Sierra de la Laguna Pine-oak Forests Habitat
This taxon is found in the Sierra de la Laguna pine-oak forest, a mountainous ecoregion which rises from the arid Baja California Sur, creating islands of unique vegetative communities. There are approximately 694 plant species, approximately 85 of which are endemic to this ecoregion. Overall species richness is low to moderate, with a total of only 231 vertebrate taxa. The ecoregion is classified in the Tropical and Subtropical Coniferous Forests biome. Much of the pine-oak association remains intact due to the inaccessibility of the rugged and inaccessible terrain.
The topographical features and geological events that gave rise to this particular region are responsible for the diversity of climates and vegetation in the same area. The highest strata of mountains, situated at 1600 to 2000 metres (m) in elevation, are composed of pine-oak forests that transform into oak-pine forests (1200 m) and oak forests (800 m) as elevation decreases. The climate is temperate sub-humid with summer rains and occasional winter rains.
These pine-oak forests constitute the wettest portions in the state of Baja California Sur (760 millimetres of precipitation annually). Slight variations in climatic conditions make up three different vegetation assemblages in the temperate forest. Pine forests at the highest elevations are dominated by Pinus cembroides ssp. lagunae, and understory taxa such as Muhlenbergia spp. and Festuca spp. Pine-oak forests dominated by associations of Pinus cembroides subsp. lagunae with Quercus devia, Arbutus peninsularis, and Quercus tuberculata, and a variety of trees of smaller stature such as Calliandra peninsularis and Mimosa tricephala, with associated shrubs to complement the landscape.
Some of the endemic reptiles are the Southern Alligator Lizard (Elgaria multicarinata) and the Yucca Night Lizard (Xantusia vigilis). Other reptilian taxa found in the Sierra de la Laguna pine-oak forests include the Baja California Rock Lizard (Petrosaurus thalassinus), Baja California Rattlesnake (Crotalus enyo) and the Baja California Brush Lizard (Urosaurus nigricaudus).
Only two amphibian taxa are found in the Sierra de la Laguna pine-oak forests. The Red-spotted Toad (Anaxyrus punctatus) is one anuran found here. The widely distributed California Chorus Frog (Pseudacris cadaverina) is another resident of the ecoregion. One other anuran, Pseudacris regilla, was previously recognized in the ecoregion, but erecent DNA analysis has rendered this taxon of unclear distribution.
Of the approximately 30 mammalian species of mammals present, one of them (an endemic bat) lives only in pine-oak forests. The level of endemism is high, and this is well demonstrated by the proportion of endemic species with respect to total recorded species. More than ten percent of the mammalian species found at Sierra de la Laguna are endemic. One notable mammal found along the far west coast, including California and Baja, is the Ornate Shrew (Sorex ornatus). There are several threatened mammals found in the Sierra de la Laguna pine-oak forests, including: the Mexican Long-tongued Bat (Choeronycteris mexicana NT). The isolation of this region has contributed to the scarcity of predators, and to the poor competitive ability of some animals. Rodents and lagomorphs are virtually absent from the region
The avifauna inhabiting these pine-oak forests is important because half of the bird species breeding at Sierra de la Laguna only utilize pine-oak forests as breeding habitat. The endemic Baja Pygmy Owl (Glaucidium gnoma hoskinsii), along with the White-winged Dove (Zenaida asiatica) and Golden Eagle (Aquila chrysaetos) are only a few of the avian species found in this ecoregion. Other notable birds in this and the Gulf of California xeric scrub ecoregion include the Xantus's Hummingbird (Hylocharis xantusii) and the endangered Peninsular Yellowthroat (Geothlypis beldingi EN)..
- A. Ortega and L. Arriaga. 1988. Consideraciones finales. Pages 229-237 in L. Arriaga, and A. Ortega, editors, La Sierra de la Laguna de Baja California Sur. Centro de Investigaciones Biológicas de Baja California Sur, México.
- C. Michael Hogan & World Wildlife Fund. 2013."Sierra de la Laguna pine-oak forests". Encyclopedia of Earth, National Council for Science and the Environment, Washington DC ed.Mark McGinley.