The El Niño triggers declines in primates in the New World, suggesting an increase in these events caused by global warming could be devastating.

Ruscena Wideerholf and Eric Post, of Penn State University, looked at how El Niño influences the populations of muriqui (Brachyteles hypoxanthus), woolly monkey (Lagothrix lagotricha), Geoffroy’s spider monkey (Ateles geoffroyi), and red howlers (Alouatta seniculus). In Biology Letters, they report that all four experienced either intimidate or one year lagged negative impacts on their populations.

“Our results indicate that global climate change and increased El Niño events could pose a serious threat to ateline primates” they write. “Given that the status of many primate species is already precarious, in the face of continued global change, further studies to quantity the effects of climate and environmental variability on primate species are needed.”

The El Niño Southern Oscillation (ENSO) is a change in sea surface temperatures in the Pacific.

“El Niño events are expected to increase in frequency with global warming,” says Post (press release). “This study suggests that the consequences of such intensification of ENSO could be devastating for several species of New World monkeys.”

Image: critically endangered northern muriqui / Carla B. Possamai / K.B. Strier