The text that follows is a PREPRINT.

 

Please cite as:

 

Fearnside, P.M. 2001. South American natural ecosystems, Status of. pp. 345-359 In: S.A. Levin (ed.) Encyclopedia of Biodiversity, Vol. 5. Academic Press, San Diego, California, U.S.A.

 

Copyright: Academic Press

 

The original publication is available from  Academic Press, San Diego, California, U.S.A.

 

 

 

ECOSYSTEMS OF SOUTH AMERICA: STATUS AND THREATS

 

 

                        Philip M. Fearnside

                        Department of Ecology

                        National Institute for Research

                            in the Amazon (INPA)

                        Av. André Araújo, 1756

                        C.P. 478

                        69011-970 Manaus, Amazonas

                        BRAZIL

 

                        Fax: 55-92-642-8909

 

                        Tel: 55-92-643-1822

 

                        e-mail pmfearn@inpa.gov.br

 

Contribution for: S.A. Levin (ed.) Encyclopedia of Biodiversity. Academic Press, San Diego, California.

 

                   30 Sept. 1999

                   27 Nov. 1999

                   17 dec. 1999

ECOSYSTEMS OF SOUTH AMERICA: STATUS AND THREATS

 

 

 

 

Philip M. Fearnside

National Institute for Research in the Amazon (INPA), Manaus, Brazil

 

I.   ORIGINAL EXTENT OF TERRESTRIAL ECOSYSTEMS

II.  PRESENT EXTENT OF TERRESTRIAL ECOSYSTEMS

III. HUMAN USE OF CONVERTED AREAS

IV.  HUMAN USE OF REMAINING NATURAL HABITATS

V.   THREATS TO REMAINING NATURAL HABITATS

VI.  STATUS OF PROTECTED AREAS

VII. PRIORITIES FOR CONSERVATION

 

              GLOSSARY

 

Ecosystem: A set of interacting living and nonliving components in a defined geographic space. Ecosystems include both plant and animal communities and the soil, water and other physical elements of their environment.

 

Bioregion: One of six biogeographic divisions of South America consisting of contiguous ecoregions. Bioregions are delimited to better address the biogeographic distinctiveness of ecoregions.

 

Ecoregion: A geographically distinct assemblage of natural communities that share a large majority of their species and ecological dynamics, share similar environmental conditions, and interact ecologically in ways that are critical for their long-term persistence.

 

Major Ecosystem Type: Groups of ecoregions that share minimum area requirements for conservation, response characteristics to major disturbance, and similar levels of beta diversity (i.e., the rate of species turnover with distance).

 

Major Habitat Type: Groups of ecoregions that have similar general structure, climatic regimes, major ecological processes, beta diversity, and flora and fauna with similar guild structures and life histories.

 

The term “ecoregion,” as used in this article, refers to “natural” ecological systems, or terrestrial and aquatic areas as they were when Europeans first arrived in the New World. The original extent of natural ecoregions is presented, grouped by bioregion, major habitat type and major ecosystem type. The definitions of these terms, given in the glossary above, are taken from Dinerstein et al. (1995); the rating codes are given in the footnotes to the table. Indications of the extent of remaining natural ecosystems, the threats to their continued existence, and the status of protected areas are discussed, together with priorities for conservation.

 

I.   ORIGINAL EXTENT OF TERRESTRIAL ECOSYSTEMS

 

Ecosystems can be classified in many ways, making the number of categories vary widely depending on the use intended. Here, the system adopted by Dinerstein et al. (1995) is used. This divides the continent into 95 terrestrial “ecoregions,” exclusive of mangroves. These are grouped into four “major ecosystem types:” tropical broadleaf forests, conifer/temperate broadleaf forests, grasslands/savannas/shrublands, and xeric formations. Within each of these categories are varying numbers of “major habitat types,” such as tropical moist broadleaf forests. These are further divided into nine “bioregions” Amazonian tropical moist forests, for example, is a bioregion.

 

The 95 ecoregions, with their hierarchical groupings, are presented in Table I. Also included are the ratings for conservation status, biological distinctiveness and biodiversity priority derived by Dinerstein et al. (1995). This study made a systematic survey of the status of natural ecosystems in Latin America and the Caribbean (LAC) and applied a uniform methodology to assigning priorities to these ecosystems for conservation efforts. The work was done for the United States Agency for International Development (USAID) by the WWF-US Biodiversity Support Program (BSP). The document is based on three workshops, plus consultations with relevant organizations and individual experts (the list of contributors contains 178 names).

 

                   [Table I here]

 

The classification system is hierarchical, starting with four "major ecosystem types" (eg. Tropical Broadleaf Forests), which are divided into 10 "major habitat types" (eg. Tropical Moist Broadleaf Forests). These are crossed with six bioregions (eg. Amazonia) and divided into 95 ecoregions (eg. Rondônia/Mato Grosso moist forests). The system allows the priority of some ecoregions to be promoted upward based on uniqueness and regional representation, even if indicators of diversity and vulnerability are not so high.

 

The effort was unusual in emphasizing protection of areas with high beta diversity (a measure of the turnover of species along ecological gradients), as well as the more commonly used alpha diversity (species diversity within a habitat). In the case of mangroves, the diversity assessed is ecosystem diversity, including aquatic animal life. This avoids mangroves receiving the unjustly low diversity ratings that tend to result when assessments are restrained to terrestrial organisms, especially trees.

