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YASUNI NATIONAL PARK
The eastern portion of Ecuador in the Amazon Basin (the "Oriente") comprises the lowlands that gradually slope downward from 600 m to less than 200 m at the eastern frontier with Peru (Balslev and Renner 1989; Tschopp 1953). The topography is low and undulating to slightly hilly terrain between broad swampy floodplains of the main rivers. Geologically the Oriente is part of the extensive area filled with Cretaceous-Tertiary sediments between the Andes and the Brazilian Shield (Tschopp 1953).
This region is drained by the Napo and Pastaza river systems, which diverge respectively toward the north-east to east and the south-east from the depression between the Andean uplifts of the Serranía del Napo (with Sumaco Volcano) and the Sierra de Cutucú (Tschopp 1953). The Napo is the major river, flowing eastward to join the Marañón River near Iquitos, Peru (CPD Site SA9) and form the Solimões River, which in turn flows eastward to Manaus, Brazil (CPD Site SA5).
Yasuní National Park covers 9820 km² south of the Napo River and north of the Curaray River in Napo and Pastaza provinces of central eastern Ecuador, extending eastward from c. 40 km east of the town of Coca (76°40'W) almost to Nuevo Rocafuerte near the border with Peru (Map 44). Much of the park's northern boundary is the Tiputini River and much of the southern boundary is the Curaray River. There is a roughly rectangular north-western extension of the park to the south bank of the Napo River at Añangu and westward to the Indillama River.
The adjacent Waorani Ethnic Reserve includes 6100 km². The eastern part of the reserve is largely encompassed to the north, east and south by the park. The reserve extends westward to c. 77°30'W, but is almost bisected by the Auca road which runs south from the town of Coca (or Puerto Francisco de Orellana), an oil centre and port. A broad swath of land 10 km wide on either side of the road is occupied by colonists, but more or less south of the road a corridor provides the Waorani Amerindians access between the eastern and western portions of their reserve.
Most of the park and reserve has low hills of red clay dystropept soil. Low humic gley soil probably occurs in the swampy or poorly drained areas in the eastern part of the park (Duellman 1978; Neill 1988b). There are no peat swamps or podzols (Balslev and Renner 1989).
Weather stations some distance west and east of the park suggest that the annual temperature averages 25°C (with extremes of 15° and 38°) and the annual rainfall is 2425-3145 mm, with a humidity of 88%. Although rarely rainless for more than c. 10 days, between August and February some months may be drier (Balslev et al. 1987; Blandin Landívar 1976; Duellman 1978). Flooding is not seasonal (Balslev and Renner 1989).
The entire region is within the tropical moist-forest life zone of the Holdridge system. The park and reserve are in the Solimões-Amazonas phytogeographic region (Nations 1988). Four main vegetation types have been recognized within the park and reserve, but the vegetation has not been mapped.
1. Probably more than 90% of the area is unflooded upland ("tierra-firme") forest, occurring on the low hills of red clay dystropept soil. The canopy is 25-30 m high, with emergents such as Cedrelinga cateniformis (to 45-50 m tall and 2-3 m dbh) and Parkia spp. Canopy trees include several Myristicaceae (Otoba glycycarpa, Osteophloeum platyspermum, Virola spp.). Simaruba amara, Dussia tessmannii, Hymenaea oblongifolia and several genera of Moraceae and Sapotaceae also occur. Trees with buttresses or stilt roots are frequent. The understorey on hills may be quite open with small trees and shrubs, lianas may be abundant, and epiphytes are less diverse and abundant than in wetter forest nearer the Andes (Neill 1988b). The ground layer tends to be only weakly developed (Balslev et al. 1987).
2. Along the banks of the Napo River is a narrow strip (200-1000 m wide) of relatively fertile soil, enriched by sediments from the Andes when the river floods. This "várzea" forest is generally flooded only once every several years. The canopy layer is somewhat higher (35-40 m) than in the upland forest, with occasional emergents such as Ceiba pentandra and Ficus spp. to 50 m tall. Common canopy dominants include Otoba parvifolia, Chimarrhis glabriflora, Celtis schippii and Guarea kunthiana. The ivory-nut palm Phytelephas macrocarpa is a common small understorey tree.
