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ECUADORIAN PACIFIC COAST MESIC FORESTS
The Pacific coastal region of Ecuador is mainly a relatively broad plain (30-70 km wide) west of the Andes. This region is drained by two major river systems: the Esmeraldas River in the north, and the Guayas River system in the central portion, which drains southward. West of the coastal plain and parallel to the Andes is the Cordillera de la Costa, with peaks over 800 m.
Climatically, the coastal region is characterized by a steep gradient of annual precipitation. The wettest area, near the Colombian border in the extreme north, receives more than 8000 mm of rainfall annually. Due to the influence of the marine Humboldt Current off the coast of South America, the coastal Ecuadorian climate is progressively drier to the south and west. In the south-west, the Santa Elena Peninsula receives less than 100 mm of rain annually and is classified as tropical desert (Cañadas-C. 1983).
This site description includes the relatively moist to pluvial northern and central parts of coastal Ecuador with annual rainfall of 2000 mm or more (zonal maps are in Dodson and Gentry 1991). This mesic region (Map 75) is in the coastal range, coastal plain and western slopes of the Andes to 900 m elevation. Pluvial forest, the wettest zone in the Holdridge life-zone system, covered a relatively small area (8000 km²) in extreme northern Ecuador along the base of the Andes. Wet forest occupied 12,000 km² in a zone broad in the north that tapers in southern Ecuador to a band less than 1 km wide at the base of the Andes, and also occurs in small isolated patches on higher parts of the coastal range. South and west of the wet-forest life zone, moist forest occupied a large area (32,000 km²) of the plain and coastal range. To the south and west of the moist-forest life zone is dry forest, with annual rainfall less than 2000 mm and a strong dry season of more than four months. (The Ecuadorian coastal dry forest is not included in this Data Sheet - this formation extends southward into Peru's Tumbes Province and is described in the Data Sheet on Cerros de Amotape National Park region, CPD Site SA41).
The once continuous lowland wetter forests of coastal Ecuador have been fragmented and reduced to a few remnants (Dodson and Gentry 1991). The remaining patches of intact forest are quite distinct from one another in structure and species composition. Certainly the original forests varied considerably, depending upon local soils and climatic conditions. Very little quantitative information is available on the vegetation of this region. Botanists from the Herbario Nacional del Ecuador and Missouri Botanical Garden established a series of permanent 1-ha study plots in 1993 in forests of the Cotacachi-Cayapas Ecological Reserve, which can provide data for comparison with similar plots established through the neotropics (Gentry 1988; Campbell 1989).
The vegetation (cf. Neill 1992) on a forest remnant of 2.00 km² maintained as a reserve by the timber company ENDESA (Enchapes Decorativos) on its Pitzara River lands (0°20'N, 79°20'W) just south of the Guayllabamba River probably is rather typical of the forest that once covered this region. The canopy is c. 40 m high and fairly continuous, with few gaps. The absence of gaps and the relative abundance of large trees (dbh 70 cm or more) are striking features in comparison with Amazonian Ecuador's forest, where gaps appear to be more frequent and there are fewer large trees.
Among the large and common canopy tree species in primary forest are Brosimum utile, Guarea kunthiana, Carapa guianensis, Dacryodes sp., Pouteria capacifolia, Virola dixonii and Huberodendron patinoi. Occasional emergent trees over 60 m tall are present, e.g. the strangler fig Ficus dugandii. The subcanopy is dominated by two species of very abundant palms, the stilt-rooted Iriartea deltoidea and Wettinia quinaria; also very common are several species of Matisia (Bombacaceae). The understorey is dense and composed of many species of Rubiaceae and small palms, mostly Geonoma species. Covering the lower trunks of most of the forest's trees are diverse and very abundant epiphytic Araceae, Cyclanthaceae and ferns.