 

Although the ecoregions identified in Table I refer to “natural” (pre-Colombian) ecosystems, it should be emphasized that these had already been subject to millenia of influence by indigenous peoples prior to the arrival of Europeans. This influence continues today, together with much more rapid alterations from such activities as deforestation and logging done by non-indigenous residents. “South America” is taken to include the three Guianas (different from usage by the Food and Agriculture Organization of the United Nations-FAO) and to exclude Panama (however, in the case of ecoregions that extend into Panama, the area estimates in Table 1 include the Panamanian portions). The ecoregions are mapped in Figure 1. The ecoregion numbering corresponds to Table 1, and also to the report by Dinerstein et al. (1995); the numbering presented here is not continuous, since the report also includes ecoregions in Mexico, Central America and the Caribbean. Extensive bibliographic material on the delimitation of the ecoregions and on the state of knowledge about them can be found in Dinerstein et al. (1995).

 

                   [Figure 1 here]

 

Mangroves occur along the coasts of Brazil, the three Guianas, Venezuela, Colombia, Ecuador and northern Peru. Dinerstein et al. (1995) divide them into five complexes: Pacific South America, Continental Caribbean, Amazon-Orinoco-Maranhão, Northeast Brazil and Southeast Brazil. Each complex is further subdivided into 2-5 units, corresponding to distinct segments of coastline. Mangroves are essential to maintaining populations and ecological processes in surrounding marine, freshwater and terrestrial ecosystems.

 

II.  PRESENT EXTENT OF TERRESTRIAL ECOSYSTEMS

 

Unfortunately, information is not available on the present extent of each of the 95 ecoregions listed in Table I. Information on the extent of tropical forests in approximately 1990 is available from the FAO Tropical Forest Resources Survey (FAO, 1993). Non-tropical areas are covered by a variety of national surveys (Harcourt and Sayer, 1996). These data are tabulated by country in Table II. National data are important because decisions regarding land-use policies and conservation are taken at the national level – not at the levels of bioregions or ecosystem types. Over half of the South American continent is represented by a single country: Brazil (Fig. 2).

 

              [Table II and Figure 2 here]

 

An idea of the extent of existing ecosystems can be gained from measurements of land cover in 1988 made using 1 ´ 1 km-resolution data from the AVHRR sensor on the NOAA satellite series (Stone et al., 1994). These are given in Figure 3 and are tabulated in Table III.

 

              [Figure 3 and Table III here]

 

It should be emphasized that many ecosystems can be heavily disturbed by logging and other activities without the change being evident on satellite imagery. This is true for LANDSAT-TM imagery (30 ´ 30-m resolution) used for deforestation estimates in Brazil, and the limitations are much greater for 1 ´ 1-km AVHRR data.

 

Brazil is the country with the most extensive satellite information on forest cover and its loss. Unfortunately, information on non-forest vegetation types such as cerrado is much less complete. Considerable confusion arises between the FAO (1993) classification and others such as the one adopted here because FAO classifies cerrado, caatinga and chaco as “forests.”

 

Brazil’s Legal Amazon region originally had 4 million km2 of forests, the rest being cerrado and other types of savannas. Agricultural advance was slow until recent decades because of human diseases (especially yellow fever and malaria), infertile soil and vast distances to markets. These barriers have progressively crumbled, although a range of limiting factors restricts the extent and the duration over which many uses of deforested areas can be maintained (Fearnside, 1997a). Deforestation in the region has been predominantly for cattle pasture, with critical contributions to the motivations for the transformation coming from the role of clearing as a means of establishing land tenure and in allowing land to be held and sold for speculative purposes (Fearnside, 1993).

 

The Atlantic forests of Brazil (ecoregions 54 and 55) have been almost completely (>95%) destroyed, mainly for agriculture, silviculture and real-estate development. Most of what remains of this extraordinarily rich ecosystem is in protected areas, but unprotected areas continue in rapid retreat. These forests are recognized as major “hotspots” of biodiversity (Heywood and Watson, 1995; Stotz et al., 1996).

 

In Andean countries, clearing by small farmers has predominated in driving deforestation, in contrast to the predominant role of medium and large cattle ranchers in Brazil. Migration from densely populated areas in the Andean highlands (altiplano) has led to settlement in lowland forests areas, with consequent upsurges in clearing (eg., Rudel and Horowitz, 1993).

 

Savanna ecosystems have suffered heavy human pressure. The pampas of Argentina, and the Uruguayan savannas of Uruguay and southern Brazil (ecoregions 120 and 121) have largely been converted to agriculture. The Brazilian cerrado, originally covering 2 million km2, is the largest ecoregion in South America, as well as holding the largest number of species of any of the world’s savannas. The cerrado was largely intact until the mid-1970s. Clearing, especially for soybeans and planted pasture, reduced the cerrado to 65% of its original area by 1993 according to LANDSAT imagery interpreted by Brazil’s National Institute for Space Research (INPE). The advance of clearing has proceeded at an accelerating pace, speeded by infrastructure projects and an array of government subsidies.

 

The temperate and coniferous forests of the Southern Cone have been under severe pressure from logging. These forests are usually logged by clearcutting in a manner similar to their counterparts in the North American temperate zone. This contrasts with the “selective” logging (highgrading for a few species) that characterizes timber extraction from the diverse forests of the tropical region.

 

III. HUMAN USE OF CONVERTED AREAS

 

Conversion of natural ecosystems to agroecosystems and secondary forests creates landscapes that maintain biodiversity to varying degrees. “Shifting cultivation” as practiced by indigenous peoples and by traditional non-indigenous residents (caboclos) in Amazonian forests maintains a substantial part of the original biodiversity. This contrasts with the effect of the vast expanses of cattle pasture that have replaced this, either directly or following a phase of use in pioneer agriculture by small farmers who have recently arrived from other places.

