Montane Evergreen Forest
Mature and largely unspoiled Montane Evergreen Forest in southeastern Peru. Photo: Fernando Angulo.
Definition: Montane Evergreen Forests are wet to very wet forests generally found in mountains beginning at elevations of 1500 m. Trees are regularly 25-30 m (82-98 feet) tall with relatively small and rounded crowns. The trunk and branches are twisted and covered in moss and bromeliads.
Where does the Montane Evergreen Forest start?
While is generally thought that Montane Evergreen forests start at approximately 1500 m of elevation, this actually varies and it is often influenced by the local geography. The point where Montane Evergreen Forest begins has more to do with the altitude at which clouds over the tropical lowland evergreen forest hit the mountain forest. This point is marked by the sudden presence of moss and epiphyte plants as the constant shrouding of the clouds provides a constant supply of water.
The upper limit of montane forests is the timberline with a transition of shrubs and grasses before the high altitude grasslands.
The point where the ascending clouds from the lowlands hit the towering Andes generally marks the beginning of the Montane Evergreen Forest.
The beginning of the Montane Evergreen Forest is marked by the noticeable presence of moss, bromeliads, and other epiphytes. This point is generally located between 1200 to 1500 meters of altitude but could vary locally. Photo: Diego Calderon.
Overall, the Andean montane forests encompass temperate and montane rainforests within the tropical zone ranging from approximately 1,300 m (4,265 feet) up to c. 3,600 m (11,811 feet) of altitude. The Annual precipitation generally exceeds c. 1,000–1,200 mm, and ground level clouds are frequent. The mean annual temperature at the lower limit of the montane forest is about 20 C, (68 F) with a low temperature of approximately 7 C (44 F).
Diversity in the Montane Evergreen Forest
The characteristic flora in the mountains tends to strongly depend on elevation, because of the changes in climate. As elevation increases, the climate becomes cooler. This changes in temperature and climatic conditions cause life zones or bands of similar ecosystems at similar altitudes. Varying ecosystems at different altitudes result in many species of animals and plants occupying within narrow elevational ranges.
The upper limit of the Montane evergreen forest is generally found at 3500-3650 meter of altitude. At this point, the forest gives way to shrubs and grasslands at higher elevations. Photo: Henry Gonzales.
The Andean montane forest ecoregion is among the most diverse regions on the planet. The disjunct formation of Andean mountain chains and pronounced periods of isolation of peaks and valleys forced plants and animals communities to adapt to different conditions after being cut off from each other. The process of isolation and interconnection laid the perfect foundation for speciation.
Geographic isolation and interconnection coupled with altitudinal ranges and a complex biogeographical history resulted in an altitudinal migration of vegetation zones in response to changing climates. These ecosystems today present a diverse array of distinctive biological communities, characterized by unusually high levels of endemism in plants and animals.
The Montane Evergreen Forest not only boasts the highest biodiversity, but also the highest percentage of endemic species. About 50% of its flora is found nowhere else and contains the highest concentration of endemic bird areas.
Problems Facing the Montane Evergreen Forest
Unfortunately, people have found these areas suitable for colonization and have disturbed these natural areas in many ways since pre-Colombian times. Although some reasonably sized continuous forests still exist, patchiness and fragmentation from farms and other anthropogenic influences have disturbed these highly sensitive forests.
See more Neotropical bird habitats.
- Hartshorn, G.S. 1983. Plants, In D.H. Janzen, ed., Costa Rican Natural History. Chicago: University of Chicago Press.
- Klein, Brad, Western South America: Northwest Colombia to southern Ecuador, World Wildlife Fund.
- Neotropical Birds: Ecology and Conservation. Stotz Douglas F., Fitzpatrick John W., Parker Theodore A. III, and Moskovits Debra K. University of Chicago Press, 1996.
- Terborgh, John 1992. Biodiversity and the Tropical Rainforest. Scientific American Library, New York.