Are we in a mass extinction event? New UA study takes a holistic look at biodiversity loss

Many experts have concluded the planet is in the midst of a mass extinction event — during which large numbers of plant and animal species die off in a relatively short time. But a new study from a pair of University of Arizona researchers suggests an accurate assessment may require different methodology.

The research involved analyzing the rates, patterns and causes of recent extinctions across over 900 species. Rates vary among organisms — according to the paper, extinctions are more frequent in mollusks but more rare among arthropods.

Researcher John Wiens is a biology professor at the UA.

“There's been lots of studies on recent extinctions, but they've tended to focus on individual groups, like there's been great studies on birds and great studies on plants. But there have been very few that have kind of tried to look at everything," he said.

Author Kristen Saban, a former UA student, says researchers need to be careful on how they extrapolate data when looking into past extinctions.

“I would say broadly, biodiversity loss is one of the greatest threats that is currently facing humanity. And that's documented in these recent extinctions. But it's not quite a doomsday scenario yet," she said.

Wiens says evidence of a mass extinction relies on analysis of data from the past 500 years. But he says that’s unreliable, because past extinctions were largely tied to invasive species. And current projections must be based on the most significant modern threat, which is habitat loss.