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Journal ArticleDOI

Variations in Diversity within Benthic Marine Communities

01 May 1970-The American Naturalist (University of Chicago Press)-Vol. 104, Iss: 937, pp 285-300
TL;DR: A combination of the concepts of succession and the relationship between species diversity and environmental stability provides a theoretical context for predicting short-term changes in modern environments and for the interpretation of the stratigraphic record of ancient communities.
Abstract: From theoretical considerations, it is suggested that the continual occurrence of small-scale disturbances can account for part of the spatial and temporal variations of diversity within benthic marine communities. This small-scale stability hypothesis is evaluated in terms of how effectively it can serve as an explanation of variations in an intertidal community. Appreciable changes occurred at 10 of 20 sites studied in Tomales Bay from 1963 to 1967. The recurrent pattern of change at nine of these 10 sites can be readily explained by the stability hypothesis. The only difference between this explanation of diversity within communities and that between communities is the frequency and scale of the perturbations of the environment. A combination of the concepts of succession and the relationship between species diversity and environmental stability provides a theoretical context for predicting short-term changes in modern environments and for the interpretation of the stratigraphic record of ancient commu...
Citations
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Journal ArticleDOI
TL;DR: It is suggested that the "predation" and "competition" hypotheses of community organization and species diversity are complementary, and that Predator-mediated escapes by primary producers from herbivores may explain the apparent importance of interspecific competition in certain primary producer associations.
Abstract: We suggest that the "predation" and "competition" hypotheses of community organization and species diversity are complementary. Maintenance of high diversity by competition appears to be relatively more important at higher trophic levels, while maintenance of high diversity by predation seems relatively more important at lower trophic levels. Further, predation is probably the dominant organizing interaction in trophically complex communities, while competition is probably the dominant organizing interaction in trophically simple communities. These hypotheses are supported on a local scale by experimental studies in the rocky intertidal communities of New England and the West Coast. A probable consequence of its greater temporal heterogeneity (i.e., a less stable, less predictable, and more stressful environment) is that the East Coast is trophically more simple and has an increased incidence of competitive exclusion. As a result, diversity is lower on the East Coast compared with the West Coast. A simila...

1,133 citations

Journal Article
TL;DR: Using mortality as the best single measure of degree of opportunism is proposed, a definition based on mortality emphasizes the portion of the life cycle involved in adaptation through shortterm selection.
Abstract: The decline in benthic marine fauna foll owing an oil spill in West Falmouth, Massachusetts, permitted us to follow the responses of a number of polychaete and other invertebrate species to an environmental disturbance. Species with the most opportunistic life histories increased and declined at the two stations with the greatest reduction in species diversity. The stations with an intermedi ate reduction in diversity showed increases and declines of somewhat less opportunistic species. Electrophoretic studies of the malate dehydrogenase loci of the most opportunistic species, Capitella capitata, indicated short-term selecti on for a single genotype in the large populations present in Wild Harbor following the oil spill . The life histories of the most opportunistic species are summarized . Initial response to disturbed conditions, ability to increase rapidly, large population size, early maturation, and high mortality are all features of opportunistic species. Using these criteria, the species are ranked in order of decreasing degree of opportunism as: r. Capitella capita/a, 2. Polydora ligni, 3. Syllides 'Verrilli , 4. Microphthalmus aherrans, 5. Streblospio benedicti, 6. M ediomastus ambiseta. We propose using mortality as the best single measure of degree of opportunism. A definition based on mortality emphasizes the portion of the life cycle involved in adaptation through shortterm selection. Two types of marine benthic opportunists are described: r. a mixed strategy variety with obligate planktonic dispersal where selecti on wi thin local subpopulations occurs in a single generation, 2. a response-to-selection type with direct development or settlement shortly after release from brood structures all owing selection within local populations through more than one generation.

648 citations

Journal ArticleDOI
TL;DR: It is concluded that succession in the classical sense does not occur in this system because initial development was variable, residents impeded subsequent development instead of enhancing it, and there was no stable climax.
Abstract: Community development was followed for 2 1/2 to 3 1/2 years on unglazed ceramic tile plates (232 cm2), suspended horizontally beneath the Duke University Marine Laboratory dock, in Beaufort, North Carolina. Series of 3 or 4 plates were submerged at approximately the 1st of each month from May—November 1971 and from April—November 1972. Percentage cover for each species that settled and grew on the lower surface was estimated at 6— to 8—week intervals, using 75 points randomly positioned over the plate area. Samples were nondestructive; plates were resubmerged after each census. Larval recruitment was estimated at 1— to 3—week intervals on newly submerged plates. Temperature and salinity were also measured. Initial community development was relatively unpredictable. Larval recruitment patterns varied markedly from year to year and as a result, different patterns of initial community development were observed both within and between years. Instead of preparing the way for subsequent arrivals, most resident adults strongly inhibited the recruitment and growth of other species. Species varied in their ability to resist subsequent invasion as adults and in their ability to invade occupied substrate as larvae. After an unpredictable initial developmental phase, subsequent changes in species composition depended in part on the degree to which larvae were able to invade existing adult assemblages. This in turn depended on the identity of the resident adults and the identity of the invading larvae. As a result, the direction and rate of community development, dependent on the order of initial invasion and subsequent recruitment, were difficult to predict although an equilibrium number of 8—10 species/plate was often observed. Adult residence time was generally <1 year and the mortality and/or disappearance of these adults produced 20—60% free space on an approximately annual basis. This free space was usually occupied by recruits of a different species than the original occupant. The combined addition of species through larval recruitment and subtraction of species as a result of adult mortality produced dramatic changes in community structure each year. There is no reason to believe these changes will ever cease. We conclude that succession in the classical sense (Odum 1969) does not occur in this system because initial development was variable, residents impeded subsequent development instead of enhancing it, and there was no stable climax. There is good reason to believe similar processes occur in other temperate and subtropical fouling communities. We believe these communities are fundamentally different from terrestrial plant communities, where succession may occur, for 3 reasons: (1) the organisms do not alter the substrate they occupy, i.e., “prepare” it for later arrivals, (2) there is no possibility of “storing” dormant “seeds” of successional species. Colonization of free space is generally by animals which have a short—lived, even nonfeeding larvae, (3) most adults are extremely short—lived. An emerging paradigm of marine benthic community organization postulates the existence of competitive hierarchies in which 1 or a few species win in the absence of disturbances. The fouling community appears to lack such dominants.

