Note: This website is no longer being updated and is being maintained for archive purposes by the Department of Botany, National Museum of Natural History, Smithsonian Institution. Please see About the Project for further details.
MOUNTAIN RANGES OF RIO DE JANEIRO
The State of Rio de Janeiro has much topographic diversity (Domingues 1976). The mountainous region is formed by the Serra do Mar and inland Serra da Mantiqueira, consisting of crystalline rocks of the Brazilian Shield.
The Serra do Mar often presents a steep slope, both abrupt and continuous, in crossing the state from west-south-west to east-north-east, from the border with the State of São Paulo to the municipality Campos (Map 51). The range emerges directly from the ocean; from this point northward, it distances itself from the coastline but remains parallel, separated by alluvial plains. In the north it finally is transformed into a series of peaks and isolated hills. The relief is very pronounced, with elevations from sea-level to c. 2300 m. The highest points are in the area of Teresópolis; outstanding are Pedra do Sino (2263 m), Pedra Acu (2230 m) and Pico Dedo de Deus (1695 m).
The Serra da Mantiqueira rises farther inland to the west, where the states of Rio de Janeiro and São Paulo meet the State of Minas Gerais, and continues from west-south-west to the north-east in Minas Gerais. In Rio de Janeiro this mountain range often is very dissected, having its more accentuated topography in the south, where the peaks of Itatiaia reach nearly 2800 m.
Between the escarpments of the Serra da Mantiqueira and Serra do Mar is the valley of the Paraíba do Sul River, which is much lower than the crests of the two ranges. Another important topographic feature is the lowlands along the coast ("baixadas"). Their width (to 25 km) varies greatly, as the proximity of the foothills of the Serra do Mar to the sea is variable.
The only major river is the Paraíba do Sul, which leaves the Serra do Mar sensu lato at the north-eastern end of Serra Grande and flows into the ocean. It drains part of the Serra da Mantiqueira and the Serra do Mar's north-western slope. The crest of the Serra do Mar is a watershed boundary that directs shorter south-eastern rivers to the ocean.
The climate of the state is very variable because of the elevation and orientation of the mountain ranges. The coastal lowlands, Serra do Mar, Paraíba do Sul Valley, and Serra da Mantiqueira are all oriented west-south-west to east-north-east and have dramatically different elevations. The frequent arrivals of cool fronts of polar origin and polar anticyclones also are important factors affecting the regional climate. These are all significant influences that result in an uneven distribution of rainfall in Rio de Janeiro.
Summer (December-March) is warmer and in general wetter than winter (June-September). In the lowlands the climate is predominantly hot and humid, with the mean annual temperature c. 24°-26°C and the mean annual rainfall usually a little above 1000 mm. In the Paraíba valley, the rainfall is c. 1500 mm and the temperature also between 24°-26°C. In the mountainous regions the rainfall is high (2000-2500 mm) with no dry months and the temperature normally c. 18°-19°C (Nimer 1989; Domingues 1976).
The evergreen vegetation of these mountain ranges shows a diversified physiognomy, shaped mainly by the topographic and climatic factors. There is considerable variation in height, stratification and floristic composition. The vegetation can be classified in three types which, although distinct, often show intermediate characteristics: low-mountain forest, high-mountain forest and high-altitude fields.
1. Low-mountain forest
2. High-mountain forest
Above 1400 m and extending to 1600-1800 m is a more open, upland forest formation with smaller trees. The soil is very shallow and there are huge uncovered rocks. The trees are represented by Miconia spp., Rapanea spp., Lamanonia speciosa, Weinmannia spp. and Drimys brasiliensis. The liana Fuchsia regia is well represented. Foliaceous and filamentous lichens appear in large quantities on the tree branches.
3. Open fields ("campos de altitude")
The flora of the mountain ranges of Rio de Janeiro has received considerable study since at least the beginning of the 19th century. Although a high number of taxa from the region were covered in Flora Brasiliensis, data were very incomplete. The first intensive floristic surveys were during the 1940s in the Serra dos Orgãos (Davis 1945; Veloso 1945; Rizzini 1953-1954) and in the Serra da Mantiqueira, particularly at Itatiaia (Brade 1956). These data, added to those recently obtained in other regions (JBRJ 1990, 1992; Guedes 1989; Martinelli 1989) are beginning to thoroughly demonstrate the great diversity and high level of endemism in the flora of Rio de Janeiro.
About 5000-6000 species of vascular plants occur, with 70-80% endemic to the tropical Atlantic coast. The most important families in numbers of species are Myrtaceae, Lauraceae, Leguminosae, Rubiaceae, Orchidaceae, Compositae, Euphorbiaceae and Sapotaceae. There is an urgent need for floristic inventories to build up precise knowledge about the distribution of the species.
Although data are still very incomplete, the State of Rio de Janeiro is considered one of the centres of endemism for the Atlantic Coast rain forest (Mori, Boom and Prance 1981). These centres are being correlated with possible areas of forest refugia in arid periods during the Pleistocene (Mori 1989).