Although there are several partial floristic studies for western Ecuador, floristically the region remains quite poorly known. An illustrated guide to common trees of Esmeraldas Province was prepared (Little and Dixon 1969) as part of a forestry development project in the 1960s supported by the United Nations Food and Agriculture Organization (FAO). For the Río Palenque Science Center's Forest Reserve (1 km²) in the tropical wet forest of the Guayas River Basin, Dodson and Gentry (1978) wrote an illustrated Florula. Farther south, for the Jauneche Reserve (1.30 km²) in the tropical moist forest, Dodson, Gentry and Valverde (1986) published a comparable Florula. Considering the 283 genera found at one or both sites, the generic similarity between the latter two sites is fairly high at 0.59, using the Sørensen coefficient (Dillon 1994).
Botanists from the Pontificia Universidad Católica del Ecuador, Quito and the University of Aarhus, Denmark have made floristic studies in a Forest Reserve (0.80 km²) of the ENDESA timber company in western Pichincha Province (Jørgensen and Ulloa 1989). The Herbario Nacional del Ecuador and Missouri Botanical Garden are carrying out intensive floristic inventories in Awá Ethnic Forest Reserve and Cotacachi-Cayapas Ecological Reserve.
The Río Palenque Science Center (0°30'S, 79°20'W), between Quevedo and Santo Domingo de los Colorados, is the most thoroughly studied site in coastal Ecuador. At Río Palenque is the only remaining primary forest on the fertile soils of the Upper Guayas Basin - a fragment of just 1 km. Over 1100 species in 123 families have been recorded at Río Palenque; 20% of the species are local endemics, and 23 are known only from this reserve (Dodson and Gentry 1978).
Non-tree species - including epiphytes, lianas, shrubs and terrestrial herbs - are a very significant portion of the overall diversity of the plants in tropical forests. In the forests of coastal Ecuador, epiphytes are a particularly species-rich element of the floras. At Río Palenque, a 0.1-ha sample had 365 vascular plant species, the world's most species-rich site studied with the method: the species were 35% epiphytes (including hemi-epiphytes); 31% trees (including all juveniles), 24% with dbh 2.5-10 cm, 9% with dbh 10 cm or more; 14% terrestrial herbs (including palmettos); 11% shrubs; and 10% climbers (excluding the hemi-epiphytes) (Gentry and Dodson 1987).
In contrast to the very high diversity of epiphytes in these forests, the diversity of trees and shrubs is relatively low. Gentry (1992) carried out a series of sample transects in western Ecuadorian forests, recording plants with dbh 2.5 cm or more in 0.1-ha plots. The three moist-forest sites had a mean of 96 species and the four wet-forest sites a mean of 125 species. Neotropical lowland moist/wet forest averages 152 species in equivalent samples (Gentry 1988).
Another method of estimating [alpha] diversity in tropical forests involves enumerating all trees with dbh 10 cm or more in 1-ha sample plots (Campbell 1989). In Upper Amazonia and in the Colombian Chocó region north of coastal Ecuador (CPD Site SA39), 250-300 species of trees may occur in such plots (Gentry 1988; Faber-Langendoen and Gentry 1991). In western Ecuador, preliminary information indicates that the number of tree species probably exceeds 150 per ha (Palacios and Neill, in prep.). With respect to the diversity of tree species, the wet forests of western Ecuador may be more similar to those of Central America than Upper Amazonia.
The extant overall floristic diversity of coastal Ecuador will not be known unless more thorough inventories are carried out in all its vegetation types (cf. Dillon 1994). Dodson and Gentry (1991) estimated that 6300 vascular plant species occur in coastal Ecuador including the lower western slopes of the Andes up to 900 m, with 20% endemic (1260 species). About 1000 of the species occur only in dry forests, so the estimated total for moist, wet and pluvial forests is 5300 species, with 20% endemic - 1060 species. Although the a diversity of trees in this region is low compared to the diversity in Upper Amazonia, the broad range of habitats does support a very diverse regional flora with a high degree of endemism.
