Something like the Columbian Exchange is probably not a good fit for Civ-style games anyways. They are just too simple for it to evolve in a non-scripted manner, even in Colonization or something. I spent a lot of time looking into how to handle it and model colonization in the broader sense and the causes of colonization among other things for my own game. Having a much more detailed simulation *really* helps handle this stuff without abstract and gamey facades like a simpler game would have to use. Paradox games like EU4 for instance *really* blow it and Victoria 3 doesn't handle it well either.
The Columbian Exchange was by far the most comprehensive mingling of Resources known since prehistory, but by far not the only one.
Examples:
The latest issue of Scientific American has a summary of the results of a DNA study done on wine grapes, and it turns out ALL modern wine grapes originally came from the Caucasus (as we already supposed from archeological finds) but also all include enormous mingling of traits from other 'table' (food) grapes as the original wine variety spread across the Middle East, Balkans, France, northern Europe, etc. That means the 'wine grape' was never a simple movement of seeds or cuttings, but a blending process with 'native' varietals that constantly resulted in new types.
Similarly, at the end of the Neolithic there were 4 species of modern Horses in Eurasia, but selective breeding for domesticity meant that all modern horses everywhere today have the genes introduced to a single species 6000 + years ago, and all the modern varieties, from Percheron giants to 14-hand riding horses, are descended from the same originals.
Agricultural plants like Wheat, Millet, Rice, and Maize and Potato were all modified by human action, bred for better results and adaptability to human agricultural methods, so that even though 'wild' wheat already grew in Europe, the first farmers coming up from Anatolia brought their own seeds with them and cross-bred with locals to get both the cultivatability and the adaptation to local weather and soil - and this appears to have happened with nearly every plant everywhere.
So, in game terms, most 'resources' like Horses, Cattle, Sheep, Rice, Wheat, Potato, etc should be moveable or spreadable outside of their original locations - with effort.
In fact, since I believe they've claimed the game represents "10,000 years", it is starting about 4000 years earlier than Civ, around 8000 BCE. At that point, there are no horses outside of northeastern Europe to Mongolia, no domesticated/domesticatable cattle north of the Middle East and India, the British Isles are connected to Europe by land, the Sahara Desert is a savannah, and the Black Sea is about half its present size, just for starters, so the game is going to have to have mechanics for massive terrain/climate changes and associated movement of resources.
