Magdalena Valley montane forest
The Magdalena Valley montane forest is a distinctive and biodiverse biome located in northern Colombia, nestled between the central and western cordilleras of the Andes. Spanning approximately 3,628 square miles (9,397 square kilometers), this region varies in elevation from sea level to about 8,858 feet (2,700 meters). It serves as a vital ecological corridor connecting the Amazon rainforest to Caribbean ecosystems, featuring a mix of tropical dry and montane forests, marshes, and tropical rainforests. The area is recognized for its rich biodiversity, including many endemic species, such as the critically endangered blue-billed curassow and the brown spider monkey.
Despite its ecological significance, the Magdalena Valley montane forest faces numerous threats, including deforestation from cocoa cultivation, mining activities, and social conflicts. These challenges hinder conservation efforts; however, initiatives are underway to establish protected areas to safeguard the region’s unique flora and fauna. The climate is characterized by diverse weather patterns, with distinct dry and rainy seasons that vary across different elevations. The complex hydrography of the region, featuring the Cauca and Magdalena rivers, supports a variety of aquatic and terrestrial species. Overall, the Magdalena Valley montane forest is a critical area for conservation efforts, emphasizing the importance of preserving its unique ecosystems for future generations.
Magdalena Valley montane forest
- Category: Forest Biomes.
- Geographic Location: South America.
- Summary: The Magdalena Valley montane forest is one of the most unique and underprotected biomes in Colombia.
The Magdalena Valley Montane Forest biome is located along the northern foothills of Colombia adjacent to the central and western cordilleras. This independent mountain range of the Andes has an extension of 3,628 square miles (9,397 square kilometers), with limits at the Caribbean floodplains in the north, the Magdalena River in the west, the Cauca River in the east—these two being the most important rivers in Colombia—and with the central cordillera in the south. Its elevation ranges from sea level to 8,858 feet (2,700 meters), from the flooding areas of the Cauca and Magdalena rivers and the Mompox depression, to the highest peak, La Teta. The biome includes various types of habitats, from tropical dry and montane forests to large marshes and tropical rainforest. The region is a connector between the Amazon forests and the Caribbean forests and savannas.
The region retains extensive natural forests totaling 2,316 square miles (600,000 hectares), all considered native unique forests, especially the area known as the San Lucas orobioma, or elevation-oriented biome. Located in the highlands of the valley, the San Lucas is now listed in the national protected areas system. A priority region for conservation projects, it hosts many flora and fauna considered endemic (found nowhere else). Another related strategic ecosystem type occurs in the lowlands of the montane forest; these comprise the dry and wet heliobiomas, or sunlight-oriented biomes, of the Colombian Caribbean, characterized by warmer temperatures than the upland sections.
The climate in the Magdalena Valley is known as Serrania de San Lucas (SdSL), and includes three different weather patterns: dry warm, warm humid, and warm very humid. Each one has a dry season between December and March and a rainy season between April and November in the northern part of the region. The rainy season in the central and southern portions is a little longer, usually lasting into April. In the lowlands of the SdSL, the average temperature exceeds 75.2 degrees F (24 degrees C), with an average rainfall of 59 inches (1,500 millimeters). Temperatures in the highlands fluctuate in the range of 64.4–75.2 degrees F (18–24 degrees C), with average rainfall of 78–157 inches (2,000–4,000 millimeters).
The hydrography of the area is complex. In the southwestern zones, the Cauca River—one of the largest bodies of water in the country—flows north to empty into the Magdalena River. This union generates a complex series of wetlands and lagoons present most of the year, forming the Mompox depression, as the Magdalena continues flowing north. This river receives all the small tributaries that come from the SdSL and the drainage forms several micro-watersheds that connect the entire system. The eastern slope of the SdSL is covered by the Magdalena River basin, which runs across most of the country and empties into the Caribbean Sea.
Biodiversity
The Magdalena Valley Montane Forest biome is considered an endemic species center that includes the largest populations of the critically endangered and endemic blue-billet curassow, known as the Paujil (Crax alberti); the chestnut-bellied hummingbird (Amazilia castaneiventeris); and the brown spider monkey (Ateles hybridus brunneus), one of the rarest primates on Earth. Large species of vertebrates in the biome include vulnerable species such as the puma (Puma concolor), spectacled bear (Tremarctos ornatus), and Colombian tapir (Tapirus terrestris colombianus), as well as the jaguar. At least 128 fish species reside in this region, as well as 42 species of amphibians and reptiles, 478 types of birds, and 212 different mammals.
The floristic composition of these montane forests is poorly described; there are no complete inventories for the area. The only available information was gathered from 1970 to 2009 in the rapid ecological surveys by the environmental authority of the area, resulting in 240 species of plants having been reported. Among the known endemic species are Steriphoma colombiana, Amaria petiolata, Pithecellobium bogotense, and in the transition forests between dry and moist regions, the national flower of Colombia, the highly endangered Cattleya trianaei, also called the May Flower or the Christmas Orchid.
