Wildflower is published quarterly by the Wildflower Center. Its content is national in scope with articles about the conservation and use of native plants as well as news from the Wildflower Center. A subscription is provided to Wildflower Center members as a benefit of membership.
Story by Andrea Abel
Photography by John C. Robinson
Imagine a 2,000-mile car trip from Florida’s tropical forests to Canada’s northern boreal forests. Now imagine making that same ecosystem journey in just 13 miles. That is similar to the experience of visiting El Cielo Biosphere Reserve south of the Tropic of Cancer in the northern Mexican state of Tamaulipas.
A botanical and avian paradise spread over 357,140 acres on a tendril of the Sierra Madre Oriental, the reserve contains at least eight distinct ecosystems with elevations ranging from about 650 feet to over 7,200 feet. Humid breezes from the Gulf of Mexico sweep up onto El Cielo’s east side and become cooler as they gain altitude. This rare combination of altitude and moisture produces what is said to be the northernmost reach of cloud forest in the Western Hemisphere.
El Cielo is home to 743 species of vascular plants as well as 460 resident and migratory bird species and other animals. As a place where plants from throughout the Americas seem to meet, the biosphere is home to northern plant species that might be found in Eastern U.S. forests, southern species from Central and South America, and nearly everything in between.
Cloud forests – found in Asia, Africa and the Americas – contain a wealth of biodiversity. More than 20 percent of its cloud forest plant and animal species are considered endemic to El Cielo, and scientists catalog new discoveries each year. Its dry-season ability to capture moisture from clouds and an abundance of natural springs make it an important year-round freshwater resource. Yet cloud forest habitats worldwide have been severely reduced due to agricultural practices, development and other economic activities.
For the uninitiated, this unlikely mix of flora in El Cielo creates visual cognitive dissonance. Bromeliads hug the trunks of enormous pine and oak trees. Plants suitable for hot, dry Texas summers like lantana (Lantana urticoides) and Turkscap (Malvaviscus arboreus) dot the landscape next to tropic-loving orchids nestled in rock and tree crevasses and pimientilla trees (Myrcianthes fragrans) that boast papery red bark which keeps epiphytes from taking hold.
The rainy season falls roughly from the end of May to mid-October, when mornings are clear and cool in the higher altitudes with early morning low fog. Clouds roll in by afternoon or evening, followed by rain and thunderstorms.
When weather patterns shift from the gulf to a continental system, the six-month dry season begins. “What saves the vegetation is that the clouds will still bank up with that little bit of moisture from the Gulf so that you will get that daily condensation of clouds. That condensation occurs on every surface. The forest can be dripping but there will be no precipitation,” says Larry Lof, director of the Field Station Program and professor of biology at The University of Texas at Brownsville. Average annual precipitation from rain and fog is about 120 inches, Lof notes.
Historically, El Cielo’s human population has been sparse. Apart from the main town of Gómez Farias, present population in the reserve is limited to a handful of ejidos, collective-type communities where people make their living with subsistence farming, livestock and tourism.
In the 1940s, access to the nearby Pan American Highway allowed increased logging. The highway also provided access for the first U.S. and Mexican researchers who began to explore the forests.
Forest fires in 1970 and 1971, combined with logging, caused near destruction to the ecosystem. At about the same time, a group of Mexican and American researchers and conservationists recognized the need to conserve this precious resource. UT-Brownsville, formerly Texas Southmost College, has had a long relationship with El Cielo beginning in the early 1960s, when faculty member Barbara Warburton began to bring student research groups to the reserve. The university still maintains a research station within the reserve and supports locally driven scientific and community development.
Various attempts were made to conserve habitat over the years, but it became apparent that a concerted and coordinated effort was necessary to ensure the protection and sustainability of El Cielo. Through the work of state officials and many other individuals and organizations, the State of Tamaulipas designated El Cielo as a biosphere reserve in 1985. The following year the United Nations Educational, Scientific and Cultural Organization entered El Cielo into its Man and the Biosphere Programme, a status that allowed for ecological conservation while maintaining a sustainable human economic presence. A new state environmental agency now holds legal and administrative purview over El Cielo. In addition, the Autonomous University of Tamaulipas (UAT) works with the state, conducting scientific research and community development projects in the reserve, explains UAT Research Biologist and Professor Claudia Gonzalez Romo.
Gonzalez and Lof describe the reserve’s dynamic ecosystems beginning with the dry thorn scrub that dominates the Tamaulipan lowlands. Crossing south over the Tropic of Cancer, the last finger of tropical forest appears in sudden steep valleys, says Lof. Prominent plants include Aphananthe monoica, known locally as ramon, and Guazuma ulmifolia or aquiche, says Gonzalez.
Turning west off Highway 85, part of the original Pan American Highway, a steady upward climb leads to the reserve; the vegetation becomes a thicket of green punctuated by brightly colored flowering shrubs in the lowlands. The town of Gómez Farias, about nine miles from Highway 85, is the hub for touristic development, local government and commerce. Most visitors use Gómez Farias as their launching point for trips into the cloud forest.
Tropical deciduous forest surrounds Gómez Farias, along with tall mango trees and fields of nopales and corn dotting hillsides. Key plants include chaca (Bursera simaruba) and juanjilón (Pseudobombax ellipticum). Rising sharply upward across a dense green valley stand the mountains leading to cooler climes and the tiny towns of Alta Cima, San José and the remote outpost of Joya de Manantiales.
