Final answer:
The island that gained independence from Australia in 1968 and whose economy was traditionally based on guano is Nauru. The guano mining industry brought great wealth to the island until the resources were depleted, leaving a devastated landscape and limited economic options.
Step-by-step explanation:
The island in question is Nauru, a small island nation that gained independence from Australia in 1968. This island, which is only about eight square miles in area, had its economy traditionally based on the mining and export of guano, a rich natural fertilizer composed of seabird droppings.
Guano was a highly sought-after commodity for its ideal concentrations of nitrogen, phosphorus, and potassium, making it an excellent fertilizer. The mining of guano and later phosphate deposits led to significant wealth for the island; however, the exhaustion of these resources left a devastated landscape and few other options for continued prosperity. Many of Nauru's residents have had to rely on investments from the mining boom or seek livelihoods elsewhere.