In modern ecosystems, it's known that animals flourish in regions where the climate and landscape produce lush vegetation.
A new study set out to discover whether that same relationship held true 150 million years ago during the Late Jurassic when dinosaurs roamed the Earth.
"The assumption has been that ancient ecosystems worked just like our modern ecosystems," said paleontologist and lead author Timothy S. Myers, Southern Methodist University, Dallas. "We wanted to see if this was, in fact, the case."
To test the theory, Myers analyzed fossil soils from the Late Jurassic by measuring the ratios of carbon isotopes. His analysis indicated that the Jurassic soils contained high levels of CO2 from vegetation.
From that, Myers was able to infer the presence of lush plant life in certain regions during the Jurassic. The soils came from locales where scientists previously have gathered animal fossils North America, Europe and Africa. Combining the data with the known fossil sampling allowed Myers to confirm that the modern relationship between animals and vegetation held true even millions of years ago.
"Our analysis represents the first time that anyone has tried to apply ecological modeling to this relationship in the fossil record," Myers said.
Relatively few places in the world are well-sampled for terrestrial fossils, so Myers' discovery of a new use for an already existing method represents a useful tool, he said. The new use allows scientists to tap the geochemical data of soils from anywhere in the world and from other geologic time periods to infer the relative abundance of plants and animals, particularly for areas where fossils are lacking.
"This not only provides a more complete picture of the ancient landscape and climate in which ancient animals lived," Myers said. "It also illustrates that climate and biota have been ecologically connected for many millions of years and that f
|Contact: Margaret Allen|
Southern Methodist University