ISSN:
1573-5052
Keywords:
Algae
;
Baltic
;
Coexistence
;
Hump-backed diversity model
;
Non-equilibrium coexistence
;
Predation
;
Salinity gradient
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Data on algal species diversity from six areas along the Swedish coast, differing in salinity, length of growth period and grazing pressure were used to test two main predictions arising from the hump-backed model of species diversity (Grime 1973; Connell & Slatyer 1977; Tilman 1982; Fuentes & Jaksic 1988). Total number of species per m2, total biomass per m2 and primary production values for each species were calculated for 175 samples. Wave exposure was used as a measure of disturbance. The results are discussed in relation to stress (salinity and light) and disturbance factors (wave effects, ice scouring and grazing). A hump-backed model of species diversity, in relation to biomass per m2 was found for all investigated areas. A similar response was also observed along local exposure gradients, with higher biomass and lower species numbers found at the sheltered sites compared to the more exposed ones. The most diverse communities were found at sites with intermediate wave exposure and in communities composed of species with intermediate primary production. It is suggested that the frequency of physical disturbance and severeness of stress strongly affects algal diversity and competition by determining the time interval over which successional replacement of species can occur. This lends support to the non-equilibrium view of community structure giving rise to humpbacked species diversity curves.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00031698
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