3. The third type of vegetation is swamp forest, which occurs in extensive stands along the Napo River and the lower reaches of the Tiputini River, a main tributary of the Napo. Swamp forest is flooded for much of the year, but the ground is exposed during dry periods. Characteristic are nearly pure stands of the palm Mauritia flexuosa, as well as a few other swamp species such as Virola surinamensis and Symphonia globulifera.
4. The Yasuní River is a black-water river, which bears very little sediment because its headwaters are in the Amazon lowlands rather than the Andes. The waters are stained the colour of dark tea by tannic acids dissolved from riverside vegetation. Along the banks of this river and associated lagoons is "igapó" forest, which is almost totally floristically distinct from the upland and várzea forests. Common trees include Macrolobium acaciifolium, Coussapoa trinervia and the palm Astrocaryum jauari.
The Napo River region of Ecuador and Peru has been proposed as one of the primary Pleistocene forest refugia, characterized by a high degree of animal and plant endemism. The refugium extends from the foothills of the Andes eastwards to the "Trapecio Amazónico" of Colombia and Peru (Duellman 1978; Prance 1982) - the park and reserve are within a more finely delimited South Napo Pleistocene refugium.
The upper part of the Amazon Basin may have emerged from a mid-continental lake and become forested as recently as 1.8 million years ago, with the greatest uplift of the Andes. During climatic fluctuations of the Pleistocene and Holocene the forest may have become fragmented, and then rejoined north and south but been separated by drier areas to the east (e.g. Duellman 1978). For the Oriente as a whole, which however is just a part of the postulated Pleistocene refugium, Balslev and Renner (1989) estimated endemism at only 1%. The plant species composition of the park and reserve remain unknown, as does the extent of regional endemism represented within them.
The little collecting and study done so far at one area (Añangu) showed high but not exceptional richness for moist lowland forest (Balslev and Renner 1989). Some 394 species of trees over 10 cm dbh were found: 153-228 species per ha in unflooded forest and 146 in floodplain forest, with 19% shared. As usual in the neotropical lowlands, Moraceae and Leguminosae were most frequent. So little known is the region that in two weeks of field work near an exploratory oil well in the western part of the park, several new species of trees and at least two new orchid species were discovered, as well as over 15 records of orchids new for Ecuador (Neill 1988b). The flora of the region contains many species in common with the lowlands of the nearby Gran Sumaco and Upper Napo River region (see Gran Sumaco Data Sheet, CPD Site SA38), but the distribution of the flora in Amazonian Ecuador is highly heterogeneous - many species present in the wetter Gran Sumaco region do not occur in the Yasuní region, and vice versa.
In late 1992, botanists from the National Herbarium of Ecuador and the Missouri Botanical Garden initiated a large-scale floristic inventory along the oil-pipeline road which is being built through 120 km of primary forest in the Yasuní National Park and Waorani Ethnic Reserve. Specimens were collected from felled trees. This survey has continued for two years and will provide much more thorough knowledge of the flora.
Little that is definitive can be said until the flora is better known. Hevea guianensis is present - a less commercially desirable rubber tree than H. brasiliensis, but an important genetic resource. Phytelephas macrocarpa (the vegetable-ivory palm) also is found - a species that has received renewed international commercial interest. Cedrelinga cateniformis, which is prized for construction of dugout canoes, has potential as a commercial timber. This species might replace the dwindling Spanish cedar (Cedrela odorata) and bigleaf mahogany (Swietenia macrophylla), which are among the valuable timber trees selectively taken from accessible areas along the rivers.