The area also has thorny vegetation, including several cacti, such as Opuntia spp., Melocactus spp., Armathocereus humilis, Stenocereus griseus, Acanthocereus pentagonus, and Pilosocereus colombianus. There are woody species of bushes and trees such as Pithecellobium bogotense, Capparis odoratissima, Bulnesia carrapo, old fustic or Dyer’s mulberry (Maclura tinctoria), and Fagara pterota. Prakinsonia aculeta, a perennial flowering tree in the pea family, Prosopis juliflora, and needle bush (Acacia farnesiana) are also found here.
Approximately 1,100 species of the area’s known flora and fauna are reported from isolated forests of the Cordillera of the Andes, dispersed throughout the entire mountain range. Of those, 509 species are considered threatened; there are five species of fish identified as vulnerable, threatened, or endangered. They are: categories of ray-finned fish (Ichthyoelephas longirostris, Salminus affinis, Brycon labiatus), tropical freshwater fish (Prochilodus magdalenae), and long-whiskered catfish (Pseudoplatystoma fasciatum).
There are three endemic bird species of the biome: the Colombian tinamou (Crypturellus columbianus), which is endangered; beautiful woodpecker (Melanerpes pulche); and sooty ant tanager (Habia gutturalis). Another six species are known as restricted-distribution birds. They are the northern screamer (Chauna chavarria), red-billed emerald (Chlorostilbon Gibson), white-whiskered spinetail (Synallaxis candei), yellow-browed shrike-vireo (Vireolanius eximius), white-shouldered tanager (Heterospingus xanthopygiu), and golden-winged warbler (Vermivora chrysoptera).
Among mammals, the biome includes eight threatened species: giant anteater (Myrmecophaga tridactyla), common woolly monkey (Lagothrix lagothricha), brown spider monkey, gray-bellied night monkey (Aotus lemurinus), white-footed tamarin (Saguinus leucopus), jaguar (Panthera onca), speckled bear, and South American tapir (Tapirus terrestris). Some global initiatives consider this biome a critical corridor for large, charismatic or umbrella species migrating in from Central America.
Environmental Protections
The Magdalena Valley montane forests are to some degree protected by a Colombian forest reserve law, Act 2 of 1959, which was created to protect soils, water, and wildlife from the main developmental processes. This category was designated for five vast ecoregions in the country belonging to the Magdalena River Forest Reserve. The large territories included in the category, coupled with expanding colonies and agricultural borders as the economy and social network evolved, quickly became obsolete and poorly enforced.
In 1999, the government created the first Rural Reserve, which provided for a more sustainable land use program, allowing livestock farming communities and agricultural activities in the forest reserve. Currently—because these ecosystems are not represented in the national protected areas systems—the Colombian government, supported by international agencies and national nongovernmental organizations (NGOs), is working to establish a national park in the region to preserve this unique ecosystem for the long term.
Some of the major problems threatening the biome include industrialized production of cocoa (Erythroxilum coca), mining, social conflict, and resource overexploitation. Cocoa cultivation results in soil erosion and homogenization of the landscape, and it pollutes the rivers and creeks with runoff from the chemicals used in its processing. Mining activities have led to high rates of natural forests loss through deforestation and elevated pollution levels resulting from cyanide and mercury additives used in mining extraction.
The introduction of heavy machinery for soil removal also increases sediment in the rivers, which is seriously affecting the fauna. All these processes are aggravated by increased illegal activities by armed groups that threaten the safety and normal development of the region, and create a complex social situation that disrupts human activities and nature conservation. Overexploitation and illegal traffic of species have significantly affected the ecosystem, seriously reducing populations of some endemic and endangered species. These disruptions may lead to the extinction of some local species. Regional authorities expect that the creation of a national protected area in this biome will largely reduce the environmental problems, and will aid human and nature development as well as conservation long-term. The effects of climate change on this region are still uncertain, but could stress the environment further.
Bibliography
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Herzog, Sebastian K., Rodney Martinez, Peter M. Jorgensen, and Holm Tiessen, eds. Climate Change and Biodiversity in the Tropical Andes. Sao Jose dos Campos, Brazil: Inter-American Institute for Global Change Research (IAI), and Scientific Committee on Problems of the Environment (SCOPE), 2011.
“The Magdalena Valley Montane Forests: A Biodiversity Haven Under Threat.” Latin America and Caribbean Geographic, 4 Jun. 2024, lacgeo.com/magdalena-valley-montane-forests. Accessed 19 Nov. 2024.
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"Species Spotlight: Brown-Headed Spider Monkey." Rainforest Concern, 10 Mar. 2021, www.rainforestconcern.org/news/species-spotlight-brown-headed-spider-monkey. Accessed 19 Nov. 2024.