Review of “The Past and Future Human Impact on Mammalian Diversity” (2020)


Alexandre Antonelli (writer), Daniele Silvestro (writer), Søren Faurby (writer), Samuel T. Turvey (writer), Tobias Andermann (writer).

Read in 2020.

To understand the current biodiversity crisis, it is crucial to determine how humans have affected biodiversity in the past. However, the extent of human involvement in species extinctions from the Late Pleistocene onward remains contentious. Here, we apply Bayesian models to the fossil record to estimate how mammalian extinction rates have changed over the past 126,000 years, inferring specific times of rate increases. We specifically test the hypothesis of human-caused extinctions by using posterior predictive methods. We find that human population size is able to predict past extinctions with 96% accuracy. Predictors based on past climate, in contrast, perform no better than expected by chance, suggesting that climate had a negligible impact on global mammal extinctions.

The authors note four known examples of mammalian species rediscovered after having been thought extinct, and account for this phenomenon (the “Lazarus effect”) by assigning a 1% probability to each species sighted since 1500 CE and currently listed as extinct being such a false positive. That’s a neat touch.

References here: Soft drinks and ethical nihilism.

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