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Environmental fluctuations, productivity, and species diversity: An experimental study
1Department of Microbiology, King's College London, Kensington Campus (University of London), Campden Hill Road, W8 7AH, London, England.
Microbial Ecology
|November 9, 2013
Summary
Environmental fluctuations impact species diversity differently based on growth rates. Low growth rates lead to decreased diversity, while high growth rates increase species diversity in microbial communities.
Area of Science:
- Ecology
- Microbiology
- Environmental Science
Background:
- Environmental fluctuations are known to influence species diversity, but their precise effects remain debated.
- Previous hypotheses on this topic have often yielded seemingly contradictory results.
Purpose of the Study:
- To investigate the relationship between environmental fluctuations and species diversity in microbial communities.
- To reconcile opposing hypotheses by examining the role of growth rates.
Main Methods:
- Studied naturally occurring microbial communities (bacteria, flagellates, ciliates) in continuous cultures.
- Manipulated productivity levels (low and high) and imposed periodic fluctuations by medium replacement.
- Mimicked resource demand/supply ratio changes through these fluctuations.
Main Results:
- At low growth rates, environmental fluctuations decreased species diversity.
- At high growth rates, environmental fluctuations increased species diversity.
- Fluctuations prevented slower-growing species survival at low growth rates.
Conclusions:
- Environmental fluctuations have a dual effect on species diversity, contingent on community growth rates.
- Low growth rates amplify the negative impact of fluctuations by excluding slower species.
- High growth rates benefit from fluctuations by reducing competitive exclusion and promoting diversity.
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