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LOWLANDS OF MANU NATIONAL PARK:
Manu National Park, one of the largest and most significant National Parks in South America, extends from above 4000 m in the Andean Cordillera of Peru's Department of Cuzco to 300 m on the southern Amazonian floodplain in the Department of Madre de Dios (Map 47) (MacQuarrie 1992). The park includes the entire watershed of the Manu River and part of the catchment area of the Alto Madre de Dios River. Manu NP covers c.15,328 km², with roughly half in the pre-Andean subregion of Amazonia (below 500 m) where this site description is focused.
Most of the Manu River floodplain, including the Cocha Cashu field station, is at c. 400 m in elevation. The soil is among the most fertile in the tropics, judging from the density of animals and the growth rate of trees (Foster 1990a). Research in the park has been done mostly in the floodplain of the Manu River, especially at Cocha Cashu Biological Station (11°54'S, 71°22'W).
The Cocha Cashu study area is c. 10 km². In the area around the station the average annual temperature is 24°C and rainfall c. 2000 mm. Most of the rainfall occurs between November and May, while June through October normally receives less than 100 mm, though the year-to-year variation in the intensity and duration of the dry season is considerable (Terborgh 1990).
The Manu River floodplain is mostly covered by evergreen tropical forest, although a few species lose their leaves during the June-October dry season. One of the unique features of this almost pristine region is that the dynamic successional processes that characterize the vegetation of lowland Amazonia are preserved intact. While only a small fraction of the region is covered by obviously early successional vegetation, the entire floodplain may be eroded and redeposited every 500-1000 years (Terborgh 1990). Thus most of the floodplain forest, including the physiognomically most cathedral-like forest around the Cocha Cashu field station, may represent long-term vegetational succession (Gentry and Terborgh 1990). The Manu River area is one of very few places where the habitat mosaic of beaches, oxbow lakes and various forest types that result from these riverine processes can be observed intact, and their effects on the maintenance of species richness evaluated (Terborgh 1983, 1990; Foster 1990b).
Palms are an especially characteristic element of Manu park's vegetation. Three of the five commonest tree species in the mature floodplain forest are palms, and the palms together constitute c. one-sixth of stems with 10 cm or more dbh in this forest (Gentry and Terborgh 1990). Lianas are also very prevalent in the mature forest at Cocha Cashu - 79 lianas 2.5 cm or more in diameter representing 43 species were found in a 0.1-ha sample (Gentry 1985). Another distinctive physiognomic aspect of the vegetation of the rich-soil floodplain forest is the prevalence of strangling figs (Ficus). Many more fully developed stranglers are represented in a 1-ha tree plot at Cocha Cashu than in similar plots elsewhere in Amazonia (Gentry and Terborgh 1990). Some are truly massive, simultaneously strangling several host trees, and the gaps between their root columns can be so large that there are trails passing through these boles.
The Upper Amazonian rain forest represented by Manu is one of the most species-rich forest types in the world, and one of the only remaining regions of the rich-soil forests that originally characterized much of the eastern Andean forelands (Gentry and Ortiz-S. 1993). The species diversity of this region is generally greater than in most of Central Amazonia, and only slightly less than in the completely aseasonal forest farther north around Iquitos (CPD Site SA9). Although many new plant species have been discovered in Manu NP, it is not known to what extent they reflect local endemism rather than inadequate collection elsewhere.
In many ways the rich-soil area of Manu park is floristically more similar to southern Central America than the geographically nearer poor-soil areas of Amazonia (Gentry 1985). Several species previously known only from Central America and northernmost South America have been found. Presumably they represent part of a band of distinctive rich-soil flora that once extended along the base of the Andean/Amazonian interface. There are also a number of unanticipated and unexplained disjunctions - e.g. Clytostoma campanulatum was known only from the São Paulo region of Brazil.
Manu NP as a whole has at least 3000 vascular plant species, with the lowlands below 500 m having a documented flora of 1856 species in 751 genera of 130 families (Foster 1990a). The documented vascular flora of the Cocha Cashu area on recent alluvial soils is 1370 species belonging to 637 genera of 119 families. Leguminosae is the most important family, with over 90 species found in the floodplain-forest flora and over 140 species for the entire Manu River flora. However, the legumes constitute only 8% of the species; a dozen other families have 30 or more species, which is a typical familial composition for lowland Amazonia: Moraceae, Rubiaceae, Orchidaceae, Acanthaceae, Sapindaceae, Bignoniaceae, Araceae, Myrtaceae, Piperaceae, Sapotaceae and Solanaceae. Among the trees predominate Leguminosae, Moraceae, Sapotaceae and Lauraceae (Foster 1990a).
