This area is an artificial wetland area. It was created in theearly '90's during construction of the expanded Disney-MGM Studios parking lot. The Studios parking lot originally went as far as the big canal that cuts through the middle of the lot. Due to high demand, the parking lot was expanded, but the expansion was into an area that was designated as wetlands. In order to get approval to destroy the wetlands, Disney had to create an equal amount of wetlands somewhere else. So this area just to the west of World Drive was dug up and then planted with wetlands vegetation. The dirt that was hauled out was used to fill the other wetlands for the parking lot.
This process ended up being such a nuisance that when Disney later wanted to develop more wetlands area, instead of creating wetlands, they pproposed the first "wetlands swap" in the state of Florida. They got to develop some wetlands at WDW in exchange for preserving about 10 times as much threatened land elsewhere. Thus Disney's Wilderness Preserve near Poinciana came to be.