Abstract
Seemingly opposing hypotheses concerning the effects of environmental fluctuations on species diversity were shown to complement one another. Studies were made on naturally occurring microbial communities growing in continuous cultures, under both low and high productivity levels. The communities consisted of species of bacteria, protozoan flagellates, and protozoan predators (sarcodinians and ciliates). Fluctuations were imposed by periodically removing a portion of the culture and refilling with sterilized medium. They were designed to mimic the effect of fluctuations periodically decreasing the demand/supply ratio of the community for the available resources. It was found that when growth rates were low (either because of low productivity levels or because of low intrinsic growth rates of the organisms concerned), fluctuations decreased species diversity, whereas when growth rates were high, fluctuations increased species diversity. It is suggested that fluctuations decrease diversity when growth rates are low because they prevent slower growing species from surviving, and increase diversity when growth rates are high because they decrease the extent of competitive domination and exclusion.
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References
Bormann FH, Likens GE (1979) Catastrophic disturbances and the steady state in northern hardwood forests. Am Sci 67:660–669
Caswell H (1976) Community structure: a neutral model analysis. Ecol Monogr 46:327–354
Clements FE (1905) Research methods in ecology. University Publishers, Lincoln
Connell JH (1978) Diversity in tropical rain forests and coral reefs. Science 199:1302–1310
Connell JH (1979) Tropical rain forests and coral reefs as open nonequilibrium systems. In: Anderson RM, Turner BD, Taylor LR (eds) Population dynamics. Blackwell, Oxford, pp 141–163
Darwin C (1859) The origin of species. Murray, London
Dobzhansky T (1950) Evolution in the tropics. Am Sci 38:209–221
Duncan DB (1955) Multiple range and multiple F tests. Biometrics 11:1–42
Eddison JC, Ollason JG (1978) Diversity in constant and fluctuating environments. Nature 275:309–310
Edwards AL (1970) Experimental design in psychological research. Holt, New York
Hill MO (1973) Diversity and evenness: a unifying notion and its consequences. Ecology 54:427–432
Huston M (1979) A general hypothesis of species diversity. Am Nat 113:81–101
Jahn TL (1949) How to know the protozoa. WMC Brown Co, Iowa City, Iowa
Klopfer PH (1959) Environmental determinants of faunal diversity. Am Nat 93:337–342
Kudo RR (1954) Protozoology, 4th ed. Charles C Thomas, Illinois
Levin SA (1974) Dispersion and population interactions. Am Nat 108:207–228
Levin SA (1976) Population dynamic models in heterogenous environments. Ann Rev Ecol Syst 7:287–310
Levin SA, Paine RT (1974) Disturbance, patch formation, and community structure. Proc Natl Acad Sci USA 71:2744–2747
Loucks OL (1970) Evolution of diversity, efficiency and community stability. Am Zool 10:17–25
MacArthur RH (1965) Patterns of species diversity. Biol Rev 40:510–533
MacArthur RH (1969) Patterns of communities in the tropics. Biol J Linn Soc 1:19–30
Odum EP (1969) The strategy of ecosystem development. Science 164:262–270
Peet RK (1974) The measurement of species diversity. Ann Rev Ecol Syst 5:285–307
Pianka ER (1966) Latitudinal gradients in species diversity: a review of concepts. Am Nat 100:33–46
Pielou EC (1966) The measurement of diversity in different types of biological collection. J Theor Biol 13:131–144
Pielou EC (1975) Ecological diversity. Wiley, New York
Sanders HL (1968) Marine benthic diversity: a comparative study. Am Nat 102:243–286
Sanders HL (1969) Benthic marine diversity and the stability-time hypothesis. In: Woodwell GM, Smith HH (eds) Diversity and stability in ecological systems. Brookhaven Symp in Biol, Brookhaven Natl Lab, pp 71–80
Shannon CE, Weaver W (1949) The mathematical theory of communication. University Press, University of Illinois, Urbana, Illinois
Simpson EH (1949) Measurement of diversity. Nature 163:688
Slobodkin LB, Sanders HL (1969) On the contribution of environmental predictability to species diversity. In: Woodwell GM, Smith HH (eds) Diversity and stability in ecological systems. Brookhaven Symp in Biol, Brookhaven Natl Lab, pp 82–95
Welkowitz J, Ewen RB, Cohen J (1971) Introductory statistics for the behavioural sciences. Academic Press, New York
Whittaker RH (1972) Evolution and measurement of species diversity. Taxonomy 21:213–251
Whittaker RH (1977) Evolution of species diversity in land communities. Evol Biol 10:1–67
Williams LG (1964) Possible relationships between plankton-diatom species numbers and water quality estimates. Ecology 45:809–823
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Rashit, E., Bazin, M. Environmental fluctuations, productivity, and species diversity: An experimental study. Microb Ecol 14, 101–112 (1987). https://doi.org/10.1007/BF02013016
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DOI: https://doi.org/10.1007/BF02013016