Sierra de la Laguna pine-oak forests
Encyclopedia
The Sierra de la Laguna pine-oak forests is a subtropical coniferous forest
ecoregion, found in the Sierra de la Laguna
range at the southern tip of the Baja California Peninsula
, in the state of Baja California Sur
of Mexico
.
. The pine-oak forests have a unique and diverse flora and fauna, including 694 plant species, of which approximately 85 percent are endemic
.
The higher elevation gives the ecoregion a subtropical to temperate climate, in contrast to the dry tropical climate of the lowlands. Rainfall is higher than the lower-elevation dry forests and deserts of the peninsula, averaging 760 mm annually. Rain falls mostly in the summer, with occasional winter rains.
-oak
forests varies with elevation; oak woodland
s predominate from 800 to 1200 meters elevation, with oak-pine woodlands between 1200 and 1600 meters elevation, transitioning to pine-oak forests above 1600 meters elevation. Moss
es and lichen
s are abundant throughout.
The oak woodlands from 800 to 1200 meters elevation are warmer and drier, with evergreen oaks predominant (principally Quercus devia
; Quercus arizonica
and Quercus rugosa
have a limited distribution), along with lower trees and shrubs such as Dodonaea viscosa
, Bumelia peninsularis, and Buddleia crotonoides.
Above 1200 meters elevation, the oak woodlands transition to oak-pine forests. The only pine present is an endemic subspecies
of Mexican Pinyon
, Pinus cembroides subsp. lagunae, mixed with oaks, including Quercus devia
and Quercus tuberculata, and other broadleaf trees, including Arbutus peninsularis
and Nolina beldingi
. Lower trees and understory shrubs include Calliandra peninsularis
, Mimosa xanti
, Heterotoma aurita, Verbesina pustulata and Hypericum peninsulare
. Above 1600 meters elevation, pine predominates, mixed with oaks, and with an understory of grasses (Muhlenbergia
spp. and Festuca spp.).
Tropical and subtropical coniferous forests
Tropical and subtropical coniferous forests are a forest biome. They are located in regions of semi-humid climate at tropical and subtropical latitudes. Most tropical and subtropical coniferous forest ecoregions are found in the Nearctic and Neotropic ecozones, from Mexico to Nicaragua and on the...
ecoregion, found in the Sierra de la Laguna
Sierra de la Laguna
The Sierra de la Laguna is a mountain range on the Baja California Peninsula of Mexico. It lies at the southern end of the peninsula in the state of Baja California Sur, and is the southernmost range of the Peninsular Ranges....
range at the southern tip of the Baja California Peninsula
Baja California Peninsula
The Baja California peninsula , is a peninsula in northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California. The Peninsula extends from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south.The total area of the Baja California...
, in the state of Baja California Sur
Baja California Sur
Baja California Sur , is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Before becoming a state on October 8, 1974, the area was known as the South Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises...
of Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
.
Setting
The ecoregion encompasses an area of 1100 km² (424.7 sq mi). The pine-oak forests are found above 800 meters elevation, and are surrounded at lower elevations by the Sierra de la Laguna dry forestsSierra de la Laguna dry forests
The Sierra de la Laguna dry forests are a subtropical dry forest ecoregion of the southern Baja California Peninsula in Mexico.-Location:The dry forests cover the lower elevations of the Sierra de la Laguna, from elevation. They are surrounded at lower elevations by the San Lucan xeric scrub,...
. The pine-oak forests have a unique and diverse flora and fauna, including 694 plant species, of which approximately 85 percent are endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
.
The higher elevation gives the ecoregion a subtropical to temperate climate, in contrast to the dry tropical climate of the lowlands. Rainfall is higher than the lower-elevation dry forests and deserts of the peninsula, averaging 760 mm annually. Rain falls mostly in the summer, with occasional winter rains.
Flora
The composition of the pinePine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
-oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
forests varies with elevation; oak woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...
s predominate from 800 to 1200 meters elevation, with oak-pine woodlands between 1200 and 1600 meters elevation, transitioning to pine-oak forests above 1600 meters elevation. Moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
es and lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...
s are abundant throughout.
