Micro-environments and micro-climates are niche environments that develop due to unique conditions. The use of a niche in reference to democracy acts in the same manner. Democracy requires a very unique set of nutrients to thrive.
Violence, inequity, slavery, misogyny, and selfishness are some of the ingredients in the manure out of which the seed of democracy sprouts. But once it breaks ground and reaches the sun, the power of altruism causes it to flourish.