 

In densely settled areas along the coast of Brazil and in the southern portions of the country, agricultural use has gone through a series of “cycles,” such as sugarcane and coffee. The productivity of many areas has been damaged by soil erosion and other forms of degradation. Cattle pasture is often the land use replacing these crops. Since the 1970s, plantation silviculture (which now covers over 70,000 km2) and soybeans (130,000 km2) have made large advances.

 

In Argentina and Uruguay, cattle ranching and wheat and rice farming are major land uses. Natural vegetation is better represented in areas with little agricultural potential, such as mountain and polar areas and arid and semiarid zones.

 

IV.  HUMAN USE OF REMAINING NATURAL HABITATS

 

Areas that remain under natural vegetation cover, rather than being converted to other land uses through clearing, are also subject to human use and alteration. Selective logging in tropical forests, for example, leaves much of the basic structure of the ecosystem intact, but also can lead to significant changes that can set in motion a sequence of events leading to complete destruction of the ecosystem. Logging leaves a substantial amount of dead biomass in the forest, including the crowns and stumps of harvested trees and all of the biomass of the many additional trees that are killed by damage sustained during the logging process. Openings created in the canopy allow sunlight and heat to penetrate to the forest floor, drying out the fuel bed more quickly than in unlogged forests. Climatic variations such as those provoked by the El Niño phenomenon make logged forests especially susceptible to entry of fires. Ample opportunities for fires are provided as fields are burned to prepare land for planting and as cattle pastures are burned to control invading weeds. The fires burn slowly through the understory, charring the bases of trees as they go. Many of these trees then die, leading to a positive-feedback process whereby more dead biomass and canopy openings are provided and subsequent fires begin with greater ease, killing still more trees. This can degrade the entire forest within a few years (Nepstad et al., 1999).

 

Tropical forests are also used for “extractivism,” or the collection of non-timber forest products (NTFPs) such as rubber and Brazilnuts. This does relatively little damage to the forest, although extractivists do have an impact through hunting and through clearing for subsistence crops. The extractivist population can also play a protective role in defending the forest against encroachment by more aggressive actors such as ranchers and loggers. This is the basis of the extractive reserve system in Brazil (see Anderson, 1990).

 

Savannas are often grazed by cattle without cutting trees. Cerrado (ecoregion 114), “lavrado” or Guianan savannas (ecoregion 111) the Pantanal wetlands (ecoregion 133) and the llanos of Venezuela (ecoregion 110) are among the savannas often used in this way. Increasing fire frequency, virtually all a result of human-initiated burning, can lead to shifts in species composition and to a drain of nutrients.

 

Aquatic ecosystems are traditionally exploited by fisheries. This alters the relative abundance of the species present. Use of watercourses as recipients for sewage and other pollutants also affects aquatic life in many ways.

 

V.   THREATS TO REMAINING NATURAL HABITATS

 

A. Terrestrial Ecosystems

 

1. Deforestation

 

Deforestation is the dominant transformation of forested ecosystems that threatens biodiversity. In Brazil, which holds most of the continent’s remaining forests, ranching is the dominant use for land once deforested. In the 1990s, soybeans began to enter forested regions, representing a new force in this process (they had already been a major factor in transformation of the cerrado since the 1970s). The most important effect of soybeans is not loss of forest directly planted to the crop, but the extensive infrastructure of waterways, railways and highways that are built to transport soybeans and the inputs needed to grow them. The cycle of deforestation that has repeatedly occurred along Amazonian highways can be expected to accompany these new access routes.

 

Population growth is a fundamental contributor to deforestation and other forms of natural habitat loss. In recent years, however, the redistribution of population through migration that has overshadowed the impact of absolute growth in population size. These include migrations from the semi-arid Northeast of Brazil to Amazonia, from Paraná to Rondônia, from the highlands of Bolivia, Peru and Ecuador to the Amazonian lowlands and, in the case of Ecuador, to the Pacific lowlands as well.

 

2. Logging and Charcoal Manufacture

 

Logging is an increasingly important factor in Amazonia, and the catalytic role of this activity in increasing the flammability of the logged forest gives it potential impact far beyond its direct damage. So far, logging in Brazil has been dominated by domestic demand for sawnwood, plywood and particle board, which is almost entirely supplied from tropical forests rather than from silvicultural plantations plantations (which produce wood for pulp and, to a lesser extent, charcoal). However, global markets for tropical timber are presently dependent on supplies from Asian forests that will soon come to an end if current rates of exploitation continue. In the 1990s, Asian logging companies began buying land and/or obtaining concessions in such countries as Brazil, Guyana and Suriname, and pressure from global timber markets can be expected to increase in the future. Asian loggers are also the principal forces in clearcutting the Valdivian and Nothofagus forests of Chile (ecoregions 88 and 89).

 

In eastern Amazonia, demand for charcoal for pig-iron smelting in the Carajás area is a potential threat to forests. Carajás, with the world’s largest deposit of high-grade iron ore, is expected to be mined for 400 years at the present rate of exploitation. Wood from native forests is inherently cheaper as a source of biomass for charcoal production as compared to plantation-grown sources. Charcoal manufacture has an impact on the forest both through direct removals (including officially sanctioned forestry management systems) and by increasing the profitability of logging and deforestation (see Anderson, 1990)

.