The high-altitude fields also possess many endemics, including palaeoendemics. Species found within this unique flora very often are restricted to only one mountain ridge. Classical examples include species of Prepusa, Fuchsia, Tillandsia and Tibouchina, and the well-known amaryllid Worsleya rayneri (Martinelli 1984) and bamboo Glaziophyton mirabile.
The forest resources of the Atlantic coast were heavily exploited during the initial colonization of Brazil. Plants that were useful for a wide variety of purposes such as timber, medicinals and food were intensely exploited as commercially important products. In south-eastern Brazil these valuable species included Caesalpinia echinata (Brazil-wood) and many other hardwoods - Dalbergia nigra, Melanoxylum brauna, Mezilaurus navalium, Colubrina glandulosa and species of Ocotea, Nectandra, Aspidosperma and Tabebuia.
Despite the over-exploitation of the last 500 years, the forest plants on the mountain ranges of Rio de Janeiro still have great potential. Recent preliminary studies have shown that c. 35% of the vascular plants in this region have some economic value. This high percentage is even more significant when one considers that the areas covered with natural forest in Rio de Janeiro have been reduced to less than 15% of their former extent.
Social and environmental values
Forest preservation will protect watersheds in these mountains that provide water for many towns and cities (Domingues 1976). The forests occurring in the mountain ranges have an important role in preventing soil erosion, as they are located on lands where erosion susceptibility is moderate to severe, with slopes of 35° or higher ridges with slopes of 45°. These forests, while reducing damage to the roads and highways which are the economic link between Brazil's south-east and north-east, support the transportation of agricultural products of the mountains to the metropolitan region. Economic activities developed in the mountainous region of Rio de Janeiro are primarily directed toward production of legumes and horticultural products. There is also significant production of oranges, tangerines and bananas.
This is one of the most important regions of the world for biodiversity, holding a high number of endemic taxa, many of which are threatened because so little of their original habitats remains. Two very important Endemic Bird Areas (EBAs) are partially found here. The South-east Brazilian lowland to foothills EBA (B52) stretches along the coast from Rio Grande do Sul to north-eastern Brazil. Many of the 60 bird species comprising this EBA are confined to south-eastern Brazil; 38 occur in Rio de Janeiro State, 17 of which are threatened. The South-east Brazilian mountains EBA (B53) is centred on the Serra do Mar and Serra da Mantiqueira; 18 of the 20 species comprising this EBA occur in the Rio de Janeiro ranges.
The scenic beauty of the landscapes and the richness and endemism of the fauna and flora support ecological tourism in the region. Considering that the city of Rio de Janeiro is one of the main tourist attractions of Brazil, the preservation of the forest in this region is basic to development of tourist activities.
Scientific knowledge of the coastal rain forest is still very limited. There is an urgent necessity for research on composition, structure, function and conservation for this ecosystem. The remaining forest is of fundamental importance for preservation of the genetic diversity of the species. A programme of conservation must be planned and initiated, including an inventory of species and their uses, biological studies on those species with the most potential and creation of genetic reserves. Development of studies on sustainable uses of the species is urgently needed.
The absence of a policy promoting settlement of populations in the countryside and stimulating agricultural production, particularly in the State of Rio de Janeiro, has caused a great impact in the areas near large urban centres. Immigrants come in large numbers (mostly from the country's north-east) in search of a new better life in the south-east. Nowadays, informed about the difficulties of living in the city of Rio de Janeiro, they opt for settlement in the adjacent mountainous region, where they generally become unskilled labourers.
The proximity of the city of Rio, as well as the mild climate and exuberant scenery, are key ingredients for land speculation. Construction of summer villas in forested areas belonging to non-working farms is often an additional problem. These construction projects normally have no plan for the land occupation, nor have they conducted any studies of environmental impact, and they may worsen the risk of landslides from seasonal strong showers. Since many of these dwellings are illegally built above the maximum elevation permitted (to ensure preservation of water springs), shortage of water during the dry season is a common problem.
The current habitat loss and exploitation of forests in Rio de Janeiro are destructive practices which are drastically reducing the size and the number of the state's remaining natural areas. Destruction of the forest around some high-altitude granitic outcrops has made their vegetation susceptible to fire, which is made worse by invasion of the African grass Panicum maximum.
Some cases of selective exploitation of species rate mention. The extraction of palm heart from Euterpe edulis ("palmito") is a source of money for poor people living on hillsides, along the roads and highways. Collecting of ornamentals (e.g. bromeliads, orchids, Araceae) is also alarming. Pteridophytes too are threatened, particularly species of tree ferns of Cyathea (including Trichipteris) and Dicksonia sellowiana the popular "xaxim", which is now listed as a species threatened with extinction. These taxa are collected in order to supply the florists established in mountain towns and countless orchid fanciers.
In addition there is the threat of excessive timber extraction. Areas near the towns of Nova Friburgo, Teresópolis and Resende provide 32% of the total extracted timber of the state, much of which is fuelwood to supply brick factories in the foothills as well as bakeries in metropolitan Rio de Janeiro (SECPLAN 19901991). The great volume of timber that used to occur along the Atlantic coast has been consumed almost totally as charcoal, ignoring the potential of each species for devising the rational use of these resources.
