Survival gardening is a phrase that has been thrown about and equated with permaculture, which it is not. Permaculture is lasting plantings of perennials which give abundantly year after year, while survival gardening is active gardening with a care to provide all of a person's nutritional needs.
All nutritional needs. Fats, carbohydrates, proteins, fibers, trace minerals, and vitamins.
There is a lot of debate as to how much land it would take to provide for all nutritional needs. Some people might say one acre per person, others more. Would all nutritional needs include meat and fish? what about the healthy fats that are in avocado and olives? So everyone is going to have their own opinion on land consumption, particularly in regards to climate and use, for example, like bio-intensive agriculture.
I think as far as growing protein the first thing that jumps to mind is nut trees, and the first one that really jumps to mind is pecans. They grow really well in most parts of Florida, where other nuts fail. The rumors of a pecan blight exist, though I have not seen it for myself yet. Then there are bean plants, which are low-growing, sun-loving herbaceous protein factories. Peanuts, cowpeas, and green beans all do well here. Probably the best part about growing beans is that the plant stalk and leaves make great fodder for livestock once the beans are harvested. Sprouted grains are reputedly high in protein and vitamins.