Although there has been a recent rise in violence along the U.S.-Mexico border, secluded Gómez Farias and El Cielo have been very peaceful. Most visitors travel to the heart of El Cielo via pick-up trucks or personal four-wheel-drive vehicles. Not impossible but not for the faint of heart, the journey is best when it combines driving and walking to get close-up views of flora and fauna along the way.
In the lower edge of cloud forest in a valley surrounded by densely vegetated rocky outcroppings called Alta Cima, the typical plants of the cloud forest thrive, Gonzalez says, between 2,600 and 5,000 feet: oaks (Quercus germana and Quercus xalapensis), beech (Fagus mexicana), magnolia (Magnolia tamaulipana), walnut (Juglans mexicana), and an evergreen with cascading white flowers known locally as pomarrosa (Clethra pringlei) stand side by side with capulincillo (Eugenia capuli), the evergreen moquito (Podocarpus reichei) found in South America and North American eastern forest species hornbeam (Carpinus caroliniana), redbud (Cercis canadensis var. mexicana) and sweet gum (Liquidambar styraciflua).
A few miles past Alta Cima, San José is in the transition zone between hardwood cloud forest and the humid pine-oak forest that exists from about 4,500 to 6,200 feet and is characterized by Pinus teocote, P. montezumae, Quercus castanea, Q. affinis and Q. rhysophylla, says Gonzalez.
“Farther west…the moisture is all leeched out to first humid pine-oak and then dry pine-oak forest at higher elevations,” says Lof. The village of Joya de Manantiales is in this zone between 3,000 and 6,000 feet. The western slopes, deprived of the gulf moisture, descend into dry chapparal. Lof marvels at the abruptly changing microclimates: “All of that happens within a transect of maybe about 20 miles, and most of it happens in about six to eight miles.”
Dazzling, seductive orchids feature prominently in the landscape. Of the 1,200 species of orchids found in Mexico, El Cielo is home to at least 74 known orchid species, according to Jean Louis Lacaille Muzquiz, a representative of the Mexican non-profit Pro Biosfera, whose mission is to create sustainability in El Cielo Biosphere Reserve. He works tirelessly for the protection of the reserve’s flora, fauna and archaeological and historical fea tures, as well as to improve the health and livelihoods of people living in the reserve.
Through extensive research, Lacaille has documented epiphytic (growing on trees without causing harm), lithophytic (growing in rocks) and terrestrial orchid species in the reserve. “Contrary to what one might think, it is not in very wet lowland tropical forests where most orchids exist but in rainy or foggy montane forests,” explains Lacaille in a study on the orchids of El Cielo. Spring and fall are peak seasons for blooms, and several other showy species bloom during the summer months.
The orquidea monje or monk orchid (Catasetum integerrimum), named for its appearance like a hooded robe, has a waxy green flower, lives in the subdeciduous tropical forest below the cloud forest at and below about 3,000 feet, and blooms during the rainy season. Blossoms are unisexual, being one of the very few species of orchids that produces male or female flowers rather than the hermaphroditic flowers made by most orchids and other plants. “The male flowers are visited exclusively by a type of bumblebee that activates a trigger-like mechanism of the flower that shoots the pollen onto the pollinator insect,” Lacaille explains.
Lacaille notes that the orchid species found in the reserve – Laelia speciosa, Stanhopea tigrina and Prosthechea mariae – are important due to their status under Mexico’s endangered species laws. Found in the cloud forest during the rainy season, calavera or torito (Stanhopea tigrina) is considered the largest and most spectacular orchid in El Cielo. The dark-red and creamy-white blooms can be up to 6 inches across and emit a musky-sweet aroma.
At least two El Cielo orchid species – Isochilus unilateralis and Prosthechea mariae – are endemic to a relatively small area of the Sierra Madre Oriental, according to Lacaille, making protected areas and refuges all the more important for endemic or threatened species.
Lacaille says that unfortunately a strong threat right now is orchid poaching by visitors who hide plants from guides or local authorities, despite the reserve’s prohibition of any type of plant or animal collection, hunting or disturbing any part of the reserve. “Besides, native orchids are adapted to live in certain ecosystems with very particular climatic conditions. Most of these plants die when removed from their natural environment,” he says.
Although El Cielo has biosphere reserve status, it lacks many of the resources and infrastructure often associated with a protected area. While the state of Tamaulipas is building an interpretive center, there are no formal entry fees, rangers, maps, trail markers or road maintenance. Moreover, limited resources leave the reserve lacking in implementation of a management plan. According to Jorge Uribe with The Nature Conservancy’s Sierra Madre Program in Mexico (TNC), such a plan should include a public-use program that regulates and puts in order tourism and wildlife activities and also brings support to local communities under a sustainable vision.
In 2008, TNC – along with local stakeholders, academics, civil society and governmental representatives – met for three days in Gómez Farias to begin work on a conservation plan they hope to finish by the end of 2009. For El Cielo’s long-term sustainability, Uribe says ideally various zones would be designated: strategic core zones in several areas dedicated solely to conservation, tourism zones, wildlife conservation zones and areas where local communities can continue developing sustainable activities.
There remain more threats, however, than a management plan can address: climate change, fire management and invasive species, environmental education and unregulated use of all-terrain vehicles.
In many ways, it is the rough terrain and remoteness of El Cielo that may have protected it all these years from over-exploitation. “The roughness and inaccessibility protect the area, especially since they’ve ceased logging,” says Wildflower Center horticulturalist Phillip Schulze, who spent a week in the reserve. However, until a management plan and accompanying resources come into place, increased unregulated tourism is taking its toll. Once again, the strikingly rare El Cielo finds itself at a crossroads.