Ethnobotanical studies in lowland Ecuador (Kvist and Holm-Nielsen 1987) include various medicinal and other uses of species by the Waorani (Davis and Yost 1983): e.g. Bactris gasipaes (blowgun wood), Curarea tecunarum (arrow poison and fungal diseases), Minquartia guianensis (fish poison), Banisteriopsis muricata (hallucinogen), Renealmia spp. and Urera baccifera (snake bites), Piper augustum and P. conejoense (toothbrush and decay preventive), Sphaeropteris sp. (local dental anesthetic), Virola spp. and Iryanthera spp. (fungal diseases).
Social and environmental values
The park and reserve provide extensive habitat for many animals, e.g. harpy eagles, macaws, jaguars, primates, freshwater dolphins and anacondas. The area's great expanse provides a rare chance to conserve unfragmented and undisturbed ecosystems and populations functioning naturally, including threatened species.
The two protected areas are embraced by the large Napo and Upper Amazon lowlands Endemic Bird Area (EBA B19), which extends from southernmost Colombia and eastern Ecuador eastward into northern Peru and westernmost Brazil. Ten species of birds are limited to this area, although they essentially represent the most restricted species of a (distributionally poorly known) suite of birds that are confined to the river islands, riverine forest and várzea forest of the Amazon Basin rivers. The birds in this EBA, just one of which is considered threatened, are seemingly confined to the tierra-firme or várzea forests.
The Waorani Ethnic Reserve protects tribal land of the Waorani ("Auca") Amerindians, some of whom have fiercely resisted all outside efforts to contact them (Nations 1988; Whitten 1981; Yost 1981). Oil exploration began in their area in the 1940s. The Waorani ethnobotany is notably different from that of neighbouring peoples, suggesting their past isolation. Several family groups of Waorani live in the eastern portion of Yasuní park.
In 1992, a large-scale conservation programme known as SUBIR (Sustainable Use of Biological Resources) was initiated for the Yasuní region as well as two other protected areas in Ecuador. The goals of SUBIR are to promote conservation by increasing the capacity of Ecuadorian agencies to protect core areas, as well as encouraging non-destructive uses of natural resources by peoples living in buffer zones around the protected areas. Financed by the U.S. Agency for International Development, SUBIR is carried out by a consortium of organizations led by CARE International, with the collaboration of the Ecuadorian Ministerio de Agricultura y Ganadería (Ministry of Agriculture and Livestock) and local environmental and community organizations.
The SUBIR programme seeks to help develop viable economic alternatives that will enable people in the buffer zones to produce sufficient income without causing deforestation or other resource-destructive activities. These alternatives may include ecotourism, production of handicrafts and other goods from the forest, and improved agricultural techniques that obviate the need to continually clear more forested land. SUBIR is an experiment in its initial stages; its results will not be evident for several years.
The forests of Ecuador's Oriente are undergoing extensive deforestation as a result of oil exploration and production followed by colonization, which began with the most recent and successful phase of exploration in 1964-1969 (Schodt 1987). These activities led to the construction of a 420-km oil pipeline to transport petroleum from the Oriente oil fields over a 4300-m high pass in the Andes and down to the port of Esmeraldas on the Pacific coast. With the pipeline, the first roads were constructed into Ecuador's north-eastern Amazon and then south, in 1971 opening the region to colonization, e.g. through relocation of farmers from the over-crowded coastal and mountain regions of the country (Bromley 1973; Neill 1988a). Where a few thousand lived 20 years ago, now over 100,000 people live in Napo Province and are transforming large tracts of forest into agricultural fields and pastures (Uquillas 1984). African oil palm (Elaeis guineensis) is the favourite plantation crop. Selective logging occurs where the trees are accessible.
In the mid 1980s, new oil fields were located in the Pastaza and Napo river valleys, including a significant reserve of 150 million barrels of heavy crude petroleum beneath the Waorani Ethnic Reserve and Yasuní National Park. Ecuador's plan for extraction by building a road as well as a pipeline to the oil fields through the untouched Yasuní forest, instead of flying in materials, sparked intense controversy within Ecuador as well as internationally. The government's PetroEcuador awarded a concession for development of the oil reserves in petroleum block 16, which occupies 2000 km² within the Waorani reserve, to the U.S.-based company Maxus. In December 1992, construction of the road and pipeline began from the Napo River south into the centre of the Waorani reserve-Yasuní park territory, amid continuing opposition from Ecuadorian environmental organizations.