524 citations

BookDOI
01 Jan 1985

501 citations

Journal ArticleDOI
TL;DR: An alternative to the stability-time hypothesis explaining the high benthic faunal diversities in the deep sea has been proposed by Dayton and Hessler (1972), where nonselective predation reduces competition between species thereby allowing more species to coexist.

330 citations

References
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Journal ArticleDOI
TL;DR: Information content may be used as a measure of the diversity of a many-species biological collection whereby the sample size is progressively increased by addition of new quadrats and the mean increment in total diversity that results from enlarging the sample still more provides an estimate of the Diversity per individual in the whole population.

4,415 citations

Journal ArticleDOI
TL;DR: A within-habitat analysis was made of the bivalve and polychaete components of soft-bottom marine faunas which differed in latitude, depth, temperature, and salinity, and it was indicated that species number is the more valid diversity measurement.
Abstract: In this paper a methodology is presented for measuring diversity based on rarefaction of actual samples. By the use of this technique, a within-habitat analysis was made of the bivalve and polychaete components of soft-bottom marine faunas which differed in latitude, depth, temperature, and salinity. The resulting diversity values were highly correlated with the physical stability and past history of these environments. A stability-time hypothesis was invoked to fit these findings, and, with this hypothesis, predictions were made about the diversities present in certain other environments as yet unstudied. The two types of diversity, based on numerical percentage composition and on number of species, were compared and shown to be poorly correlated with each other. Our data indicated that species number is the more valid diversity measurement. The rarefaction methodology was compared with a number of diversity indexes using identical data. Many of these indexes were markedly influenced by sample size. Good...

2,354 citations


"Variations in Diversity within Bent..." refers background in this paper

  • ...These factors are also involved in the overall stability of a community in the sense of Sanders (1968). The frequency and areal extent of the influence of such disturbances represent in a general way the level of physiological stress under which a particular...

    [...]

Journal ArticleDOI
03 Jan 1969-Science
TL;DR: Diversity peaks occur at abyssal depths of greater than 2500 meters and 100 to 200 meters and the peak at 35 to 45 meters is due to species equitability, whereas the other two peaks correspond to an increase in the number of species.
Abstract: Maximum species diversity occurs at abyssal depths of greater than 2500 meters. Other diversity peaks occur at depths of 35 to 45 meters and 100 to 200 meters. The peak at 35 to 45 meters is due to species equitability, whereas the other two peaks correspond to an increase in the number of species.

459 citations

Journal ArticleDOI
TL;DR: In this paper, temperature variation within intertidal sands was observed at two stations in Tomales Bay, California, and the annual range and seasonal trend temperature at 10 cm beneath the sand surface are similar to those in the open water of the bay.
Abstract: Temperature variation within intertidal sands was observed at two stations in Tomales Bay, California. The annual range and seasonal trend temperature at 10 cm beneath the sand surface are similar to those in the open water of the bay. The daily variation resembles that observed in terrestrial soils. Animals living in the upper 1 cm are exposed to a daily temperature range as great as three times that experienced by subtidal individuals of the same species. The animals living at 10 cm or deeper are subject to a temperature regime similar to that of the subtidal environment.

68 citations

Journal ArticleDOI
01 Jul 1967-Ecology
TL;DR: In this article, the vertical distribution of macroscopic invertebrates at two sites in Tomales Bay, California was studied and the average median depth of all species was found to be 8 cm in samples taken at low tide during daylight hours.
Abstract: This study is concerned with the vertical distribution of macroscopic invertebrates at two sites in Tomales Bay, California. Four sampling procedures were used to obtain data on more than 20,000 individuals. The infauna does not react to tidal fluctuations in water level by appreciable vertical movements in the areas studied. There is no evidence that the depth of the infauna varies with elevation in the range from 0 to 1 m above sea level. The average median depth of all species (except Phoronopsis harmeri) was found to be 8 cm in samples taken at low tide during daylight hours. Most species of the infauna and about 80% of the individuals occur in the upper 15 cm. See full-text article at JSTOR

41 citations