Deforestation impacts are magnified by fragmentation and edge effects (Laurance and Bierregaard, 1997). This division of the remaining natural habitat into many small islands surrounded by cattle pastures or other highly modified land uses, together with forming edges with increased entry of light, wind and foreign organisms, result in many changes in the remaining natural ecosystems. Most of these changes are forms of degradation, such as greatly increased mortality in the trees that provide the dominant component of forest structure. Vine loads on trees near edges also increase, leading to further increase in mortality and susceptibility to windthrow.

 

3. Other Threats

 

Climate change represents a major long-term threat to many South American ecosystems. The Intergovernmental Panel on Climate Change (IPCC) has prepared detailed reviews of potential climatic impacts on South America in its 1998 Special Report on Regional Impacts (Chapter 6) and its 2000 Third Assessment Report (Working Group II, Chapter 14).

 

Removal of fauna through hunting is a virtually universal consequence of proximity of human settlements to natural habitats. The removal of fauna can affect seed dispersal, pollination, and other processes needed for maintaining plant and animal communities. Introduction of exotic species also represents a threat to natural ecosystems. Exotic species are a particularly severe problem in the Valdivian and Nothofagus forests of Chile (ecoregions 88 and 89).

 

Mangrove ecosystems are subject to some unique threats. Shrimp culture in mangrove areas has had severe impacts on the coast of Ecuador. Mangroves in Maranhão have been subject to pressure for charcoal manufacture. In São Paulo state mangroves have often suffered from oil spills, and are also losing ground to real-estate development. This has also affected restingas (ecoregions 176-178).

 

B. Aquatic Ecosystems

 

1. Dams

 

Hydroelectric dams have major impacts on river ecosystems by blocking fish migration, by eliminating rapids and replacing well oxygenated running water with reservoirs that usually have anoxic water in their lower layers. The composition of fish present changes radically, and undergoes a succession of changes as reservoirs age. Anoxic water released through the turbines severely reduce fish and freshwater shrimp productivity in the rivers downstream of the dams.

 

In Brazil, the 2010 Plan, released in 1987, listed over 300 dams for eventual construction in Brazil, independent of the expected date of completion. Of these, 65 dams were in the Amazon region. Economic difficulties have caused projected construction dates to be successively postponed, but the ultimate number of dams has not changed. Most contentious is the Babaquara Dam on the Xingu River, which would flood over 6000 km2 of forest, much of it in indigenous areas. This has been renamed the “Altamira Dam,” and appears in the current decennial plan for construction by 2013.

 

In Chile, the dams planned and under construction on the Bio-Bio River are expected to have major environmental impacts. The Ralco Dam is particularly contentious. In Uruguay, at least five major dams are planned for construction in the next few years.

 

2. Waterways

 

Industrial waterways, known as hidrovias in Brazil, greatly alter aquatic habitats. No less than seven waterways are under construction or planned for soybean transport on barges: the Paraguay-Paraná (Hidrovia do Pantanal), the Madeira River waterway, the Tocantins-Araguaia waterway, the Teles Pires-Tapajós waterway, the Capim River waterway, the Mamoré-Guaporé Waterway and the Rio Branco and Rio Negro-Orinoco Waterways. Waterway construction involves blasting rock obstructions, cutting sharp curves, and dredging sediment from the river beds. The Corumbá-Cáceres stretch of the Hidrovia do Pantanal, if built, would lower the water level in the Pantanal wetlands (ecoregion 133), threatening one of the world’s most renowned concentrations of wildlife.

 

3. Other Threats

 

Other threats to aquatic habitats include sedimentation from soil erosion and landslides. This is severe, for example, in rivers draining steep areas of former Atlantic forest in the coastal mountains of Brazil. Mining for gold, tin and diamonds in Amazonia can also inject large amounts of sediment into streams and rivers.

 

Destruction of varzea forest (ecoregion 33) in Amazonia can affect aquatic life through loss of important fish breeding areas and food sources for fruit- and seed-eating fish. Destruction of varzea lakes and overfishing represent additional threats.

 

VI.) STATUS OF PROTECTED AREAS

 

The choice and design of reserves depends on the financial costs and biodiversity benefits of different strategies. In Brazil, rapid creation of lightly protected "paper parks" has been a means of keeping ahead of the advance of barriers to establishment of new conservation units, but emphasis must eventually shift to better protection of existing reserves (Fearnside, 1999).

 

Creating reserves that include human occupants has a variety of pros and cons (Kramer et al., 1997). Although the effect of humans is not always benign, much larger areas can be brought under protection regimes if human occupants are included. Additional considerations apply to buffer zones around protected areas. A “fortress approach,” whereby uninhabited reserves are guarded against encroachment by a hostile population in the surrounding area, is believed to be unworkable as a means of protecting biodiversity, in addition to causing injustices for many of the human populations involved

 

VII. PRIORITIES FOR CONSERVATION

 

Indigenous peoples have the best record of maintaining forest, but negotiation with these peoples is essential in order to ensure maintenance of the large areas of forest they inhabit (Fearnside and Ferraz, 1995). The benefits of environmental services provided by the forest must accrue to those who maintain these forests. Development of mechanisms to capture the value of these services will be a key factor affecting the long-term prospects of natural ecosystems.

