Title: The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder
Identifier: easternberingsea00hood (find matches)
Year: 1981 (1980s)
Authors: Hood, D. W. (Donald Wilbur), 1918-; Calder, John A; United States. Office of Marine Pollution Assessment; United States. Bureau of Land Management
Subjects: Oceanography Bering Sea.
Publisher: (Rockville, Md. ?) : U. S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Office of Marine Pollution Assessment ; Seattle, Wash. : Distributed by the University of Washington Press
Contributing Library: Penn State University
Digitizing Sponsor: LYRASIS Members and Sloan Foundation

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1114 Benthic biology o o CO UJ o LU D. CO Lil > I- < _l O 30 25 20- AKUN ISLAND AMAK ISLAND
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OTTER ISLAND ST. GEORGE ISLAND 4 5 6 NUMBER OF SAMPLES 10 Figure 64-3. Species-area curves of mollusks in quadrats collected in the intertidal region at four islands in the Bering Sea. The shores of two islands (Otter and St. George) are frequently scoured by sea ice. Islands leveled off at the lowest species counts (4 and 7; Fig. 64-3); the curve for Akun Island increased to the highest count (27). The curve for Amak Island reflected an intermediate species richness. Therefore, the results of the comparisons of molluscan species- area curves between islands paralleled results of the species counts of most other major taxa (Figs. 64-2 and 64-3). Species-importance curves In order to examine the distribution of biomass (wet weight) among mollusks, I used species-impor- tance (=dominance-diversity) curves (Whittaker 1965, 1970, 1972). Species-importance curves are constructed by plotting the importance (usually in terms of abundance, biomass, coverage, or productiv- ity) of a species on the ordinate (on a logarithmic scale) opposite its rank in the measure of importance selected on the abscissa, on which species are ranked from most to least important. Whittaker (1965) has found that, at least in terrestrial plant communities. three of the measures of importance commonly used by various authors, coverage, biomass, and produc- tivity, produce species-importance curves which differ in steepness but not in form. BatzU (1969) has claimed that in the rocky intertidal region, biomass is a better measure of importance than number of individuals. Three theoretical distributions of importance among species occur frequently in the literature; May (1975) relates them. The most uniform is the broken-stick distribution, and the least uniform is the geometric series; the lognormal distribution falls between these two. The form of each distribution when plotted as importance versus rank is shown in May's Figure 1 (1975). Two of the distributions (the broken stick and the geometric series) reflect, in theory, biological mechanisms (types of competition) that structure the community. The lognormal distribution arises when species-importance relation- ships are controlled by the "interplay of many independent factors" (May 1975).

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