item control page</a></p>
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