Blue Mountains (Jamaica)

Rainfall

The island's average rainfall is 1,960 millimetres (77 in) per year.^{[citation needed]} Where the higher elevations of the Blue Mountains catch the rain from moisture-laden winds it exceeds 5,080 millimetres (200 in) per year^{[citation needed]} with some areas recording totals of more than 7,620 millimetres (300 in).^{[citation needed]}

Climate

High elevations of the Blue Mountains have a subtropical highland climate (Cfb) under the Köppen climate classification.

Altitudinal zonation

The biogeography of the Blue Mountains is strongly influenced by their topographic isolation and steep elevational range. The peaks rise from lowland tropical environments to approximately 2,256 metres (7,400 ft) over a short horizontal distance, creating a pronounced environmental gradient and a series of high-elevation habitats that are comparatively isolated from similar conditions elsewhere on the island.^[4]

The Blue Mountains climatic diversity has led to the growth of diverse and lush vegetation including towering trees and more than 500 species of flowering plants.^{[citation needed]} Vegetation and habitat structure change with elevation, forming broadly defined belts that include:^[5]

Elevation Zone	Climate & Terrain	Defining Flora	Key Fauna	Major Threats
Elfin Woodland (Above 1,800m)	Constant Oceanic winds; temperatures drop down to ${\displaystyle 5\,^{\circ }{\text{C}}}$.; saturated, acidic soils; continuous mist.	Short, stunted, gnarled trees (<5m); Blue Mountain Yacca (Podocarpus urbanii); thick carpets of Sphagnum moss.	Rare endemic-frogs (like Eleutherodactylus alticola); passing migrant warblers.	Severe wind damage from hurricanes; trail erosion from foot traffic.
Upper Montane (1,500m–1,800m)	Classic cloud forest; cool and damp; high canopy condensation from thick fog bands.	Tree ferns; wild ginger (Renealmia jamaicensis); rare orchids, mosses, and tank bromeliads.	Jamaican blackbird; Jamaican elaenia; the Blue Mountain Anole (Anolis reconditus).	Invasive Australian Cheesewood (Pittosporum undulatum) outcompeting native canopy trees.
Lower Montane (750m–1,500m)	Transitional climate; moderate temperatures and high rainfall; steep, draining slopes.	Broadleaf evergreen trees; Jamaican Cedar; wild figs; climbing ferns (Odontosoria).	Homerus Swallowtail Butterfly (Papilio homerus); Jamaican coney (Geocapromys brownii).	Heavy habitat fragmentation from Blue Mountain Coffee plantations and agricultural clearing.
Lowland Forest (Below 750m)	Tropical and humid; temperatures averaging 27 °C (81 °F); fast-flowing, erosive river systems.	Buttressed mahogany trees; silk cotton trees; dense networks of woody lianas.	Jamaican lizard cuckoo; Jamaican spindalis; Jamaican boa; stream-dwelling freshwater crabs.	Extensive historical logging; urban encroachment; widespread replacement by non-native fruit.

• 
  Montane Rainforest
• 
  Cloud Forest
• 
  Elfin Woodland

Endemism

This elevational structure is associated with high levels of endemism in montane plant and animal communities.^[4]

• The mountains are home to the world's second-largest butterfly and the largest in the Americas, the Homerus swallowtail. This is the most well-studied remaining population of the endangered butterfly.^[6]
• The Jamaican coney, a type of hutia and Jamaica's only native land mammal, as well as the Jamaican boa and wintering Bicknell's thrushes, are found here.^[7]
• The Jamaican Petrel (Pterodroma caribbaea). The only proven nesting was in the Blue and John Crow Mountains, where it was last seen in 1879.^[8]

High endemism in the montane zones is commonly attributed to a combination of climatic history and fine-scale geographic barriers. During cooler climatic periods, montane species could expand downslope; subsequent warming is thought to have restricted cool-adapted populations to higher elevations, increasing isolation through time.^[9]

Conservation

The mountains have been designated an Important Bird Area (IBA) by BirdLife International because they support significant populations of many Jamaican bird species.^[10]

The Critical Ecosystem Partnership Fund (CEPF) identifies the Blue and John Crow Mountains cloud forests as a critically vulnerable, high-endemism habitat characterized by a 50% plant endemism rate and specialized species, such as the Jamaican Blackbird. The ecosystem, which provides up to 40% of local water via horizontal precipitation, faces immediate threats from the invasive Australian Cheesewood tree and long-term climatic squeeze from rising temperatures.^[11]