This is a fantasy universe, so I can invent plants, but I don't want it to be totally unrealistic.
2. I'm trying to write a story set on a reasonably small island. The people are completely isolated from the rest of the world and have been for a long time--they aren't even sure that the rest of the world still exists. Most of the society makes their living through fishing; they have pretty primitive, stone-age technology, and very few craftsmen. They don't even have currency, I think--they barter.
What would be the smallest realistic population size?
Actually, I'm trying to find a balance between a viable population and not--I want them to be straddling the edge. (The main character, a young woman, is one of the only ones her age, I think.) If it's necessary, to explain why the population is smaller than it was a few generations ago when it was definitely viable, there could have been an epidemic or a disaster like a flood.