The environmental mitigation plan for the development project within the Yasuní-Waorani area includes some provisions for reducing negative impacts. Strict control of persons entering the road is planned to avoid settlers and logging, and wells are to be drilled in clusters to reduce deforestation. However, the feasibility of being able to prevent invasion of the park and reserve by colonists once the road is established is questionable. The events that often follow the building of a road in a protected area are sadly recorded nearby. Construction of oil-pipeline roads through the Cuyabeno Wildlife Reserve north of the Napo River led to colonization of the area by more than 1000 families.
The discovery of oil in the Oriente has brought considerable prosperity to Ecuador (oil exports provide 70% of the country's income) (Schodt 1987), greatly increased opportunities for colonization in the region and emphasized the need to protect its diverse biological resources - which also are of economic significance. Two large reserves were created in 1979: Cuyabeno Wildlife Reserve (2547 km²) north of the Napo River and Yasuní National Park (originally 6797 km²) - the largest mainland park in Ecuador.
Due in part to the conflict between conservation of protected areas and development of oil fields, the size and shape of Yasuní park have been changed twice by governmental decrees. An ethnic reserve of 1600 km² for the Waorani was established in 1968, south-west of the original Yasuní park boundary (Whitten 1981). Until the 1960s, the Waorani were nomadic over c. 20,000 km² (nearly all of the territory between the Napo and Curaray rivers) and their hostile reactions to all outsiders had kept their land nearly undisturbed (e.g. Kvist and Holm-Nielsen 1987).
In 1990, the Waorani Ethnic Reserve was enlarged eastward to 6100 km², and a large part of Yasuní park was ceded to the Waorani reserve, including the major portion of the oil fields near the Yasuní River. As partial recompense for loss of the park lands, additional territory was added on the south-east of Yasuní NP. In 1992, the park was enlarged again to 9820 km². Together with the Waorani reserve, the officially protected Yasuní region now comprises almost 16,000 km².
An important step toward the legal protection of the region was the May 1989 declaration of the park and its buffer zone as a Biosphere Reserve, under UNESCO's Man and the Biosphere Programme (Coello Hinojosa and Nations 1989). The Biosphere Reserve now includes the Waorani Ethnic Reserve and the enlarged Yasuní NP. However, the future of the park and reserve remain uncertain. The oil reserves will last only 20 years. Over the long term it will be more productive to protect the genetic resources of the region and promote tourism that can generate steady income. Future generations of Ecuadorians especially could have the legacy of a great Amazonian park, the homeland of indigenous people, and an extraordinary representation of plant and animal species in one of the world's diverse large wilderness regions.
A preliminary master plan for the park has been prepared by the Departamento de Administración de Areas Naturales y Vida Silvestre of the Ministerio de Agricultura y Ganadería (Coello Hinojosa and Nations 1989). However, the changing boundaries of the park, the establishment of the Waorani Ethnic Reserve and the petroleum development necessitate thorough revision of the management plan for the region. Legal mechanisms for future management and environmental protection of the Waorani Ethnic Reserve, in particular, have not been clarified by the government. The conservation outlook for the Yasuní region is not yet bleak - the Maxus petroleum company which holds the development concession in the area has demonstrated a commitment to support conservation efforts.
Among other contributions, Maxus agreed to build a scientific research station within the park, which is to be managed by the Pontificia Universidad Católica del Ecuador, Quito. The first major research project of the station is studying the forest dynamics of a diverse 50-ha permanent plot established on the Tiputini River (Foster 1994).
Map 44. Yasuní National Park and Waorani Ethnic Reserve, Ecuador (CPD Site SA8)
Balslev, H., Luteyn, J., Øllgaard, B. and Holm-Nielsen, L.B. (1987). Composition and structure of adjacent unflooded and floodplain forest in Amazonian Ecuador. Opera Botanica 92: 37-57.