Another important factor in the inadequate use of natural resources is the lack of an effective policy protecting the areas officially under conservation. Unlike Brazilian hydroelectric plants, which were built by federal acquisition of the lands to be inundated, the many preserves although legally created - are not adequately protected and do not effectively function because a large portion of their areas is privately owned.
In 1990 the government of the State of Rio de Janeiro decreed as preserved the remaining areas of Atlantic forest in the state. Thus Rio de Janeiro became the fourth state (1985, São Paulo and Paraná; 1990, Espírito Santo) to participate in preservation of the Serra do Mar sensu lato, promoting the conservation of a continuous forest (Collins 1990) with an area larger and under better protection than many others in the country. The demarcated area in Rio de Janeiro covers 6567 km², corresponding to 15.16% of the state's territory, with forest covering c. 5908 km². The parks, reserves, Ecological Stations and Environmental Protection Zones (Areas de Proteção Ambiental APAs) under the responsibility of federal or state governments total c. 3220 km² in c. 20 units.
The existence of large protected areas grouping parks and reserves, such as Bocaina (1100 km²), Itatiaia (300 km²), Tinguá (260 km²) and Serra dos Orgãos (115 km²), does not necessarily signify effective conservation of natural areas, because little is known about their floristic and faunistic composition. This paucity of knowledge limits management strategies and environmental education, and in consequence there is poor supervision of the reserve borders. Effective conservation of the areas of coastal forest, as well as the other areas with ecological value, is probably linked to acquiring the land, without which the endeavours may be in vain.
Map 51. Mountain Ranges of Rio de Janeiro, South-eastern Brazil (CPD Site SA15)
Brade, A.C. (1956). A flora do Parque Nacional de Itatiaia. Parque Nac. Itatiaia Bol. 5: 1-85.
Collins, M. (ed.) (1990). The last rain forests: a world conservation atlas. Oxford University Press, New York. 200 pp.
Davis, D.E. (1945). The annual life cycle of plants, mosquitoes, birds and mammals in two Brazilian forests. Ecol. Monogr. 15(3): 243-295.
Domingues, A.J.P. (1976). Estudo do relevo, hidrografia, clima e vegetação das regiões programa do estado do Rio de Janeiro. Bol. Geogr. 248: 5-73.
Guedes, R.R. (1989). Composição florística e estrutura de um trecho de mata perturbada de baixada no município de Magé, Rio de Janeiro. Arq. Jard. Bot. Rio de Janeiro 29: 155-200.
JBRJ (1990). Relatório anual do programa Mata Atlântica, Rio de Janeiro. Jardim Botânico do Rio de Janeiro (JBRJ), Rio de Janeiro. 220 pp.
JBRJ (1992). Relatório anual do programa Mata Atlântica, Rio de Janeiro. JBRJ, Rio de Janeiro. 73 pp.
Martinelli, G. (1984). Nota sobre Worsleya rayneri (J.D. Hooker) Traub & Moldenke, espécie ameaçada de extinção. Rodriguésia 36(58): 65-72.
Martinelli, G. (1989). Campos de altitude. Editora Index, Rio de Janeiro. 160 pp.
Mori, S.A. (1989). Eastern, extra-Amazonian Brazil. In Campbell, D.G. and Hammond, H.D. (eds), Floristic inventory of tropical countries: the status of plant systematics, collections, and vegetation, plus recommendations for the future. New York Botanical Garden, Bronx. Pp. 427-454.
Mori, S.A., Boom, B.M. and Prance, G.T. (1981). Distribution patterns and conservation of eastern Brazilian coastal forest tree species. Brittonia 33: 233-245.
Nimer, E. (1989). Climatologia do Brasil. Instituto Brasileiro de Geografia e Estatística (IBGE), Departamento de Recursos Naturais e Estudos Ambientais, Rio de Janeiro. 422 pp.
Rizzini, C.T. (1953-1954). Flora organensis. Lista preliminar dos cormophyta da Serra dos Orgãos. Arq. Jard. Bot. Rio de Janeiro 13: 117246.
SECPLAN (Secretaria de Planejamento e Controle) (1990-1991). Anuário estatístico do estado do Rio de Janeiro (1990/91), 7/8. Governo do Estado do Rio de Janeiro, Rio de Janeiro.
Veloso, H.P. (1945). As comunidades e as estações botânicas de Teresópolis, estado do Rio de Janeiro. Bol. Mus. Nac. Rio de Janeiro, Sér. Bot. 3: 195.
This Data Sheet was written by Rejan R. Guedes-Bruni and Haroldo C. de Lima (Jardim Botânico do Rio de Janeiro, Seção de Botânica Sistemática, Rua Pacheco Leo 915, 22460 Rio de Janeiro, RJ, Brazil).
Map information supplied by Pedro Marcilio da Silva Leite, IBGE.
North | Middle | South
CPD Home -
Botany Home Page | Smithsonian Home Page