feral dromedaries roaming the outback, and in North America we have herds of feral horses. Are these dangerous invasives that compete with "native" species like bison and kangaroos, or are they filling niches that have been either left empty or filled by domestic cattle since the Pleistocene?
Introduced Herbivores Restore Late Pleistocene Ecological Functions.
Humans have caused extinctions of large-bodied mammalian herbivores over the past ∼100,000 y, leading to cascading changes in ecosystems. Conversely, introductions of herbivores have, in part, numerically compensated for extinction losses. However, the net outcome of the twin anthropogenic forces of extinction and introduction on herbivore assemblages has remained unknown. We found that a primary outcome of introductions has been the reintroduction of key ecological functions, making herbivore assemblages with nonnative species more similar to preextinction ones than native-only assemblages are. Our findings support calls for renewed research on introduced herbivore ecologies in light of paleoecological change and suggest that shifting focus from eradication to landscape and predator protection may have broader biodiversity benefits.So, I guess, let the hippos run free, and the camels and the ponies, so the world can be more like it was. And when we can bring back the mammoths and others, the world we then be more like the one they lived in, and they will be more likely to thrive.