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Diversity in Relation to Body Size in Mammals: A Comparative Study
The American Naturalist
|March 27, 2018
Summary
Species body size distributions are often right-skewed. This study found that large mammal radiations tend to be small-bodied, suggesting more ecological niches are available for smaller species.
Area of Science:
- Evolutionary Biology
- Ecology
- Mammalogy
Background:
- Species body size distributions frequently exhibit right-skewed patterns.
- A negative correlation is often observed between species richness and mean body size within taxonomic groups.
- Potential explanations include random evolutionary processes, adaptation to a small optimal size, or high speciation rates in small-bodied taxa.
Purpose of the Study:
- To investigate the relationship between body size and species diversity in mammals.
- To test alternative hypotheses explaining body size distributions and diversity patterns.
Main Methods:
- Utilized body mass data for approximately 65% of global mammal species.
- Employed phylogenetically independent contrasts to account for evolutionary relationships and clade age.
Main Results:
- Body size was not found to be a universal correlate of species diversity.
- Significant radiations of mammal species were predominantly characterized by smaller body sizes.
- This pattern supports the hypothesis that smaller body sizes are associated with a greater number of available ecological niches.
Conclusions:
- The study provides evidence that the number of available ecological niches may be greatest for small-bodied taxa.
- The findings suggest that evolutionary and ecological factors favoring diversification are more prevalent for smaller mammals.
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