by Zeina Mohammed, University of Virginia
If you're wondering why squirrels seem to vastly outnumber raccoons—or why certain car brands dominate city streets—a team of University of Virginia researchers may be able to help.
Some species are abundant while most are rare. For nearly a century, scientists have sought a mathematical model to describe this pattern, the "hollow curve" species-abundance distribution, found universally within ecological communities. A recent breakthrough by a team within UVA's Department of Biology seems to have finally cracked this ecological puzzle.
By analyzing 30,000 datasets ranging from the distribution of tree species across the United States to bacterial communities living in the human gut, they found that a model called the "powerbend distribution" accurately describes the species abundance across plant, animal and microbial communities. Their findings were published recently in the journal Nature Communications.
The species-abundance distribution is one of ecology's oldest and most universal laws, serving as a cornerstone of many biodiversity theories and ecological models.
"This is the first study to comprehensively examine all types of organisms, large and small," said Martin Wu, UVA professor of biology and a co-author of the study. "We found that the powerbend distribution consistently fits communities of all life forms, habitats and abundance scales."
This helps quantify the general trend of a few abundant species making up large parts of the community, while the rest is made up of rarer species. These trends hold in nature and human societies alike, Wu notes.
