First study to compare dietary signatures of African and South American mammals in quest to reconstruct ancient ecosystems finds need for revisions — ScienceDaily

Closed-canopy rainforests are a vital part of the Earth’s modern ecosystems, but tropical plants don’t preserve well in the fossil record so it is difficult to tell how long these habitats have existed and where rainforests might have once grown. Instead, scientists look to the diets of extinct animals, which lock evidence of the vegetation they ate into their teeth. A new study led by scientists at the American Museum of Natural History finds that the paradigm used to identify closed-canopy rainforests through dietary signatures needs to be reassessed. The findings are published this week in the journal Proceedings of the National Academy of Sciences.

“The Amazon is the world’s most diverse rainforest, home to one in 10 known species on Earth,” said Julia Tejada-Lara, who led the study as a graduate student at the Museum and Columbia University. “Closed-canopy rainforests have been proposed to occur in this area

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Seasonal dietary changes increase the abundances of savanna herbivore species — ScienceDaily

African savannas are renowned for their huge diversity of wildlife, yet some animal species are much more abundant than others. What causes these differences?

For herbivore species — plant-eating animals like antelope, zebra and elephants — the challenge lies in both obtaining enough food to eat throughout the year, while also avoiding predation by carnivores.

One way to obtain enough food — and which works extremely well in places like the Serengeti — is to migrate over long distances and track the areas where the best food is available through the seasonal cycle. This works best for grass eating or ‘grazer’ species such as wildebeest and zebra.

On the other hand, being extremely large like an elephant greatly reduces predation risk, with their big bodies also meaning that they can eat whatever they like, because there is lots of time to digest foods as they move through their long gut

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