Lemurs of Madagascar offer clues to global-warming impact

Mike Williams in the Rice University News: Global warming may present a threat to animal and plant life even in biodiversity hot spots once thought less likely to suffer from climate change, according to a new study from Rice University.

Research by Amy Dunham, a Rice assistant professor of ecology and evolutionary biology, detailed for the first time a direct correlation between the frequency of El Niño and a threat to life in Madagascar, a tropical island that acts as a refuge for many unique species that exist nowhere else in the world. In this case, the lemur plays the role of the canary in the coal mine.

Even tropical animals, such as lemurs, may be threatened by global warming, according to a new study from Rice. … Dunham said most studies of global warming focus on temperate zones. "We all know about the polar bears and their melting sea ice," she said. "But tropical regions are often thought of as refuges during past climate events, so they haven’t been given as much attention until recently.

"We're starting to realize that not only are these hot spots of biodiversity facing habitat degradation and other anthropogenic effects, but they're also being affected by the same changes we feel in the temperate zones."

…The warming of global sea temperatures may "enhance" El Niño cycles, according to the National Oceanic and Atmospheric Administration. Dunham found that in Ranomafana, contrary to expectations, El Niño makes wet seasons wetter. "When it rains heavily, lemurs are not active. They sit there and wait for the rain to stop, huddling for warmth," Dunham said. Anecdotal evidence suggested heavy rains knock fruit off the trees when lactating lemurs need it most, and may even kill trees outright.

Dunham learned from the data that cyclones making landfall have a direct negative effect on the fecundity – or potential reproductive capacity – of lemurs. The team also discovered that fecundity "was negatively affected when El Niño occurred in the period before conception, perhaps altering ovulation, or during the second six months of life, possibly reducing infant survival during weaning," they wrote.

"Madagascar's biodiversity is an ecological treasure," Dunham said. "But its flora and fauna already face extinction from rapid deforestation and exploitation of natural resources. The additional negative effects of climate change make conservation concerns even more urgent."…

A lemur in Madagascar, shot by either Visionholder or Stooof, Wikimedia Commons, under the Creative Commons Attribution ShareAlike 3.0 License.