"When you take a look at what could've caused this, it really does just keep pointing to humans," Steadman said. "I just think it's habitat loss from people and introduction of non-native, invasive plants and animals. It's the same thing we're dealing with in Florida now who knows what the pythons are going to wipe out in the Everglades."
Researchers radiocarbon-dated six individual bones from the extinct woodcock to determine the site's age. Because the locality also includes fossils of frogs, lizards, snakes, bats and rodents, in addition to the Common Barn Owl and Ashy-faced Owl, it was likely a roost where owls deposited boney pellets of their prey, scientists said.
Of the present-day species found at the site, as many as one-third are considered threatened today and four of the 23 total species are no longer found in the area. Their predominant habitat was pine forests, which are mostly disturbed today or entirely cut down for agriculture. The Least Pauraque, a type of nightjar, is now an endangered species that lives in an extremely localized area, Steadman said.
"This gives us some evidence of how drastic the range contraction was of this species the Least Pauraque not only lived in the mountains, it was common there," Steadman said. "Within 1,000 years, it's lost most of its range and most of its population. From the standpoint of evolution, if we want that species to ever have the opportunity to evolve through time, we need to be concerned with time intervals that are measured in centuries and millennia, not just decades."
Jim Mead, professor and chair of the department of geosciences at East Tennessee State University, said the research is important because the direct radiocarbon dating represents a much later time period than the arrival of the first Amerindians.
|Contact: David Steadman|
University of Florida