Gentry (1992) provided a concise phytogeographic overview of coastal Ecuador based on information that became available in the preceding several years: "Coastal Ecuador is of conservation significance for its high plant endemism ... What has not been appreciated previously is that the unusual high endemism of western Ecuador moist and wet forests is associated with relatively species-poor forests ... The pattern that results is a new and interesting one that focuses on western Ecuador (i.e., south of the town of Esmeraldas) as a unique and distinctive floristic region for wet and moist forest as well as for dry-forest vegetation, rather than as the tail-end of the [Colombian] Chocó flora as I had previously interpreted it ... This forest is characterized by low species diversity of trees (but high diversity of epiphytes), high endemism, a predominance of hemi-epiphytic climbers (also characteristic of the Chocó), unusually low levels of such characteristic taxa as Bignoniaceae and Leguminosae, and high levels of Araceae, Piperaceae, Moraceae and Cucurbitaceae".
North-western Ecuador and especially the lowland forests of Esmeraldas Province have provided almost all timber for the country for the last several decades. One of the most important trees, a prime timber for construction in Quito and other Ecuadorian cities, has been the locally endemic Humiriastrum procerum (Humiriaceae), which occurs only in wet forests north of the Guayllabamba River. The supply of this hardwood has been severely depleted by logging and the natural regeneration of this slow-growing species in logged-over forests appears to be very poor. Other trees important to the timber industry include soft-wooded species used for plywood, such as Brosimum utile, Dacryodes sp. and Virola dixonii.
One of the most characteristic plants of coastal Ecuador is the endemic ivory-nut palm or "tagua" Palandra aequatorialis (Phytelephas aequatorialis). This small tree (to 15 m) is common in the understorey of the natural forests throughout the region. The mature seed's endosperm is like ivory white and hard. In the 1920s-1930s before the invention of synthetic plastics, vast quantities of ivory nuts were exported from Ecuador to the U.S.A. and Europe where they were used by the garment industry to manufacture buttons. Recently, with the worldwide CITES ban on elephant ivory, there has been renewed commercial interest in this vegetable ivory. Conservation International is carrying out the Tagua Initiative project to promote sustainable harvest of the ivory nuts in rural communities in Esmeraldas Province as a means of protecting the forests in which this species occurs (Calero-H. 1992; Ziffer 1992).
The flora of coastal Ecuador includes many plant species with potential as ornamentals, especially the diverse epiphytic taxa. Anthurium andraeanum, one of the world's most widely cultivated house-plants, is native to the north-western corner of Ecuador as well as the southern Colombian Chocó. Numerous endemic species of Gesneriaceae in coastal Ecuador have potential as ornamentals, but relatively few have been brought into cultivation.
Social and environmental values
The wet forests of north-western Ecuador are home to two indigenous ethnic groups, which practise traditional subsistence agriculture and hunting and gathering in relatively large tracts of intact forest. The Awá (Coaquier) live on both sides of the Colombia-Ecuador border. In Ecuador, c. 2200 Awá inhabit the Awá Ethnic Forest Reserve (1300 km²) (Map 75). They clear only small patches for cultivation of plantains (Musa × paradisiaca) and other subsistence crops; their ethnobotany is being studied.
Further south, in the area around the Cayapas River, live the Chachi (Cayapa). About 3000 Chachis occupy 300 km² of lowland wet forest just west of the Cotacachi-Cayapas Ecological Reserve.
Both the Awá and the Chachi require large tracts of undisturbed forest to continue their traditional life-styles. These indigenous peoples should have an increasingly important role in conservation of these remaining moist and wet forests.
In the north of this region (southward to northern Guayas), bird species of restricted range from the Chocó and Pacific slope of the Andes Endemic Bird Area (EBA B14) are present in the wet and moist forests; c. 37 of 62 restricted-range species occur. Farther south in the moist and dry forests, species from the Tumbesian western Ecuador and Peru EBA (B20) predominate, with up to 55 restricted-range species present. Currently 30 species from these EBAs are considered threatened.
As early as the 1600s, the forests of western Ecuador were logged to provide wood for the ship-building industry that had started on the coast of Ecuador. Later cacao plantations replaced much of the forests.
Acosta-Solís (1947) mentions that original forest was only to be found in remote locations. No known reports suggest to what extent those forests once existed, but it is likely that they covered large portions of the country. He also suggested that only five regions were worth logging and each of them contained some wet forest. Plantations of fast-growing species to be used for paper pulp were recommended to replace the cleared native forest.
