You resist poison damage.
You have advantage on tests of Survival and Seeking in swamp terrain.
You have advantage on tests of Survival, Monster Lore, and Intrigue to know information about swamps and the creatures that live there.

You are familiar with the fens, bogs, marshes, and swamps, and the plants and creatures that live there.
The poisons favored by swamp dwelling creatures and plants are less effective on you.