Disturbance and organization of macroalgal assemblages in the Northwest Atlantic

By A. Chapman, Craig R. Johnson. Hydrobiologia, 2004

141 citations recorded by the source corpus.

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.

Subfields: Ecology, Oceanography

View Paper: https://www.semanticscholar.org/paper/f83f9aa5035c564b55988473e7efc2d6a0af75ef

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In Ecology

1. R. Scheibling
2. S. Ling
3. P. Gagnon
4. S. Hawkins
5. K. Bischof
6. S. Dudgeon
7. C. Wiencke
8. U. Karsten

In Oceanography

1. R. Scheibling
2. Maria Byrne
3. C. Wiencke
4. K. Bischof
5. P. Gagnon
6. U. Karsten
7. M. Roleda
8. S. Ling

Citations in the corpus

• The importance of water‐retaining features for biodiversity on artificial intertidal coastal defence structures (2013, background): “…on artificial structures, but are ubiquitous features of natural rocky shores where they can support greater bio-diversity and different communities than the surrounding emergent rock habitat (Goss-Custard et al. , 1979; Chapman & Johnson, 1990; Firth & Crowe, 2008, 2010; Firth et al. , 2009).”
• The Population Biology of Large Brown Seaweeds: Ecological Consequences of Multiphase Life Histories in Dynamic Coastal (2006, background): “Survival curves for several species (Figure 2b), therefore, are indicative only because there is such wide variation in survival depending on conditions (Chapman & Johnson 1990, Wright et al. 2004).”
• Seasonal variation in movement, aggregation and destructive grazing of the green sea urchin (Strongylocentrotus droebachiensis) in relation to wave action and sea temperature (2007, background): “Xuctuations in abundance of the green sea urchin Strongylocentrotus droebachiensis mediate the transition between two community states: kelp beds and urchin barrens (Chapman and Johnson 1990).”
• BIODIVERSITY LOSS AND ECOSYSTEM FUNCTIONING: DISTINGUISHING BETWEEN NUMBER AND IDENTITY OF SPECIES (2005, background): “…of feeding (Steneck and Watling 1982, Hawkins and Hartnoll 1983, Hawkins et al. 1989, Hill and Hawkins 1991) and different dietary preferences (Lubchenco 1978, Watson and Norton 1985, Imrie et al. 1989, Chapman and Johnson 1990) and might be expected to affect algal assemblages in different ways.”
• Temporal variation in community interfaces: kelp-bed boundary dynamics adjacent to persistent urchin barrens (2004, background): “Such areas, referred to as urchin barrens (Lawrence 1975), have both low diversity (but see Bégin et al. 2003) and low productivity, although the abundance and diversity of coralline algae can be quite high (Steneck 1983, 1986; Chapman and Johnson 1990; Scheibling and Hatcher 2001).”
• A comparison of epifauna and epiphytes on native kelps (Laminaria species) and an invasive alga (Codium fragile ssp. tomentosoides) in Nova Scotia, Canada (2006, background): “tem of the Northwest Atlantic Ocean is generally dominated by kelps; Laminaria longicruris (Lamouroux) and L. digitata (Hudson) Lamouroux (hereafter Laminaria) are the dominant species in eastern Canada ( Chapman and Johnson 1990 ).”
• Establishment of the long-spined sea urchin (Centrostephanus rodgersii) in Tasmania: first assessment of potential threats to fisheries (2005, background): “…trigger a shift from dense and diverse macroalgae beds to sea urchin ‘barrens’ habitat largely devoid of macroalgae, few organisms have had as much impact on shallow temperate reef systems worldwide as sea urchins (Lawrence 1975; Chapman and Johnson 1990; Jackson et al. 2001; Steneck et al. 2002).”
• Detection of alternative stable states in marine communities (2004, background): “Chapman and Johnson (1990) hypothesized the switch from coralline barrens to kelp in the northwest Atlantic occurs when urchin grazing is drastically reduced by mass mortality events caused by water-borne pathogens (also see Mann, 1977; Scheibling et al., 1999 ). The reverse switch from kelps to co”
• A boom–bust phylum? Ecological and evolutionary consequences of density variations in echinoderms (2009, background): “…(Scheibling and Hennigar 1997), and there is evidence for increased recruitment during intermittently favorable environmental conditions (e.g., Chapman and Johnson 1990, Scheibling and Hatcher 2007) and for outbreaks being sustained by densityenhanced fertilization success (Wahle and Peckham…”
• Kelp forest ecosystems: biodiversity, stability, resilience and future (2002, background): “…forests in the western North Atlantic have been invaded by the green alga Codium fragile, an introduced competitor that could replace the kelp species in this region, which have a long history of resilience and dominance (Fig 5; Chapman & Johnson 1990; R.E. Scheibling, personal communication 2001).”
• The genus Laminaria sensu lato : recent insights and developments (2008, methodology): “In other areas, such as the NW Atlantic (e.g. Scheibling, 1986; Chapman & Johnson, 1990; but see Himmelman et al., 1983) and the NE Atlantic (Markham & Munda, 1980; Leinaas & Christie, 1996), Laminaria species constitute the largest and thus final successional stage.”
• Effects of native and invasive macroalgal canopies on composition and abundance of mobile benthic macrofauna and turf-forming algae (2007, unknown): “digitata (Chapman and Johnson, 1990).”