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When I first came to Campeche (invited by Carlos Galindo-Leal to coordinate an ambitious research program for Stanford University, for three years) I found the state freaking hot and humid, too flat and a bit dull...I was about to say no, until I went to Calakmul. We spent a cold November night at the core of the Calakmul site, and then the magic happened...I was hooked...forever.
Many things have changed since that cold morning of November 1995 at the top of the Structure III (the highest Mayan pyramid) in the Calakmul Archaeological site, when the magical combination of the sight of “a sea of trees” (extending as far as the horizon line to 360 degrees), the sounds of the jungle (including those amazing echoes coming from countless parrots and toucans, howler monkeys and crested guans) and the sheer beauty of a day-break in one of the true last frontiers of civilization on earth, hook me forever to the thrills and frustrations of tropical ecological research in the southern Yucatan peninsula of Mexico.
With humans living throughout most of the terrestrial world, conservationists have sought varying solutions to protect remaining biodiversity. One possible solution proposed by the United Nations Educational, Scientific, and Cultural Organization (UNESCO) was the concept of Biosphere Reserve, a protected area that incorporates biodiversity conservation, economic development, and research and monitoring associated with the first two functions. The network of Biosphere Reserves include hundreds of protected areas in the countries that harbours most of the biological diversity, including Mexico. In the south eastern portion of the Yucatan Peninsula “Calakmul” was designated as a protected area by the Mexican government in 1989 and was named a biosphere reserve in 1993.
Decreed by presidential mandate in 1989 with the highest protection status available in Mexico, the 1,786,267 acre (723,185 ha) Calakmul Biosphere Reserve is the largest protected area of tropical forest in Mexico and one of the largest in the whole of Mesoamerica. The site is situated in the new Ecological Municipality of Calakmul in the southern state of Campeche. Calakmul is part of the Mesoamerican Corridor which stretches from northern Quintana Roo to the tropical forests of Peten in Guatemala and Montes Azules in Chiapas. It protects numerous archeological sites from the great Maya culture, which reached its peak in the late classic period.
Archaeological centres such as Balamku, Hormiguero, Chicanna, Río Bec and Calakmul stand as testimonies of the area’s rich cultural heritage. In 1993 Calakmul was designated a UNESCO Man and the Biosphere site. Today, most people refer to the Calakmul region (including the Calakmul municipality, biosphere reserve, buffer and corridor areas around it) as the Greater Calakmul Region (GCR) and this name will therefore be used in this document when making reference to this eco-geographical region.
The GCR and the reserve it include are important elements in a larger system of protected areas which form an ecological corridor of over two million hectares stretching between central Yucatan and the Belizean forests. The main objective of the Calakmul Biosphere Reserve is the long-term maintenance of biodiversity. Accepted into the UNESCO network of biosphere reserves in 1993, the Calakmul Biosphere Reserve is divided into core and buffer zones. Although to date no management plan has been implemented, the general understanding is that ecologically-sustainable production activities are allowed within the buffer zone while no human activity is permitted within the core zone. Conflict arises from the fact that the borders of the core zone cut across the territory of pre-existing ejido communities (an ejido is a land grant administered by a group of individuals called ejidatarios who hold the usufruct rights to their land or ejido) accorded to them by the Mexican federal government and privately held properties. Agriculture, forestry, cattle-ranching and subsistence-level hunting are practised on ejido and privately held lands that overlap with the reserve.
The Calakmul Biosphere Reserve encompasses slightly more than 723,000 ha but the whole of the GCR probably reaches around 1 million ha when all the forested private and communal (ejido) lands are considered. Comprising the largest protected tract of tropical forest remaining in Mexico, Calakmul is one component of the Maya Forest, a large expanse of tropical forest extending over several states in Mexico, western Belize, and northern Guatemala that in total sums up for more than 2.5 million hectares; that is the largest continuous tropical forest north of the Amazon.
With its large tracts of tropical forests, the GCR possesses great natural and cultural assets. A mix of old growth, medium semi-evergreen and seasonally inundated lowland forests, as well as grasslands, makes the site a refuge for a great variety of animal species, including threatened species such as jaguar (Panthera onca), puma (Puma concolor), tapir (Tapirus bairdii), black howler monkey (Alouatta pigra), Central American spider monkey (Ateles geoffroyi), anteater (Tamandua mexicana), ocellated turkey (Agriocharis ocellata), great curassow (Crax rubra), keel-billed toucan (Ramphastos sulfuratus), king vulture (Sarcoramphus papa), and many more. This tropical forest, together with the rest of the Mesoamerican Corridor, allows for the movement of species from the Yucatan province (sub-xeric) to the Peten isthmus (subhumid and humid) and is also an important wintering ground for several migratory bird species. Thirty percent of the bird species sighted in the reserve breed in the United States and Canada and use these forests as their wintering grounds. Some of these neotropical migrants such as the hooded warbler (Wilsonia citrina) and the Swainson’s warbler (Limnothlypis swainsonii), are threatened or endangered species.
