Growing Concern

With Monaco and Macau sporting large population densities that allow little room for growth - edible plant growth, that is - and Djibouti's 21 people per square kilometre turning into 51,861 when applying the real population density measure, what nations are best placed for self-sufficiency? By the look of it, it's another five that have all received recent mention: Niger (84), Canada (78), Niue (72), Kazakhstan (69) and Australia (43).