My players are... a little destructive. They have burned a town to the ground (slaughtering everyone in it) and just left a second town (in the same kingdom) with several buildings being lit on fire. Fictionally, and mechanically, how should I handle this? The initial town they destroyed was fictionally set up as the sole source of food and water for the entire area (they are in a desert basin). How would I mechanically show one town moving in to take over the production of food? Or the swift decline of civilization in the area because all the people are starving? Or something. I know this is a bit of a vague question, but any advice (or stories from personal experience) would be greatly appreciated!