How do you decide whether someting is native or not native? A common cutoff used by ecologists in the U.S. has always been the arrival of Columbus. The 16th century benchmark is also used in Europe, but in a slightly different way: archaeophytes are species introduced before the year 1500, neophytes are those introduced after.
Now some scientists are going even further back in time to place their benchmark. It has been 13,000 years since large predators and herbivores (mega-megafauna?) roamed North America. So long ago that it is impossible for most humans to imagine, but the scientists have determined this to be the time at which we had the right mix of species. Unfortunately, many of these species are extinct, so the proposal is to "re-wild" the continent with their African and Asian counterparts. Read a summary from Scientific American, or read the full commentary from Donlan et al. in the journal Nature.
Could introducing top-level predators like lions and cheetahs, and large herbivores like camels and tortoises, really restore the health of American ecosystems? None of you reading this will be around long enough to find out. The real questions you should be thinking about are:
- How do we determine the "health" of an ecosystem?
- How do scientists currently rate the health of ecosystems where these mega-megafauna currently live?
- What is the risk of re-wilding introducing a new pathogen that will negatively impact native species? The Nature commentary notes this is a real risk that must be evaluated before proceeding. It also notes that there are already over 75,000 large introduced mammals (most from Africa) currently residing at ranches in Texas!
- Where does this stop? Should Friends for Floyd get their way and "re-"introduce pink flamingos to Utah? Should we start reforesting land according to what species are found in pollen cores? What about the dinosaurs? When the heck are we going to start cloning dinosaurs???
P.S. - Faithful readers, you can now stop emailing me about blogging this story. I tried to ignore it, but y'all wouldn't let me :-).