 

In the case of deforestation in Amazonia, a variety of measures could be taken immediately through government action, including changing land tenure establishment procedures so as not to reward deforestation, revoking remaining incentives, restricting road building and improvement, strengthening requirements for environmental impact statements for proposed development projects, and creating employment alternatives, and, in the case of Brazil, levying and collecting taxes that discourage land speculation. A key need is for a better-informed process of making decisions on building roads and other infrastructure such that the full array of impacts is taken into account.

 

Environmental services represent a major value of natural ecosystems, and mechanisms that convert the value of these services into monetary flows that benefit the people who maintain natural habitats could significantly influence future events in the region (Fearnside, 1997b). Environmental services of tropical forests include maintenance of biodiversity, carbon stocks and water cycling. The water cycling function, although very important for countries in the region, does not affect other continents as the first two services do. At present, avoiding global warming by keeping carbon out of the atmosphere represents a service for which monetary flows are much more likely to result from international negotiations. Activities under the United Nations Framework Convention on Climate Change (UN-FCCC) are at a much more advanced stage of negotiation than is the case either for the Biodiversity Convention or for the “Non-Binding Statement of Principles” and possible future convention on forests.

 

In the case of carbon, major decisions regarding credits for tropical forest maintenance are likely to be taken at the sixth Conference of the Parties (COP-6) to the Kyoto Protocol, at the end of 2000 or early in 2001. This will be after the IPCC Special Report on Land-Use Change and Forestry (SR-LUCF) has been released in May 2000. Regardless of what is decided at COP-6, global warming is a permanent consideration that can be expected to receive increasing weight in decision making. The threats to natural ecosystems in South America are many, and recognition of the multiple environmental services provided by them is a key factor in insuring that substantial areas of each of these ecosystems continue to exist, thereby maintaining their biodiversity.


ACKNOWLEDGMENTS

     I thank Eric Dinerstein and the World Bank for permission to publish Figure 1 and Table I, and Tom Stone and the American Society for Photogrametry and Remote Sensing for permission to publish Figure 3 and Table II. Brazil's National Council of Scientific and Technological Development (CNPq AI 523980/96-5) and National Institute for Research in the Amazon (INPA PPI 1-3160) provided financial support. S.V. Wilson and two anonymous reviewers made helpful comments on the manuscript.

 

BIBLIOGRAPHY

 

Anderson, A.B. (ed.) (1990). Alternatives to Deforestation: Towards Sustainable Use of the Amazon Rain Forest. Columbia University Press, New York.

 

Dinerstein, E., Olson, D.M.; Graham, D.J.; Webster, A.L.; Primm, S.A.; Bookbinder, M.P., and Ledec, G. (1995). A Conservation Assessment of the Terrestrial Ecoregions of Latin America and the Caribbean. The World Bank, Washington, DC.

 

FAO (Food and Agriculture Organization of the United Nations). (1993). Forest Resources Assessment 1990: Tropical Countries. (FAO Forestry Paper 112). FAO, Rome, Italy.

 

Fearnside, P.M. (1993). Deforestation in Brazilian Amazonia: The effect of population and land tenure. Ambio 22(8), 537-545.

 

Fearnside, P.M. (1997a). Limiting factors for development of agriculture and ranching in Brazilian Amazonia. Revista Brasileira de Biologia 57(4), 531-549.

 

Fearnside, P.M. (1997b). Environmental services as a strategy for sustainable development in rural Amazonia. Ecological Economics 20(1), 53-70.

 

Fearnside, P.M. (1999). Biodiversity as an environmental service in Brazil's Amazonian forests: Risks, value and conservation. Environmental Conservation 26(4)(in press).

 

Fearnside, P.M., and Ferraz, J. (1995). A conservation gap analysis of Brazil's Amazonian vegetation. Conservation Biology 9(5), 1134-1147.

 

Harcourt, C.S., and Sayer, J.A. (eds.) (1996). The Conservation Atlas of Tropical Forests: The Americas. Simon & Schuster, New York, U.S.A. 335 pp.

 

Heywood, V.H. and R.T. Watson (eds.). 1995. Global Biodiversity Assessment. Cambridge University Press, Cambridge, U.K. 1140 pp.

 

Kramer, R., van Schaik, C. and Johnson, J. (Eds.) (1997). Last Stand: Protected Areas and the Defense of Tropical Biodiversity. Oxford University Press, Oxford, U.K. 197 pp.

 

Laurance, W.F., and Bierregaard, R.O. (Eds.) (1997). Tropical Forest Remnants: Ecology, Management, and Conservation of Fragmented Communities. University of Chicago Press, Chicago, Illinois.

 

Nepstad, D.C; Moreira, A.G., and Alencar, A.A. (1999). Flames in the Rain Forest: Origins, Impacts and Alternatives to Amazonian Fire. Pilot Program to Conserve the Brazilian Rain Forest, Brasilia, Brazil

 

Rudel, T.K., and Horowitz, B. (1993). Tropical Deforestation: Small Farmers and Land Clearing in the Ecuadorian Amazon. Columbia University Press, New York.

 

Stone, T.A.; Schlesinger, P.; Houghton, R.A, and Woodwell, G.M.. (1994). A map of the vegetation of South America based on satellite imagery. Photogrammetric Engineering and Remote Sensing 60(5), 541-551.

 

Stotz, D.F.; Fitzpatrick, J.W.; Parker III, T.A., and Moskovitz, D.K. (1996). Neotropical Birds: Ecology and Conservation. University of Chicago Press, Chicago, Illinois.

 

Figure Legends

 

Figure 1 – Ecoregions for pre-Colombian vegetation of South America. Numbers correspond to Table I. (Adapted from: Dinerstein et al., 1995)

 

Figure 2 – Locations mentioned in the text.

