Columbus day was earlier this week – and the perennial debate over whether he should be remembered as revered explorer or opportunistic exploiter was rife.  But a leading set of historians are saying that Columbus’s longest-lived legacy to the planet is actually ecological.

250 million years ago, geologic forces began to break apart the supercontinent Pangea.  Fast forward to 1492 and we find that after millennia of isolation, flora and fauna in Eurasia evolved quite differently from those found in the Americas.  Before Columbus sailed the Atlantic, only a few venturesome land creatures, mostly insects and birds, had crossed the oceans and established themselves.  Otherwise, the world was sliced into separate ecological domains largely free of invasive species and self-regulated in terms of blight and abundance. 

Some of the flora/fauna exchange post Columbus (dubbed the Columbian Exchange) was intentional; tomatoes and potatoes to Europe, oranges to the new world, and spices to and from Asia.  But others were accidental; rats, worms, parasites, and aggresive invasive species in general.  While plant and animal species have always moved around, taking advantage of certain favorable circumstances, Columbus’s fateful voyage ushered an era of globalization of the movement of flora & fauna - putting every part of the natural world in contact with every other at a staggering pace.

Categorically labelling the ecological legacy of Columbus as either negative or positive is difficult.  The global exchange of flora and fauna has resulted in vastly improved diets and industrial and personal products, but we are also dealing with its negative consequences such as the emergence of the Asian zebra mussel clogging the Great Lakes, or invasive beetles ravaging American forests.

Sipping on my glass of orange juice (originally brought to the Americas from Southeast Asia), I can’t help but think that Columbus probably had little clue as to how huge a mark he would leave on the course of global history.