Miami Rock Ridge

The Miami Rock Ridge is an oolitic, continuous outcrop of limestone, part of the Miami Formation, which formerly covered a large extent of southernmost South Florida; as part of an ecosystem it formed portions of the Everglades. Rising 7 to 8.6 m (23 to 28 ft) above sea level, it ranges from northern Miami-Dade County—the approximate latitude of North Miami Beach—southward to the upper Florida Keys and southwestward into Everglades National Park, creating a karst-dominated landscape.^[1] The ridge is of Late Pleistocene origin. A series of tidal channels, dubbed transverse glades, formed within valleys in the ridge and acted as outlets for freshwater from the Everglades, thereby modifying the estuarine environment of Biscayne Bay.^[2][a] One of the few areas above pre-drainage sea level, the Miami Rock Ridge was heavily exploited for agriculture and real estate.^[5][6]

Rock outcrop closeup

Ecology

The coastal ridge was traditionally a component of the endangered pine rocklands, which grew upon its length.^[7] Globally imperiled today, the environmental community consisted of a large, unbroken expanse of South Florida slash pines (Pinus elliottii var. densa), interspersed by tropical hardwood hammocks; related to the Bahamian pineyards, it also occupied the Florida Keys.^[8][7] The communities of the Miami Rock Ridge are sustained by wildfires, including those caused by lightning strikes, which affect the vegetation and its associates, maintaining biodiversity,^[9][10] with a 20% floristic endemism rate.^[7] Climate and an often-marly substrate limit the growth of vegetation, such that a mature subtropical hammock on the ridge typically is no taller than 59 feet (18 m).^[11][12] Development has largely removed the original communities, which have fragmented into tiny parts of their original range;^[7] remnants include Vizcaya Museum and Gardens, Simpson Park Hammock, and Alice Wainwright Park, which form part of Brickell Hammock, underlain by a large oolite outcrop, Silver Bluff.^[13][14][b]

Gallery

• 
  Miami Rock Ridge at Alice Wainwright Park
• 
  View of Biscayne Bay and Key Biscayne from atop the ridge
• 
  General view of ridge from below

See also

• Arch Creek, Florida – Site of a natural arch in the Miami Rock Ridge

Notes

1. One of these glades enclosed the Miami River, a section of which sported a 6-foot-2+1⁄2-inch (1.892 m) waterfall and 450-foot-long (140 m) rapids until 1908, when it was progressively bypassed by the Miami Canal and partly dredged.^[3][4]
2. Noted first by Bernard Romans in 1771, the bluff faced Biscayne Bay as a landmark; a freshwater spring, the Punch Bowl, once gushed nearby.^[13][14]