The largest genus is Ficus, which has its neotropical record with 35 species in the floodplain forest near the Cocha Cashu station. Inga, Piper and Pouteria have over 20 species; the largest liana genus is Paullinia with 19 species. The large numbers of species in genera such as Ficus, Inga, Piper, Pouteria and Paullinia are typical of neotropical forests on relatively rich soils. An interesting floristic peculiarity is the predominance of shrub species - the 375 shrub species known from the Manu floodplain constitute a quarter of the entire local flora.
The region includes nearly pure stands of mature Cedrela odorata (Spanish cedar) in successional forests on intermediate-age river terraces and has scattered large individuals of Swietenia macrophylla (bigleaf mahogany) in the floodplain forest. These have traditionally been perhaps the two most important Amazonian timber species, but they have been severely over-harvested, and today are usually encountered only rarely elsewhere. The now unique single-species stands of Cedrela are especially interesting, as they probably indicate that the well-known problem of Hypsipyla budworm attack on mahogany plantations is due more to their inappropriate placement on poor soils than to their density of planting.
A number of commercially important or potentially important fruit-tree species are very common in the Manu River floodplain forests (as well as other pre-Andean rich-soil forests). Quararibea cordata ("sapote") and Theobroma cacao (cacao) are among the ten commonest tree species at Cocha Cashu. Other frequently found tree species in genera with edible fruits include several palms (e.g. Astrocaryum), Pouteria, Annona, Inga and Diospyros. The forests of the rich-soil Upper Amazonian region represented by Manu NP probably include a disproportionate number of the general region's economically important plants, and they are exceptionally important to maintain germplasm for future programmes of genetic improvement (Gentry 1985; Phillips and Gentry 1993).
Social and environmental values
Between 300-500 Amerindians are believed to inhabit the Manu park region; they are isolated and have little contact with outsiders. The tribal groups represented are the Amahuaca, Machiguenga, Piro and Yaminahua (Baird 1984).
Cocha Cashu Biological Station was founded in 1969-1970, initially to facilitate investigation of the black caiman (Melanosuchus niger), South America's largest and commercially most valuable crocodilian. The station is one of the few research sites in the neotropics to offer an undisturbed ecosystem with a full complement of both top predators and their prey (Terborgh 1990). In the lowlands, the diversity of animal species includes 13 species of primates, giant armadillo, giant anteater, Amazon and giant otters, jaguar, ocelot, black and spectacled caimans and river turtles. Over 550 species of birds have been identified (Robinson and Terborgh 1990).
The Cocha Cashu field station enables scientists, students and managers to gain new insights on how an intact tropical forest ecosystem functions. More than 200 publications have been based on research at Cocha Cashu. Some processes can only be studied under near-pristine conditions in large intact forests, such as complex interactions involving successional dynamics over hundreds of years (Foster 1990b), seasonal changes in vertebrate foraging behaviours (Terborgh 1983) and the existence of keystone plant species that limit a forest's carrying capacity at critical times of the year (Terborgh 1986).
For many large vertebrate species, as well as such over-exploited plant species as in Cedrela and Swietenia, Manu NP provides one of the last conservation strongholds. Manu NP probably includes more species than any other conservation reserve in the world. Due to the vast area and altitudinal range within this important reserve, three Endemic Bird Areas (EBAs) are represented. The South-east Peruvian lowlands EBA (B30) is home to 15 restricted-range bird species, which inhabit the humid lowland forest up to c. 400m; the Eastern Andean foothills of Peru EBA (B29) is centred between 600-2200m, with 11 restricted-range species inhabiting humid forest; and the High Peruvian Andes EBA (B27), from 1800-4300m, has 30 restricted-range birds occurring in the more semi-humid and arid vegetation. Three (primarily poorly known) threatened bird species occur at the lower altitudes in this region; no less than 12 such species inhabit the more degraded High Peruvian Andes EBA.
The environment of the lowlands of Manu park owes its almost pristine quality to its location in the remote south-eastern corner of Peru. Cuzco, the nearest population centre, satisfies its need for food and wood from nearer sources. Larger markets (Lima and Arequipa) are 4-5 days away from the Manu region. Only the most valuable products, principally such prime hardwoods as Cedrela, Swietenia and Cedrelinga, can justify the high costs of transport.