Until 1960, transportation into the wet forests was mainly by canoe using the extensive system of rivers throughout the forest. Since then roads have been constructed and improved, and under Ecuador's colonization law, people were allowed to clear forested areas and plant crops. The most prevalent cash crops are plantations of oil palms and bananas. By 1970, virtually all of the moist forest and much of the wet forest had been lost. Myers (1988) pointed out that due to this region's species diversity and high endemism, it is of considerable scientific interest. With the increased and rapid destruction of habitats, he ranked the Ecuadorian coastal wet forest as one of the world's areas most in need of protection.
Logging and colonization continue in the region, mostly in remote areas of Esmeraldas Province in the north. The largest continuous tract of forest remaining in coastal Ecuador outside of established reserves is the lands (300 km²) of the Chachi Amerindians along the Cayapas River. Ecuadorian timber companies are attempting to make agreements with the Chachis for the sale of timber rights on these lands. Conservation efforts such as the programme SUBIR (Sustainable Use of Biological Resources) are attempting to collaborate with the Chachi to develop long-term, sustainable management plans for their forests.
The largest conservation unit in the region is the Cotacachi-Cayapas Ecological Reserve (2040 km²), established in 1970 and accorded permanent status in 1979. Cotacachi-Cayapas preserves the greatest diversity of ecological regions in the country, ranging from high- Andean páramos and cloud forests on the western slopes of the Andes down to coastal forests at 200 m elevation (SFRNR 1991). About 40% of the reserve (c. 800 km²) is below 900 m in the lowland forest zone (Map 75).
In 1992, the large-scale conservation programme SUBIR was initiated in the region around the Cotacachi-Cayapas Ecological Reserve, as well as for two other protected areas in Ecuador. SUBIR's goals are to promote conservation by increasing the capacity of Ecuadorian agencies to protect the core natural areas, as well as by non-destructive use of the natural resources by the people living in buffer zones around the protected areas. (For more on the SUBIR programme, see the Data Sheet on Yasuní National Park and Waorani Ethnic Reserve, CPD Site SA8).
The Awá Ethnic Forest Reserve (1300 km²) is another important conservation unit in western Ecuador; c. 800 km² are below 900 m (Map 75). This reserve was established as part of a binational agreement of Colombia and Ecuador; additional territory has been set aside for the Awá on the Colombian side of the border. Both governments are participating with Awá indigenous organizations in carrying out conservation as well as rural development programmes in this region. Most of the Awá reserve is accessible only by footpaths.
The ENDESA timber company has 50 km² of land in western Ecuador. Most was purchased from colonists who had cut the timber and grown crops or established pastures; the company has reforested the land for industrial timber plantations to produce plywood. ENDESA's holdings include c. 3 km² of primary forests, which it has promised to maintain as reserves. The ENDESA forests are virtually the only remaining undisturbed forests in lowland Pichincha Province, north of the city of Santo Domingo de los Colorados.
South of the Equator in coastal Ecuador there are very few patches of intact forest remaining, and they are very small. The forest of 1 km² at the privately owned Río Palenque Science Center is all that remains of primary wet forest in the Guayas River Basin. Since the 1960s the forest surrounding the field station has been converted into plantations of oil palms and bananas. Similarly, the forest of 1.30 km² at the Jauneche Reserve, which is owned by the Universidad de Guayaquil, is virtually all that remains of primary moist forest in the Guayas Basin.
Some larger fragments of wet and moist forests still exist in as yet inaccessible areas of the coastal range, west of the Guayas Basin and south of the city of Esmeraldas (Map 75). However, these remnants are rapidly disappearing as colonists cut the forests higher and higher on the slopes. There is as yet no formal protection for forest remnants in the coastal range.
Map 75. Ecuadorian Pacific Coast Mesic Forests, Ecuador (CPD Site SA40)
Acosta-Solís, M. (1947). Commercial possibilities of the forests of Ecuador - mainly Esmeraldas Province. Tropical Woods 89: 1-47.
