I did a S&R changing "rainforest" to "rain forest".
Came across one issue.
It dropped a space into my permalinks that had "rainforest" in them. On output they showed as rain%20forest, but that's not valid, it should have been rain-forest.
It seems to me permalinks ought to be escaped to use hyphens... maybe even regex to identify inline links in content and drop hyphens in there to.