The site is unique with regards to the number of rare, endemic, species in danger of extinction and special protection species in Mexico; including six of seven species of marsupials, two of three primates, two of four edentates, and five of six species of felines; jabiru stork, king vulture, elegant eagle, three species of toucans, several species of parrots, Moreletti crocodile, Ctenosaura iguana, Claudius tortoise and the endemic and extremely rare Triprion petasatus tree frog. Flora of the site includes the only Canellasea family on the American continent, six endemic genre, five threatened species, two rare species, and 380 endemic species among the more than 420 species of trees described so far the GCR represents the last stronghold for the conservation of pure stands of Guayacan (Guayacum sanctum) forests in the world.
At the beginning of the colonial period approximately 20,000 Mayans lived in GCR dense forests, practising traditional agriculture and hunting activities. In the early 20th century the extraction of chicle (the natural resin obtained from zapote trees to produce chewing gum) and wood became important in the region, new roads were built and many small scattered human settlements established in the area. At present approximately 23,700 people from 23 different states live in 72 settlements, most of them located on the eastern side of the reserve. The main economic activities in the area are timber extraction, commercial and self-sustenance agriculture, ranching, honey production, subsistence hunting, tourism and small-scale commerce.
The buffer zone of the southern division of the reserve is composed of forest extension lands belonging to ejido communities north of the reserve. The Calakmul Biosphere Reserve is a patchwork of mature disturbed forest, secondary growth vegetation of less than 25 years and savanna-type flood plains. The present state of the forest both within the reserve and in the ejido communities that surround it is a result of timber extraction, forest clearing for agriculture and cattle ranching. The most abundant tall trees include chicozapote (Manilkara zapota) and ramón (Brosimum alicastrum). Prominent commercial species are mahogany (Swietenia macrophylla) and Spanish cedar (Cedrela odorata). Biological inventories indicate that 18 endemic plant species are found in the larger Peten ecosystem
Despite its geographic isolation, the reserve and its immediate surroundings experienced considerable population growth during the 1980s and 1990s, placing increasing pressure on resources in the region in general and on the biosphere reserve in particular. Results of the socio-economic studies in the region indicate that rapid population growth continued in the region through the 1990s, affecting most localities in or near Calakmul, in large part due to continued migration (likely) from other parts of Mexico. Census data reveal the presence of economic activities in or near Calakmul incompatible with conservation, and satellite imagery indicates agriculture in several parts of the biosphere, including the nuclear zone. Statistical analysis of the former indicates a significant relationship between population and agriculture, while an evaluation of agricultural suitability in and around Calakmul indicates mixed though often limited potential. As a result, continued population growth in this area will expand the agricultural footprint, likely straining Calakmul management to maintain the conservation function of the biosphere reserve.
A Zoh-Laguna no rubbish sign. How many spelling mistakes can you see?
The reserve consists of a tropical humid forest ecosystem that includes evergreen tropical humid forest, semi-deciduous forest with temporally flooded forest, thorn forest, and tropical deciduous forest. This ecosystem contains considerable biodiversity, including about 250 tree species, 500 butterfly species, 30 amphibian species, 100 reptile species, 280 bird species, and 100 mammal species. Calakmul also is home to a rich collection of (predominantly) Classic Maya archaeological sites, not only increasing the importance of conserving this part of southern Mexico but also providing evidence of substantial prehistoric human occupation in an area that in the late 20th century would experience considerable settlement once again.
Following an historic period of relative seclusion and obscurity, in the 1970s human population began to grow in and around what would become the Calakmul Biosphere Reserve. In large part this is due to programs promoted by the Mexican government to foster development in this region, resulting in population growth in the vicinity of Calakmul. This surge in human population began attracting attention from conservationists who were concerned that the increase in human presence would negatively affect biodiversity in the reserve.
Although historically a remote, sparsely populated area until the 1970s, the region of southern Mexico encompassing the GCR contained large numbers of people more than 1,000 years ago. With evidence of habitation and public building construction as early as 300 BC, the prehistoric Maya capital of Calakmul came to occupy 70 km 2 and contain 50,000 people at its apex during a period of occupation called Late Classic (AD 500-775). The population of Calakmul survived through intensive agriculture (primarily maize). Classic period residents deal with the key limiting factor of water through an elaborate hydraulic system based on water catchments and canals. A combination of factors, including political, economic, and environmental (a prolonged drought), likely contributed to the demise of Calakmul’s Maya civilization during the ninth century AD. Human habitation in the region would not even begin to approach prehistoric levels until the late 20th century.