The oak woodlands from 800 to 1200 meters elevation are warmer and drier, with evergreen oaks predominant (principally Quercus devia
Quercus devia
Quercus devia is a species of plant in the Fagaceae family. It is endemic to Mexico. It is threatened by habitat loss.-Source:* Nixon, K. et al. 1998. . Downloaded on 23 August 2007....
; Quercus arizonica
Quercus arizonica
Quercus arizonica, the Arizona White Oak, is found dominantly in Arizona, southwest New Mexico, northeast Sonora and Chihuahua, all Madrean Sky Islands associated regions. It is a long-lived oak in the family Fagaceae, native to eastern North America...
and Quercus rugosa
Quercus rugosa
Quercus rugosa is a species of oak tree which is found in Mexico and the southwestern United States.-Source:...
have a limited distribution), along with lower trees and shrubs such as Dodonaea viscosa
Dodonaea viscosa
Dodonaea viscosa is a species of flowering plant in the soapberry family, Sapindaceae, that has a cosmopolitan distribution in tropical, subtropical and warm temperate regions of Africa, the Americas, southern Asia and Australasia.-Description:...
, Bumelia peninsularis, and Buddleia crotonoides.
Above 1200 meters elevation, the oak woodlands transition to oak-pine forests. The only pine present is an endemic subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of Mexican Pinyon
Mexican Pinyon
The Mexican Pinyon ' is a pine in the pinyon pine group, native to western North America.-Distribution:The range extends from westernmost Texas, United States , south through much of Mexico, occurring widely along the Sierra Madre Oriental and Sierra Madre Occidental ranges, and more rarely in the...
, Pinus cembroides subsp. lagunae, mixed with oaks, including Quercus devia
Quercus devia
Quercus devia is a species of plant in the Fagaceae family. It is endemic to Mexico. It is threatened by habitat loss.-Source:* Nixon, K. et al. 1998. . Downloaded on 23 August 2007....
and Quercus tuberculata, and other broadleaf trees, including Arbutus peninsularis
Arbutus
Arbutus is a genus of at least 14 species of flowering plants in the family Ericaceae, native to warm temperate regions of the Mediterranean, western Europe, and North America.-Description:...
and Nolina beldingi
Nolina
Nolina is a genus of tropical xerophytic flowering plants, with the principal distribution being in Mexico and extending into the southern United States. Some botanists have included the genus Beaucarnea in Nolina. In the APG III classification system, it is placed in the family Asparagaceae,...
. Lower trees and understory shrubs include Calliandra peninsularis
Calliandra
Calliandra is a genus of flowering plants in the pea family, Fabaceae, subfamily Mimosoideae. It contains about 200 species that are native to tropical and subtropical regions of southern Asia, Africa, Australia and the Americas.-Biological description:...
, Mimosa xanti
Mimosa
Mimosa is a genus of about 400 species of herbs and shrubs, in the subfamily Mimosoideae of the legume family Fabaceae. The generic name is derived from the Greek word μιμος , meaning "mimic."...
, Heterotoma aurita, Verbesina pustulata and Hypericum peninsulare
Hypericum
Hypericum is a genus of about 400 species of flowering plants in the family Hypericaceae ....
. Above 1600 meters elevation, pine predominates, mixed with oaks, and with an understory of grasses (Muhlenbergia
Muhlenbergia
Muhlenbergia is a genus of grass in the Poaceae family. It is named in honour of the American amateur botanist Gotthilf Heinrich Ernst Muhlenberg. There are around 155 species. Many are known by the common name muhly....
spp. and Festuca spp.).
See also
- Category: Natural history of Baja California Sur
- Conifers of MexicoConifers of MexicoMexican conifers extend mainly in the main mountain ranges: Sierra Madre Oriental, Sierra Madre Occidental and the neo-volcanic axis, enclosed between these mountains there are disperse groups of conifers in mid and high elevations valleys when rainfalls conditions allow its growth. Mexican...