The retention of large predators and high primate densities gives Manu NP a unique tourist potential. Ecotourism has recently been carried out around the park's fringes. Tourist camps exist within cultural and reserved zones adjacent to the park. Groom, Podolsky and Munn (1991) have considered this activity beneficial to the local economies; long-term effects on the indigenous populations and the wild animals are unknown.
According to Terborgh (1990), the short-term factors most likely to influence the development of south-eastern Peru are the possible discovery of mineral deposits and the price of petroleum. Various attempts to explore for oil or build a road through Manu NP have been blocked thus far. The greatest recent threat to the park's integrity has been a severe cutback in the number of park guards and its infrastructure.
Manu National Park was established in 1973 covering 15,328 km², and in 1977 an area encompassing 18,812 km² was declared a Biosphere Reserve under UNESCO's Man and the Biosphere Programme. Manu NP is widely perceived as Peru's premier park. Public attention combined with significant financial support have made protection and management more effective for Manu NP than Peru's other conservation areas. Since 1970, the nearly constant presence of scientists at Cocha Cashu Biological Station has had a positive effect on the park's management. However, if more support for park guards and infrastructure is not forthcoming, the positive status may change radically. Moreover, the national economy will need to improve for long-term conservation to be secure.
Map 47. Manu Biosphere Reserve, Peru (CPD Site SA11)
Baird, V. (1984). Tropical treasure under threat - bid to save Peru's natural heritage. Lima Times, 5 October. Pp. 6-7.
Foster, R.B. (1990a). The floristic composition of the Rio Manu floodplain forest. In Gentry, A.H. (ed.), Four neotropical rainforests. Yale University Press, New Haven. Pp. 99-111.
Foster, R.B. (1990b). Long-term change in the successional forest community of the Rio Manu floodplain. In Gentry, A.H. (ed.), Four neotropical rainforests. Yale University Press, New Haven. Pp. 565-572.
Gentry, A.H. (1985). Algunos resultados preliminares de estudios botánicos en el Parque Nacional del Manu. In Ríos, M.A. (ed.), Reporte Manu. Centro de Datos para la Conservación, Universidad Agraria, La Molina, Peru. Pp. 2/1-2/22.
Gentry, A.H. and Ortiz-S., R. (1993). Patrones de composición florística en la Amazonia peruana. In Kalliola, R., Puhakka, M. and Danjoy, W. (eds), Amazonia peruana vegetación húmeda tropical en el llano subandino. Proyecto Amazonia Universidad de Turku (PAUT) and Oficina Nacional de Evaluación de Recursos Naturales (ONERN). Jyväskylä, Finland. Pp. 155-166.
Gentry, A.H. and Terborgh, J. (1990). Composition and dynamics of the Cocha Cashu "mature" floodplain forest. In Gentry, A.H. (ed.), Four neotropical rainforests. Yale University Press, New Haven. Pp. 542-564.
Groom, M.J., Podolsky, R.D. and Munn, C.A. (1991). Tourism as a sustained use of wildlife: a case study of Madre de Dios, southeastern Peru. In Robinson, J.G. and Redford, K.H. (eds), Neotropical wildlife use and conservation. University of Chicago Press, Chicago and London. Pp. 393-412.
MacQuarrie, K. (1992). El paraíso amazónico del Perú: Manu, parque nacional y reserva de la biosfera / Peru's Amazonian Eden: Manu National Park and Biosphere Reserve. Francis O. Patthey e Hijos, Barcelona, Spain. 320 pp.
Phillips, O. and Gentry, A.H. (1993). The useful plants of Tambopata, Peru II: additional hypothesis testing in quantitative ethnobotany. Econ. Bot. 47: 33-43.
Robinson, S.K. and Terborgh, J. (1990). Bird communities of the Cocha Cashu Biological Station in Amazonian Peru. In Gentry, A.H. (ed.), Four neotropical rainforests. Yale University Press, New Haven. Pp. 199-216.
Terborgh, J. (1983). Five new world primates: a study in comparative ecology. Princeton University Press, Princeton, New Jersey. 260 pp.
Terborgh, J. (1986). Keystone plant resources in the tropical forest. In Soulé, M.E. (ed.), Conservation biology: the science of scarcity and diversity. Sinauer Associates, Sunderland, Massachusetts, U.S.A. Pp. 330-344.
Terborgh, J. (1990). An overview of research at Cocha Cashu Biological Station. In Gentry, A.H. (ed.), Four neotropical rainforests. Yale University Press, New Haven. Pp. 48-59.
This Data Sheet was written by the late Dr Alwyn H. Gentry.
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