Miami Rock Ridge

Rock outcrop closeup

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. 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. One of the few areas above pre-drainage sea level, the Miami Rock Ridge was heavily exploited for agriculture and real estate.

Long Pine Key

Map of southern Miami-Dade County showing the Miami Rock Ridge south of Miami, including Long Pine Key (in yellow)

Long Pine Key is an extension of the Miami Rock Ridge beyond the Taylor Slough. It extends about 25 kilometres (16 mi) along an east-west line, has an area of about 8,000 hectares (20,000 acres), and a maximum elevation of about 5 metres (16 ft) above sea level. It is the largest upland area in the Everglades National Park, and forms the southern rim of the Everglades basin. As with the rest of the Miami Rock Ridge, the bedrock of Long Pine Key is Miami Limestone of Pleistocene age. The rock has been subject to modification by solution and erosion, with a rough and pitted surface with caverns below. An early 20th century botanist, John Kunkel Small, stated that "... the surface consists primarily of holes."

Karst landscape

The Miami Rock Ridge hosts the Biscayne Aquifer, described as "one of the most permeable aquifers in the world". The surface of the Miami Rock Ridge is a karst landscape with sinkholes, vertical and horizontal solution pipes, sometimes open to the surface, at least one natural bridge (Arch Creek), and a number of small, shallow caves near the surface.

Transverse glades

A number of transverse glades (sometimes called "finger glades") span the Miami Rock Ridge in Miami-Dade County. Historically, the flow of water from the Everglades to Biscayne and Florida bays was through transverse glades. Some of the transverse glades completely cross the ridge, while others end on the eastern side in sinkholes. The transverse glades often fed streams and sloughs that discharged into Biscayne and Florida bays. Meeder and Harlem also describe the Shark River Slough, which flows into the lower Ten Thousand Islands on the Gulf of Mexico coast as a transverse glade.

Western parts of the transverse glades, in the margin of the Everglades basin, are broad and shallow. The central portions, on the western side of the ridge, and the eastern portions, passing through the highest part of the coastal ridge, become progressively narrower and deeper. Transverse glades in northern and central Miami-Dade County tend to follow a northwest to southeast direction, while those in southern Miami-Dade County (including on Long Pine Key) tend to follow a north to south direction. The Miami Rock Ridge is relatively close to the shore of Biscayne Bay from the north end of Miami-Dade County until some ways below the Miami River, with the transverse glades approaching the shore. Further south the ridge trends westward, with a coastal plain separating the ridge from Biscayne Bay, consequently leaving the ends of the transverse glades further from open water.

Ecology

The coastal ridge was traditionally a component of the endangered pine rocklands, which grew upon its length. 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. 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, with a 20% floristic endemism rate. 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). Development has largely removed the original communities, which have fragmented into tiny parts of their original range; 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.

See also

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.
  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.

References

Citations
  1. ↑ Multiple sources:
    • Meeder & Harlem 2019
    • "Pine Rocklands: A Disappearing Habitat". Miami-Dade Department of Environmental Resources Management. Miami-Dade County. Archived from the original on 15 May 2014. Retrieved 2019-06-11.
    • Snyder, Herndon & Robertson Jr. 1990, pp. 234–5
    • Trotta, Lauren. "Mountains of Miami". Biodiversity Institute. Gainesville, Florida: University of Florida. Retrieved 10 February 2024.
    • Trotta et al. 2018
  2. ↑ Meeder & Harlem 2019.
  3. ↑ Gaby 1993, p. 8.
  4. ↑ Lodge 2010, pp. 175, 177–9.
  5. ↑ Lodge 2010, pp. 174–80.
  6. ↑ Snyder, Herndon & Robertson Jr. 1990, pp. 271–4.
  7. ↑ Olmsted et al. 1983, p. 3.
  8. ↑ Cunningham & Florea 2009, p. 196.
  9. ↑ Olmsted et al. 1983, p. 6.
  10. ↑ Meeder & Harlem 2019, pp. 561, 563 (Figure 5), 571.
  11. ↑ Meeder & Harlem 2019, p. 562.
  12. ↑ Meeder & Harlem 2019, p. 563 (Figure 5).
  13. 1 2 3 4 "Pine Rocklands: A Disappearing Habitat". Miami-Dade Department of Environmental Resources Management. Miami-Dade County. Archived from the original on 15 May 2014. Retrieved 2019-06-11.
  14. ↑ Sullivan, Janet (1994). "Kuchler Type: Subtropical Pine Forest". United States Forest Service. Archived from the original on 2010-01-26. Retrieved 2007-06-30.
  15. ↑ U.S. Fish and Wildlife Service. "Florida Brickell-bush (Brickellia mosieri)" (PDF). Southeast Region. Archived from the original (PDF) on October 12, 2006. Retrieved 2007-06-30.
  16. ↑ Miami-Dade County. "Pine Rocklands: Born From Fire" (PDF). Miami-Dade Department of Environmental Resources Management. Retrieved 2019-06-11.
  17. ↑ University of Florida (1999). "Tropical Hardwood Hammock". South Florida Multi-species Recovery Plan (U.S. Fish and Wildlife Service). Retrieved 2007-06-30.
  18. ↑ USFWS 1999, pp. 122, 124–7.
  19. 1 2 Gann, George; Seasholtz, Alex; Dutra, Elizabeth (2024). Ecological Restoration Plan for Historical Brickell Hammock Alice C. Wainwright Park, City of Miami, Florida (PDF). Institute for Regional Conservation (Report). Delray Beach, Florida. Retrieved 22 July 2025.
  20. 1 2 Parks 1980, pp. 41, 44.
Sources

25°44′52.962″N 80°12′20.5308″W / 25.74804500°N 80.205703000°W / 25.74804500; -80.205703000