Animals switch diets when climate changes

A new study conducted by the University of Florida shows that mammal-modified mammals rely on climate-related environmental changes, which contrasts with the assumption that mammals still maintain their eating habits. drink them even though the global climate heats up.

Under the direction of vertebrate palaeontologist Larisa DeSantis of the Florida Museum of Natural History, the researchers analyzed the fossil teeth of mammals found in two locations. The characteristic for two different climates in Florida: one is an ice age about 1.9 million years ago, while another is a warmer period of about 1.3 million years ago. The researchers found that the warming of the interglacial period caused major changes in the diet of animal groups living in both locations. The study is published in June 3 issue of PloS ONE magazine for field scientists.

DeSantis said: 'When people model the distribution of mammals in the future, they consider that the characteristics of mammals today will remain in the future'.

Co-author Robert Feranec - who is in charge of the vertebrate paleontology department at the New York Museum - says scientists can't predict what species will be based on their current ecology. He said: 'This research has clearly shown that there are more complex things than we thought.'

Two research sites are located on the Gulf of Florida, they have been excavated extensively. During the low frost period, nearly twice the width of Florida. But because Florida was at a low latitude, no ice sheet formed during this period. Although there is no ice in Florida, two excavation sites also show a large ecological change between the two periods.

Both sites have a number of common animal groups, which allows DeSantis, Feranec and Bruce MacFadden - who are also in charge of vertebrate paleontology at the Florida museum - to know mammals and lips How their school reacted to warming in the glacial period.

The researchers analyzed the oxygen and carbon isotopes in the enamel layer to understand the diet of medium to large animals, including many branched antelopes, deer, llamas, pigs. taps, horses, mastodons, mammoths and gomphothere - a group of extinct elephant-like animals.

The fossilized horse tooth (Equus) helps scientists detect seasonal variations in animal diets.This horse lived 1.9 million years ago during the icy period in Florida.An article published by University of Florida researchers published in PloS ONE found that ancient mammals changed their diets due to global warming in the past.(Photo: Mary Warrick, PLoS ONE)

The difference in photosynthesis of plants has given them a different proportion of carbon isotopes. For example, trees and shrubs treat carbon dioxide differently than grasses that grow in warm climates, causing them to have different carbon isotope ratios. This difference is also agglomerated in mammalian enamel, allowing scientists to determine the diet of extinct animals. The lower isotope ratio indicates that they eat leafy plants, while the higher isotope ratio indicates they have eaten grass.

The ice-place animals mostly eat tall leaves and shrubs, and the same animals in that place at the time of the ice become more omnivores , they cup grass. The increase in grass diets in these animals and elephant-like animals indicates that Florida grasslands may have expanded into the ice age.

Enamel encompasses chemical signs of plants and water that an animal eats, allowing paleontologists to understand the diet and related climatic features even though the past has passed through the line. million years. To find these signs, researchers had to run enamel samples through the mass spectrometer.

DeSantis and colleagues analyzed tooth enamel samples from 15 fossil teeth. Two of these patterns have given a glimpse into the changes in diet and climate over a fixed period of time.

She said: 'This is one of the interesting things about mammalian teeth. We can really look at the diversity of the climate every year and even millions of years ago. '

The study emphasizes the importance of fossils in understanding long-term ecological changes. While ecological studies of today's effects can only cover a limited amount of time, 'this study highlights the importance of using fossils to understand mammals and How other animals react to climate change in the past and help us gain a deeper understanding of how they change in the future. '

Refer:

DeSantis LRG, Feranec RS, MacFadden BJ (2009) Effects of Global Warming on Ancient Mammalian Communities and Their Environments.PLoS ONE 4 (6): e5750.doi: 10.1371 / journal.pone.0005750, http://dx.plos.org/10.1371/journal.pone.0005750
Source: Public Library of Science