Nomadic Resilience

A nomadic life in the wilds has toughened you and left you accustomed to harsh climates and rugged terrain. You gain +1 to your Constitution score and gain an AC bonus equal to your Constitution modifier when wearing no armor. 

Additionally, when you take this feat choose a terrain type and gain the following features:

• Mountains. You gain resistance to cold damage and are unaffected by cold climates. You gain advantage on strength checks to move or clear boulders, fallen rocks and debris and advantage on saving throws to avoid falling rocks, rubble or debris. When in a mountainous environment you may ignore naturally occurring difficult terrain. You may also ignore any difficult terrain caused by rubble or other rocky debris. 
• Swamp. You gain resistance to poison damage and gain advantage on saving throws to resist poison and disease. When in a swamp, marsh, bog, etc. you may ignore naturally occurring difficult terrain. You may also wade through high water at your normal movement speed and ignore difficult terrain caused by muck, mud, etc.
• Forest. When in a wooded environment you cannot be surprised and gain advantage on  ability checks for perception, insight, survival, nature and animal handling. You may ignore any difficult terrain caused by plant growth such as roots, brambles, branches and thickets, whether natural or resulting from a spell or other effect. 
• Plains. You have advantage on ability checks for perception, insight, survival and nature when traveling through grasslands and fields, or when traveling on the open road. Additionally, when traveling in these environments, your party covers 1.5 miles for every 1 they would normally and cannot be surprised. 
• Island. You gain swim speed equal to your movement speed and can hold your breath twice as long as you normally would. You gain proficiency in navigator's tools and water vehicles. When traveling on the ocean, under sail, your party covers 1.5 miles for every 1 they normally would and cannot be surprised by enemies on or above the water. You have advantage on nature, perception or survival checks to detect creatures below the surface.