Cheshire Cat Photo Blog(...said the Cat: 'we're all mad here....')

According to a joint report in PNAS (Proceedings of the National Academy of Sciences) by UC Berkeley, Stanford University, California State University Sacramento and the University of Chile, the extinction of large land animals (megafauna extinction) can have a cascade effect on local ecosystems, including those of Northern California, where many smaller animals and plants died off after mammoths were wiped out. The study looked at past extinctions in North and South America since humans arrived about 15,000 years ago. The study is relevant because of the nearness of species like elephants (my Oakland Zoo photo above) and rhinoceros to extinction. The size of elephants, wildebeest and other big plant-eaters not only makes them impressive and fascinating, but vital to the many species, including flora and fauna, that live with and depend on them. SFGate.com reports:

“Ecological studies have shown that if you pull out a top predator or a key herbivore today, you get dramatic change in the ecosystem,” said Anthony Barnosky, a UC Berkeley professor of integrative biology and the study leader. “Our study makes it clear that in the past, such changes have lasted for thousands of years. These extinctions really do permanently change the dynamics. You can’t go back.”

The scientists found that the number and diversity of small animals and vegetation decreased all along the Pacific Northwest, as well as the western and northeastern United States, after mammoth and mastodon extinctions. In Alaska and the Yukon, what was once a mix of forest and grassland became mostly tundra after the loss of mammoths, native horses and other large animals, according to the study.

Nowhere has the change been more dramatic than in the Bay Area. Columbian mammoths were among thousands of now-extinct animals that roamed the region as late as 12,000 years ago. The shoreline was 12 miles farther out at that time, and a vast plain stretched from the Golden Gate, where a fast-moving river flowed, to the Farallon Islands.

Herds of mammoths, mastodons, camels, horses, llamas, elk, tapirs, moose and bison would have darkened the Farallon Plain. Mingling with these great herbivores were predators like the short-faced bear, saber-tooth cat, wolf packs and prides of California lion.

Since that time, 60 species of large animals in North America have become extinct. The study is most relevant “…because previous studies have concluded that Earth is in the midst of a sixth mass extinction. A report published in June in the journal Science Advances found that animals are going extinct at a rate 100 times faster than they should. It concluded that humans are polluting the ecosystem, destroying habitat and killing off species at a rate so rapid that the demise of animals like elephants, tigers, rhinoceros and others could occur within three human lifetimes.”

The extinction of browsing animals like mastodons, mammoths, and elephants, as well as bison and moose alter the environment by eating small trees and shrubs, by uprooting trees and churning up soil, and by distributing seeds and changing soils nutrients when they defecate and urinate. The result of the extinctions is more open grassland, fewer forests and a different mix of both plants and animals.

“You see the impact of defaunation today in Africa, where the removal of elephant populations has led to these shrubby, scraggly acacias filling the savanna landscape,” said co-author Charles Marshall, a professor of integrative biology and director of the UC Museum of Paleontology. “Africa today, with its elephant populations, seems to fit the model of North America with its mammoths and mastodons.”

-Bill at