Observations of algal zonation resulting from competition

Hruby, Thomas

doi:10.1016/0302-3524(76)90045-1

Cited by 24 publications

(14 citation statements)

References 7 publications

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“…In another experiment (Hawkins 1979) selective removal of L. digitata below the F. serratus and Himanthalia elongata zones, resulted in both Himanthalia and F. serratus establishing themselves in greater quantity lower down the shore. In the sub-tidal, Hruby (1976) attributed control of the lower limit of Iridaea cordata to competitive interactions with more rapidly growing laminarians. These results suggest the balance in competitive ability switches from one species to the next at zonal boundaries low on the shore -in keeping with the hypotheses of Pielou (1974) and Chapman (1973Chapman ( , 1974.…”

Section: Discussionmentioning

confidence: 99%

Preliminary Canopy Removal Experiments in Algal Dominated Communities Low on the Shore and in the Shallow Subtidal on the Isle of Man

Hawkins¹,

Harkin²

1985

Botm

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The algal dominated communities immediately above and below the low-water spring level on a moderately exposed Manx shore were investigated by canopy removal experiments. Fucus serratus, Laminaria digitata and L. hyperborea were removed. Competition was shown to be important in determining the zonation of L. digitata and the distribution along the wave exposure gradient of other species such as Alaria esculenta, Desmarestia aculeata and D. viridis, and L. saccharina. Many species of algal epiphytes were early colonizers of canopy removal areas suggesting that competition from canopy algae usually restricts them to an epiphytic habit. The results indicate that interactions between macrophytes are much more important than grazing in structuring these communities.

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Section: Discussionmentioning

confidence: 99%

Preliminary Canopy Removal Experiments in Algal Dominated Communities Low on the Shore and in the Shallow Subtidal on the Isle of Man

Hawkins¹,

Harkin²

1985

Botm

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“…These patterns, summarized primarily from qualitative observations on shores protected or semi-protected from wave exposure, suggest that such non-overlapping distributions with high within-zone abundances of the characteristic species are the norm for the region. Shorelines with these attributes have been the focus of studies on the causes of zonal boundaries (Doty, 1946;Lebednik, 1973;Hruby, 1976;Hodgson, 1980;Foster, 1982a). Doty (1946) suggested that zonal boundaries may be entirely set by differences in physiological tolerance along the intertidal exposure gradient.…”

Section: Organization At Sites With Distinct Zonesmentioning

confidence: 99%

“…Doty (1946) suggested that zonal boundaries may be entirely set by differences in physiological tolerance along the intertidal exposure gradient. More recent studies (Hruby, 1976;Hodgson, 1980;Foster, 1982a) have generally concluded that lower limits are set by competition with plants below, and upper limits by physiological tolerance. Underwood (1980) has pointed out that many such experiments, especially on upper limits, have failed to consider alternative explanations such as lack of dispersal into higher areas on the shore.…”

Section: Organization At Sites With Distinct Zonesmentioning

confidence: 99%

Organization of macroalgal assemblages in the Northeast Pacific: the assumption of homogeneity and the illusion of generality

1990

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Evidence for the geographic generality of the causes of intertidal zonation and the indirect effects of a 'keystone' predator, the sea otter, on subtidal kelp assemblages was examined. Most research on intertidal algal assemblages has been done at a few protected sites where zonation is distinct. Surveys of wave-exposed intertidal sites in central and northern California show that assemblage structure is highly variable. This indicates that our present understanding of assemblage organization, including the effects of mussel-algal interactions, may not be widely applicable. Surveys of kelp forest habitat along the entire coast of California suggest that deforestation by sea urchins is uncommon in the absence of sea otters. These examples indicate that the generality of commonly accepted causes of algal assemblage structure in the Northeast Pacific may be an illusion based on assumptions of environmental homogeneity.

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“…More than 25 years ago, Burrows & Lodge (1951, 1953 found that the removal of Ascophyllum nodosum in the 'Fucus-dominated zone' allowed the downward extension of Fucus vesiculosus-a somewhat morphologically similar species occurring immediately above the band of Ascophyllum-and the upward extension of F. serratus. In California, Hruby (1976) and Foster (1982) documented strongly asymmetric competitive interaction between Laminaria and Iridaea, but within the Iridaea band there was a grazing-mediated symmetric competitive interaction between Ulva and Iridaea. Also in California, Dayton (1975aDayton ( , 1975b has described competitive displacement between Hedophyllum and Lessoniopsis which alters according to the amount of wave action.…”

Section: Zonation Of Algal Morphologies and The Symmetry Of Competitimentioning

confidence: 99%

Patterns of organizations of intertidal and shallow subtidal vegetation in wave exposed habitats of central Chile

Santelices

1990

Hydrobiologia

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Wave-exposed rocky intertidal habitats of central Chile exhibit zonation of algal morphologies rather than strict patterns of species zonation. In low shore areas, there is a vertical sequence of perennial belts of calcareous crusts, kelp-like forms and expanded cushions or non-calcareous crusts. The calcareous crusts are represented by species of Mesophyllum, the kelp-like forms include Lessonia nigrescens and Durvillaea antarctica, while the cushions are represented by Gelidium chilense and G. lingulatum and the noncalcareous, expanded crusts by Codium dimorphum. Thin and thick blades, represented by Iridaea laminarioides, Ulva rigida and Porphyra columbia and filamentous forms including Ceramium rubrum, Centroceras clavulatum and Polysiphonia spp. are more patchy than the lower, perennial belts. They may, however, form distinct temporal monocultures at upper intertidal levels. Upper and lower limits of the various zones are set by interactions of several factors, the relative importance of which can change seasonally. When some of the factors restricting species distribution are experimentally removed, other interactions among factors become limiting.Within each zone, species are morphologically similar, with the abundance of species being regulated by symmetric competitive interactions. Competition is often asymmetric at the boundaries of zones except when adults of small-sized forms interact with morphologically similar juveniles of larger forms. Irrespective of their extremely different morphologies, the permanent, zone-forming algal species generally combine escape from grazers or defensive adaptations with clear competitive abilities. Nevertheless, there is a clear competitive hierarchy which is expressed in vertical displacements and zonation. The lowershore habitats could potentially be occupied by any of the different types of algae. Fast growth and large size allow the kelps to occupy this zone pushing the calcareous crust dominated-zone down into shallow subtidal areas and displacing the cushions and fleshy crusts into the low and middle intertidal regions. In turn, these last forms can displace thick and thin foliose forms and filaments to upper levels on the shore. Displaced forms may exist as patches at various levels of the shore.

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Observations of algal zonation resulting from competition

Cited by 24 publications

References 7 publications

Preliminary Canopy Removal Experiments in Algal Dominated Communities Low on the Shore and in the Shallow Subtidal on the Isle of Man

Preliminary Canopy Removal Experiments in Algal Dominated Communities Low on the Shore and in the Shallow Subtidal on the Isle of Man

Organization of macroalgal assemblages in the Northeast Pacific: the assumption of homogeneity and the illusion of generality

Patterns of organizations of intertidal and shallow subtidal vegetation in wave exposed habitats of central Chile

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