 

Figure 3 – Extent of land-cover types in 1988 based on 1 ´ 1 km-resolution AVHRR imagery (source: http://www.whrc.org; see also: Stone et al., 1994).

Table I: Terrestrial Ecoregions of South America

 

 

 

 

 

 

 

 

 

 

Major Ecosystem type

Major Habitat type

Bioregion

Ecoregion Name

Ecoregion No.

Countries

Original area (km2)

Conservation status

Biological distinctiveness

Bidiversity priority

TROPICAL BROADLEAF FORESTS

 

Tropical Moist Broadleaf Forests

 

 

Orinoco Tropical Moist Forests

 

 

 

 

Cordillera La Costa montane forests

17

Venezuela

13,481

3

2

I

 

 

 

Orinoco Delta swamp forests

18

Venezuela, Guyana

31,698

4

3

III

 

 

 

Guianan Highlands moist forests

20

Venezuela, Brazil, Guyana

248,018

5

2

III

 

 

 

Tepuis

21

Venezuela, Brazil, Guyana, Suriname, Colombia

49,157

5

1

II

 

 

 

Napo moist forests

22

Peru, Ecuador, Colombia

369,847

4

1

I

 

 

Amazonian Tropical Moist Forests

 

 

 

 

 

 

 

Macarena montane forests

23

Colombia

2,366

3

2

I

 

 

 

Japurá/Negro moist forests

24

Colombia, Venezuela, Brazil

718,551

5

1

II

 

 

 

Uatumã moist forests

25

Brazil, Venezuela, Guyana

288,128

4

3

III

 

 

 

Amapá moist forests

26

Brazil, Suriname

195,120

4

3

III

 

 

 

Guianan moist forests

27

Veneauela, Guyana, Suriname, Brazil, French Guiana

457,017

4

3

III

 

 

 

Paramaribo swamp forests

28

Suriname

7,760

3

3

III

 

 

 

Ucayali moist forests

29

Brazil, Peru

173,527

2

1

I

 

 

 

Western Amazonian swamp forests

30

Peru, Colombia

8,315

4

1

I

 

 

 

Southwestern Amazonian moist forests

31

Brazil, Peru, Bolivia

534,316

4

1

I

 

 

 

Juruá moist forests

32

Brazil

361,055

5

2

III

 

 

 

Várzea forests

33

Brazil, Peru, Colombia

193,129

3

1

I

 

 

 

Purús/Madeira moist forests

34

Brazil

561,765

4

4

IV

 

 

 

Rondônia/Mato Grosso moist forests

35

Brazil, Bolivia

645,089

3

2

II

 

 

 

Beni swamp and gallery forests

36

Bolivia

31,329

4

4

IV

 

 

 

Tapajós/Xingu moist forests

37

Brazil

630,905

3

4

IV

 

 

 

Tocantins moist forests

38

Brazil

279,419

2

4

III

 

 

Northern Andean Tropical Moist Forests

 

 

 

 

 

 

 

Chocó/Darién moist forests

39

Colombia, Panama, Ecuador

82,079

3

1

I

 

 

 

Eastern Panamanian montane forests

40

Panama, Colombia

2,905

2

1

I

 

 

 

Northwestern Andean montane forests

41

Colombia, Ecuador

52,937

2

1

I

 

 

 

Western Ecuador moist forests

42

Ecuador, Colombia

40,218

1

2

I

 

 

 

Cauca Valley montane forests

43

Colombia

32,412

1

1

I

 

 

 

Magdalena Valley montane forests

44

Colombia

49,322

1

1

I

 

 

 

Magdalena/Urabá moist forests

45

Colombia

73,660

2

3

II

 

 

 

Cordillera Oriental montane forests

46

Colombia

66,712

3

1

I

 

 

 

Eastern Cordillera Real montane forests

47

Ecuador, Colombia, Peru

84,442

3

1

I

 

 

 

Santa Marta montane forests

48

Colombia

4,707

3

2

I

 

 

 

Venezuelan Andes montane forests

49

Venezuela, Colombia

16,638

2

1

I

 

 

 

Catatumbo moist forests

50

Venezuela, Colombia

21,813

1

4

III

 

 

Central Andean Tropical Moist Forests

 

 

 

 

 

 

 

Peruvian Yungas

51

Peru

188,735

2

1

I

 

 

 

Bolivian Yungas

52

Bolivia, Argentina

72,517

2

2

I

 

 

 

Andean Yungas

53

Argentina, Bolivia

55,457

3

3

III

 

 

Eastern South American Tropical Moist Forests

 

 

 

 

 

 

 

Brazilian Coastal Atlantic forests

54

Brazil

233,266

1

1

I

 

 

 

Brazilian Interior Atlantic forests

55

Brazil

803,908

2

2

I

 

Tropical Dry Broadleaf Forests

 

 

 

 

 

 

Orinoco Tropical Dry Forests

 

 

 

 

 

 

 

Llanos dry forests

74

Venezuela

44,177

2

4

III

 

 

Amazonian Tropical Dry Forests

 

 

 

 

 

 

 

Bolivian Lowland dry forests

76

Bolivia, Brazil

156,814

1

1

I

 

 

Northern Andean Tropical Dry Forests

 

 

 

 

 

 

 

Cauca Valley dry forests

77

Colombia

5,130

1

4

III

 

 

 

Magdalena Valley dry forests

78

Colombia

13,837

1

4

III

 