Balslev, H. and Renner, S.S. (1989). Diversity of east Ecuadorean lowland forests. In Holm-Nielsen, L.B., Nielsen, I. and Balslev, H. (eds), Tropical forest: botanical dynamics, speciation and diversity. Academic Press, London. Pp. 287-295.
Blandin Landívar, C. (1976). El clima y sus características en el Ecuador. Biblioteca Ecuador. XI Asamblea General del Instituto Panamericano de Geografía e Historia, Quito. 86 pp.
Bromley, R.J. (1973). Agricultural colonization in the upper Amazon Basin: the impact of oil discoveries. Tijdschr. Econ. Soc. Geogr. 63: 278-294.
Coello Hinojosa, F. and Nations, J.D. (1989). Plan preliminar de manejo del Parque Nacional Yasuní 'Reserva de la Biósfera'. Ministerio de Agricultura y Ganadería, Dirección Nacional Forestal, Departamento de Areas Naturales, Quito. 121 pp.
Davis, E.W. and Yost, J.A. (1983). The ethnobotany of the Waorani of Eastern Ecuador. Bot. Mus. Leafl. Harvard Univ. 29: 159-217.
Duellman, W.E. (1978). The biology of an equatorial herpetofauna in Amazonian Ecuador. University of Kansas Museum of Natural History, Miscellaneous Publication No. 65. 352 pp.
Foster, R.B. (1994). 50-hectare plot being established in Yasuní National Park, Ecuador. Inside CTFS (Fall 1994): 11.
Kvist, L.P. and Holm-Nielsen, L.B. (1987). Ethnobotanical aspects of lowland Ecuador. Opera Botanica 92: 83-107.
Nations, J.D. (1988). Road construction and oil production in Ecuador's Yasuní National Park. Center for Human Ecology, Antigua, Guatemala. 18 pp. + 3 maps. Unpublished.
Neill, D.A. (1988a). A field trip in Ecuador: oil wells, Indians and rainforests of the Upper Amazon. Missouri Bot. Gard. Bull. 76(3): 5-7.
Neill, D.A. (1988b). The vegetation of the Amo 2 oil well site, Yasuní National Park, Napo Province, Ecuador. 4 pp. Unpublished.
Prance, G.T. (1982). Forest refuges: evidence from woody angiosperms. In Prance, G.T. (ed.), Biological diversification in the tropics. Columbia University Press, New York. Pp. 137-158.
Schodt, D.W. (1987). Ecuador: an Andean enigma. Westview Press, Boulder, Colorado, U.S.A. 188 pp.
Tschopp, H.J. (1953). Oil explorations in the Oriente of Ecuador, 1938-1950. Bull. Amer. Assoc. Petrol. Geol. 37: 2303-2347.
Uquillas, J. (1984). Colonization and spontaneous settlement in the Ecuadorian Amazon. In Schmink, M. and Wood, C.H. (eds), Frontier expansion in Amazonia. University of Florida Press, Gainesville. Pp. 261-284.
Whitten Jr., N.E. (1981). Amazonia today at the base of the Andes: an ethnic interface in ecological, social and ideological perspectives. In Whitten Jr., N.E. (ed.), Cultural transformations and ethnicity in modern Ecuador. University of Illinois Press, Urbana. Pp. 121-161.
Yost, J.A. (1981). Twenty years of contact: the mechanisms of change in Wao ("Auca") culture. In Whitten Jr., N.E. (ed.), Cultural transformations and ethnicity in modern Ecuador. University of Illinois Press, Urbana. Pp. 677-704.
This Data Sheet was written by Olga
Herrera-MacBryde (Smithsonian Institution, SI/MAB Program, S. Dillon Ripley Center, Suite
3123, Washington, DC 20560-0705, U.S.A.) and Dr David A. Neill (Missouri Botanical Garden,
P.O. Box 299, St. Louis, MO 63166, U.S.A. and Herbario Nacional del Ecuador, Casilla
17-12-867, Quito, Ecuador).
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