The approach to Baton Rouge moving along I-10 west from New Orleans to LSU is a long, undulating line of grey interstate propped over pilings in the bayous between the Crescent City and the state capital. Long stretches of swamp are broken up only by channels cut into the landscape, long empty lines of water stretching to the horizon. For long stretches someone has nailed signs reading "KEEP OUT" every hundred feet or so to trees along the roadside, trees that border what is absolutely nothing but water, muck, trees, snakes, and other slimy demons of the overactive and fearful imagination.
It's a hostile environment where everything gets eaten eventually. This is a metaphor.