GAINESVILLE, Fla. --- A University of Florida study demonstrates extinction's ripple effect through the animal kingdom, including how the demise of large mammals 20,000 years ago led to the disappearance of one species of cowbird.
The study shows the trickle-down effect the loss of large mammals has on other species, and researchers say it is a lesson from the past that should be remembered when making conservation, game and land-use decisions today.
"There's nothing worse for a terrestrial ecosystem than the loss of large mammals and the loss of apex predators like sharks, tuna and other large fish will have the same negative impact on the oceans," said study co-author David Steadman, ornithology curator at the Florida Museum of Natural History on the UF campus. "We're seeing it with the loss of lions and elephants in parts of Africa, as well as in Florida with the decline of panthers. There's no question these losses will have a negative domino effect on our ecosystems."
The fossil study of eight songbird species from northern Mexico by Florida Museum ornithologists is currently available online and will appear in Tuesday's print edition of the journal Palaeogeography, Palaeoclimatology, Palaeocology.
An extinct cowbird, Pandanaris convexa, is the most common bird found at the fossil site called Trapa, in Sonora, Mexico, about 150 miles south of Arizona. This is the first time fossils of the large bird, a member of the blackbird family, have been found in Mexico.
Finding the extinct cowbird at the fossil site was unpredictable and unexpected, according to Jim Mead, chair of the department of geosciences at East Tennessee State University, who has collected a variety of fossils at the site, including the birds used in the study. Mead described the findings at Trapa as "bizarre and exciting."
"The tropical environment is unusual because the site is so far from the coast," Mead said. "The fossil reco
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