 

 

Patía Valley dry forests

79

Colombia

1,291

1

4

III

 

 

 

Sinú Valley dry forests

80

Colombia

55,473

1

4

III

 

 

 

Ecuadorian dry forests

81

Ecuador

22,271

1

1

I

 

 

 

Tumbes/Piura dry forests

82

Ecuador, Peru

64,588

2

1

I

 

 

 

Marañon dry forests

83

Peru

14,921

2

3

II

 

 

 

Maracaibo dry forests

84

Venezuela

31,471

2

4

III

 

 

 

Lara/Falcón dry forests

85

Venezuela

16,178

2

4

III

 

 

Central Andean Tropical Dry Forests

 

 

 

 

 

 

 

Bolivian montane dry forests

86

Bolivia

39,368

1

3

II

CONIFER/TEMPERATE BROADLEAF FORESTS

 

 

 

Temperate Forests

 

 

 

Southern South American Temperate Forests

 

 

 

 

 

 

 

Chilean winter-rain forests

87

Chile

24,937

2

2

I

 

 

 

Valdivian temperate forests

88

Chile, Argentina

166,248

3

1

I

 

 

 

Subpollar Nothofagus forests

89

Chile, Argentina

141,120

3

3

III

 

Tropical and Subtropical Coniferous Forests

 

 

 

 

 

Eastern South American Tropical and Subtropical Coniferous Forests

 

 

 

Brazilian Araucaria forests

105

Brazil, Argentina

206,459

1

3

II

GRASSLANDS/SAVANNAS/SHRUBLANDS

 

 

Grasslands, Savannas and Shrublands

 

 

 

 

 

Orinoco Grasslands, Savannas and Shrublands

 

 

 

 

Llanos

110

Venezuela, Colombia

355,112

4

3

III

 

 

Amazonian Grasslands, Savannas and Shrublands

 

 

 

 

Guianan savannas

111

Suriname, Guyana, Brazil, Venezuela

128,375

4

3

III

 

 

 

Amazonian savannas

112

Brazil, Colombia, Venezuela

120,124

4

3

III

 

 

 

Beni savannas

113

Bolivia

165,445

2

3

II

 

 

Eastern South American Grasslands, Savannas and Shrublands

 

 

 

 

Cerrado

114

Brazil, Paraguay, Bolivia

1,982,249

3

1

I

 

 

 

Chaco savannas

115

Argentina, Paraguay, Bolivia, Brazil

611,053

3

2

I

 

 

 

Humid Chaco

116

Argentina, Paraguay, Uruguay, Brazil

474,340

3

4

IV

 

 

 

Córdoba montane savannas

117

Argentina

55,798

3

4

IV

 

 

Southern South American Grasslands, Savannas and Shrublands

 

 

 

 

Argentine Monte

118

Argentina

197,710

4

3

III

 

 

 

Argentine Espinal

119

Argentina

207,054

4

3

III

 

 

 

Pampas

120

Argentina

426,577

2

3

III

 

 

 

Uruguayan savannas

121

Uruguay, Brazil, Argentina

336,846

3

3

III

 

Flooded Grasslands

 

 

 

 

Orinoco Flooded Grasslands

 

 

 

 

Orinoco wetlands

128

Venezuela

6,403

4

3

III

 

 

Amazonian Flooded Grasslands

 

 

 

 

Western Amazonian flooded grasslands

129

Peru, Bolivia,

10,111

4

3

III

 

 

 

Eastern Amazonian flooded grasslands

130

Brazil

69,533

3

3

III

 

 

 

São Luis flooded grasslands

131

Brazil

1,681

2

4

III

 

 

Northern Andean Flooded Graslands

 

 

 

 

 

Guayaquil flooded grassland

132

Ecuador

3,617

2

3

II

 

 

Eastern South American  Flooded Grasslands

 

 

 

 

 

Pantanal

133

Brazil, Bolivia, Paraguay

140,927

3

1

I

 

 

 

Paraná flooded savannas

134

Argentina

36,452

2

3

II

 

Montane Grasslands

 

 

 

Northen Andean Montane Grasslands

 

 

 

 

 

Santa Marta paramo

137

Colombia

1,329

3

1

I

 

 

 

Cordillera de Mérida paramo

138

Venezuela

3,518

4

1

I

 

 

 

Northern Andean paramo

139

Ecuador

58,806

3

1

I

 

 

Central Andean Montane Grasslands

 

 

 

 

 

Cordillera Central paramo

140

Peru, Ecuador

14,128

3

1

I

 

 

 

Central Andean puna

141

Bolivia, Argentina, Peru, Chile

183,868

3

2

I

 

 

 

Central Andean wet puna

142

Chile

188,911

3

2

I

 

 

 

Central Andean dry puna

143

Argentina, Bolivia, Chile

232,958

3

2

I

 

 

Southern South American Montane Grasslands

 

 

 

 

 

Southern Andean steppe

144

Argentina, Chile

198,643

4

4

IV

 

 

 

Patagonian steppe

145

Argentina, Chile

474,757

3

2

I

 

 

 

Patagonian grasslands

146

Argentina, Chile

59,585

3

3

III

XERIC FORMATIONS

 

 

 

Mediterranean Scrub

 

 

 

Central Andean Mediteranean Scrub

 

 

 

 

 

Chilean matorral

148

Chile

141,643

2

1

I

 

Deserts and Xeric Shrublands

 

 

 

Orinoco Deserts and Xeric Shrublans

 

 