The Calakmul region is the highest physical part of the Yucatan Peninsula. More than 380 m above the sea level, Calakmul can be considered a plateau settled on calcareous rocks (called Karst), where the rainwater dissolves the calcium carbonate and the water filters underground, forming subterranean rivers. The soils of Calakmul are mainly lithosols and rendzins with an average depth of 10 and 30 cm, respectively. Differences in the drainage capability of the rendzins are responsible for the formation of deep soils (60 cm) which can retain water seasonally, leading to the formation of Lowland flooding forests. These soils are regionally called Ak’alche in the Mayan language.
The GCR, as well as most of the Yucatan Peninsula, does not have any large rivers. The majority of the water runs underground and only collects superficially in soil depressions (cenotes) or is naturally stored in small lagoons and water holes, regionally called “aguadas”. These aguadas play an important role in the landscape because they are the only water source during the dry season for many animal species. In the Calakmul Biosphere Reserve more than 3,000 aguadas have been identified.
The Calakmul climate is classified as warm and sub-humid (Aw), with a mean annual temperature of 24.6° C. There isseasonal summer rainfall, with an annual average of 1076.2 mm. A clearly demarcated humidity gradient decreases from south to north and east to west. The region is a mosaic of different kinds of tropical forest, ranging from low-deciduous forest in the north to tall-evergreen forest in the south eastern extreme. More than 1,600 plant species have been found in Calakmul, and this region contains more than 80 % of the entire number of species in the Yucatan Peninsula with 1,936. Of the different forest associations, four of the most important are:
Medium hight semi-perennial (“evergreen”) forestThis forest type covers more than 50 % of the area. This is a forest where 25–50 % of the species are deciduous (loose their leaves seasonally). Tree height ranges between 15 and 25 m, and the dominants species are: Swietenia macrophylla, Brosimum alicastrum, Lysiloma latisiliqua, Bursera simarouba, Cedrela odorata and Manilkara zapota.
Mixed lowland flooding forest
This forest type covers around 25 to 35 % of the Calakmul area. It occurs on low-drainage soils called Ak’alche in the Mayan language. These forests are seasonally inundated and tree heights are 10 to 15 m. Characteristic species are Haematoxilum campechianum, Bucida buceras, Metopium brownei, Manilkara zapota and Byrsonima bucidaefolia.
Low hight semi-deciduous forest
A third common forest type present in the region is the low semi-deciduous forest, where trees average 15 m tall. Usually these forests are present in the slope of the hills or on the tops where there are many stones and dry soils. Among the species present there are Bursera simarouba, Brosimum alicastrum, Guayacum sanctum, Lysiloma latisiliquia, Cedrela odorata, Vitex gaumery and Lonchocarpus xuul.
Second growth vegetationA mosaic of succesional stages varying in ages from 1 to 25 years old is considered by most botanists as secondary vegetation resulting from slash and burn agricultural practices. This patches are more commonly found within the private and communal lands in the buffer areas of the Calakmul Biosphere Reserve where local ejidatarios still practice slash and burn agriculture as the main subsistence activity. After a few years of crops of corn, beans, squash and chilli the fields (in average one to two hectares in size) are abandoned and the vegetation succesional process begin. Patches of 1 to 5 years old are dominated by early aggressive colonizer plants such as ferns, Ficus sp. and Bursera sp. trees. Older succesional stages (15 years and more) closely resemble the structure and composition of low semi-deciduous forests and sometimes are difficult to distinguish from this vegetation class.
Calakmul is a region with a high diversity of reptiles, birds and mammals. Fish are not well known, and only 18 species have been identified in the area. Sixteen species of amphibians and 50 species of reptiles have been reported for the Calakmul Reserve and 286 species of birds have been observed in the area. Calakmul has 94 species of mammals. Although is not as diverse as other tropical forest in Mexico, Calakmul represents one of the last remaining natural areas for the conservation of several species who need large amounts of habitat such as the tapir (Tapirus bairdii), white-lipped peccary (Tayassu peccary), jaguar (Panthera onca) and king vulture (Sarcoramphus papa), among others. Regarding the ungulate population, Calakmul is one of the most diverse forests in ungulate species from southern Mexico. There are six species of ungulates, including the recently re-discovered Yucatan brown brocket deer (Mazama pandora), the red brocket deer (M. americana), the white-tailed deer (Odocoileus virginanus), two species of peccaries; the collared peccary (Peccari tajacu) and the white-lipped peccary (Tayassu peccari) as well as the last element of Neotropical megafaunal, the Central American tapir (Tapirus bairdii).
If this place is to survive this new period of modern, technologically advanced human colonization, many things have to be tested but perhaps the most important will be the feasibility of the current conservation approach with the Calakmul reserve dominating most -if not all- of the conservation initiatives.
