A study out today in Biology Letters shows that global warming will likely drive several species of primates closer to extinction by increasing the severity and frequency of El Niño and La Niña events (the El Niño Southern Oscillation, ENSO).
Eric Post and graduate student Ruscena Wiederholt of Penn State examined population data on four species of threatened New World monkeys: muriquis (or woolly spider monkeys) in Brazil, woolly monkeys in Colombia, Geoffroy’s spider monkeys on Barro Colorado Island in Panama, and red howler monkeys in Venezuela. The scientists compared monkey population levels and the amounts of leaves and fruits available as monkey food with the frequency and duration of ENSO events.
Their data showed that howler monkeys, which eat mostly leaves, declined during El Niño years, but that the other monkeys, which derive part or all of their diet from fruit, showed a year lag in their corresponding decline.
Global warming is predicted to exacerbate the effects of the ENSO, in which ocean waters in the southern hemisphere warm (El Niño) and cool (La Niña), creating correlated terrestrial changes in weather patterns, such as flooding, droughts and severe storms. The authors show that ENSO events greatly alter the availability of leaves and fruits, creating greater mortality and a consequential population decline. As Wiederholt said in a press release:
We know very little about how climate change and global warming are affecting primate species. Up to one third of primate species are threatened with extinction, so it is really crucial to understand how these changes in climate may be affecting their populations.
Read the Times Online’s story here.
Ruscena Wiederholt, & Eric Post (2009). Tropical warming and the dynamics of endangered primates Biology Letters