Calero-H., R. (1992). The Tagua Initiative in Ecuador: a community approach to tropical rain forest conservation and development. In Plotkin, M. and Famolare, L. (eds), Sustainable harvest and marketing of rain forest products. Island Press, Washington, D.C. Pp. 263-273.
Campbell, D.G. (1989). Quantitative inventory of tropical forests. In Campbell, D.G. and Hammond, H.D. (eds), Floristic inventory of tropical countries. New York Botanical Garden, Bronx. Pp. 524-533.
Cañadas-C., L. (1983). El mapa bioclimático y ecológico del Ecuador. Ministerio de Agricultura y Ganadería, Programa Nacional de Regionalización (MAG-PROMAREG), Quito. 210 pp.
Dillon, M.O. (1994). Bosques húmedos del norte del Perú. Arnaldoa 2(1): 29-42.
Dodson, C.H. and Gentry, A.H. (1978). Flora of the Río Palenque Science Center, Los Ríos, Ecuador. Selbyana 4: 1-628.
Dodson, C.H. and Gentry, A.H. (1991). Biological extinction in western Ecuador. Ann. Missouri Bot. Gard. 78: 273-295.
Dodson, C.H., Gentry, A.H. and Valverde, F. de M. (1986). La Flora de Jauneche, Los Ríos, Ecuador. Selbyana 8: 1-512.
Faber-Langendoen, D. and Gentry, A.H. (1991). The structure and diversity of rain forests at Bajo Calima, Chocó region, western Colombia. Biotropica 23: 2-11.
Gentry, A.H. (1988). Changes in plant community diversity and floristic composition on geographical and environmental gradients. Ann. Missouri Bot. Gard. 75: 1-34.
Gentry, A.H. (1992). Phytogeographic overview. In Parker III, T.A. and Carr, J.L. (eds), Status of forest remnants in the Cordillera de la Costa and adjacent areas of southwestern Ecuador. RAP Working Pap. 2, Conservation International, Washington, D.C. Pp. 56-58.
Gentry, A.H. and Dodson, C.H. (1987). Contribution of nontrees to species richness of a tropical rain forest. Biotropica 19: 149-156.
Jørgensen, P.M. and Ulloa-U., C. (1989). Estudios botánicos en la "Reserva ENDESA" Pichincha, Ecuador. Botanical Institute, University of Aarhus, Denmark. AAU Reports 22. 216 pp.
Little Jr., E.L. and Dixon, R.G. (1969). Arboles comunes de la Provincia de Esmeraldas, Ecuador. Estudio de preinversión para el desarrollo forestal del noroccidente, Ecuador; Informe final, Tomo IV. FAO/SF: 76/ECU 13. United Nations Development Program, Food and Agriculture Organization (FAO), Rome. 536 pp.
Myers, N. (1988). Threatened biotas: hot-spots in tropical forests. The Environmentalist 8: 187-208.
Neill, D.A. (1992). ENDESA/BOTROSA [Enchapes Decorativos, S.A. / Bosques Tropicales, S.A.] reforestation project, Ecuador: study of project's impact on regional plant diversity. Herbario Nacional del Ecuador, Quito. 13 pp. Unpublished report.
SFRNR (1991). Reserva Ecológica Cotacachi-Cayapas. In Sistema Nacional de Areas Protegidas y la vida silvestre del Ecuador. MAG, Subsecretaría Forestal y de Recursos Naturales Renovables (SFRNR) and U.S. Fish and Wildlife Service, Quinto. Pp. 32-34.
Ziffer, K. (1992). The Tagua Initiative: building the market for a rain forest product. In Plotkin, M. and Famolare, L. (eds), Sustainable harvest and marketing of rain forest products. Island Press, Washington, D.C. Pp. 274-279.
This Data Sheet was written by Dr David A. Neill (Missouri Botanical Garden, P.O. Box
299, St. Louis, MO 63166-0299, U.S.A. and Herbario Nacional del Ecuador, Casilla
17-12-867, Quito, Ecuador).
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