 

 

 

La Costa xeric Shrublands

168

Venezuela

64,379

2

4

III

 

 

 

Arayua and Paría xeric scrub

169

Venezuela

5,424

2

3

II

 

 

Northern Andean Deserts and Xeric Shrublands

 

 

 

 

 

Galapagos Islands xeric scrub

170

Ecuador

9,122

3

1

1

 

 

 

Guajira/Barranquilla xeric scrub

171

Colombia, Venezuela

32,404

2

3

II

 

 

 

Paraguaná xeric scrub

172

Venezuela

15,987

2

3

II

 

 

Central Andean Deserts and Xeric Shrublands

 

 

 

 

 

Sechura desert

173

Peru, Chile

189,928

3

3

III

 

 

 

Atacama desert

174

Chile

103,841

3

3

III

 

 

Eastern South American Deserts and Xeric Shrublands

 

 

 

 

 

Caatinga

175

Brazil

752,606

3

3

III

 

Restingas

 

 

 

Northern Andean Restingas

 

 

 

 

 

Paranaguá restingas

176

Venezuela

15,987

2

3

II

 

 

Amazonian Restingas

 

 

 

 

 

Northeastern Brazil restingas

177

Brazil

10,248

1

1

I

 

 

Eastern South American Restingas

 

 

 

 

 

Brazilian  Atlantic Coast restinga

178

Brazil

8,740

1

1

I

 

 

 

 

Data source: Dinerstein et al. (1995)

 

 

 

Conservation status codes: 1=critical, 2=endangered, 3=vulnerable, 4=relatively stable, 5=relatively intact

 

 

 

Biological distinctiveness codes: 1=globally outstanding, 2=regionally outstanding, 3=bioregionally outstanding, 4=locally important

 

 

 

Biodiversity priority codes: I=highest priority at regional scale, II=high priority at regional scale, III=moderate priority at regional scale, IV=important at national scale

 

 

 

Table II: Area of Tropical Forest Present in 1990 (km2)(a)

 

 

 

 

 

 

 

 

 

 

 

Tropical

rain

forests

Moist

decid-

uous

forest

Dry

decid-

uous

forest(b)

Very

dry

forest

Desert

Hill

and

montane

forest

All

forests(b)

Bolivia

 

0

355,820

73,460

0

40

63,850

493,170

Brazil

 

2,915,970

1,970,820

288,630

0

0

435,650

5,611,070

Colombia

 

474,550

41,010

180

0

0

24,900

540,640

Ecuador

 

71,500

16,690

440

0

0

31,000

119,620

French Guiana

79,930

30

0

0

0

0

79,970

Guyana

 

133,370

31,670

0

0

0

19,120

184,160

Paraguay

 

0

60,370

67,940

0

0

270

128,590

Peru

 

403,580

122,990

190

2,690

1,840

147,770

679,060

Suriname

 

114,400

33,280

0

0

0

0

147,680

Venezuela

196,020

154,650

2,220

1

0

103,900

456,910

 

 

 

 

 

 

 

 

 

Total

 

4,389,320

2,787,330

433,060

2,691

1,880

826,460

8,440,870

 

 

 

 

 

 

 

 

 

(a) Data source: FAO (1993).

(b) Includes cerrado, caatinga and chaco.

 

 

Table III: Land-Cover in South America in 1988

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Closed

 

 

 

 

 

 

Degraded

Scrub­

 

 

 

 

 

 

Tropical

Recently

 

Degraded

 

Degraded

Savanna,

Savanna,

lands,

Desert,

 

Snow,

 

 

 

Moist

Degraded

Closed

Closed

Wood-

Wood-

Grass-

Grass-

Shrub-

Bare

 

Rock,

 

 

 

Forest

TMF

Forest

Forest

lands

lands

lands

lands

lands

Soil

Water

Ice

Other

Total

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Argentina

1.2

0.0

96.8

0.6

645.4

15.7

755.4

232.8

894.a

37.9

34.0

31.4

35.7

2,779.8

Bolivia

323.5

12,7

409.2

24.6

345.1

102.2

87.7

86.2

4.8

16.5

11.9

0.1

1.1

1,089.4

Brazil

3,522.3

519.7

3,686.0

1,692.2

1,555.9

330.0

740.0

179.4

0.0

0.0

80.9

0.0

124.0

8,388.5

Chile

0.0

0.0

134.1

29.1

75.2

29.8

101.1

14.0

86.9

186.8

7.0

16.6

3.8

684.5

Colombia

581.6

5.4

622.5

11.4

116.3

14.5

255.5

64.0

0.0

0.0

3.1

0.0

22.8

1,110.1

Ecuador

115.5

1.7

121.0

1.7

33.7

4.3

41.9

13.3

3.2

2.5

0.6

0.0

0.8

223.1

French Guiana

78.8

0.0

79.8

2.4

0.6

0.0

0.2

0.0

0.0

0.0

0.1

0.0

1.0

84.1

Guyana

159.4

2.0

171.6

2.4

5.4

0.3

18.4

1.5

0.0

0.0

1.2

0.0

3.7

204.3

Paraguay

0.3

0.0

8.9

0.2

209.1

50.7

104.0

26.5

0.0

0.0

0.6

0.0

1.1

401.1

Peru

620.8

19.1

654.7

19.1

88.0

78.8

139.0

97.4

64.3

88.0

8.3

0.7

5.6

1,244.1

Suriname

126.0

2.5

128.5

10.0

0.5

0.3

1.2

0.4

0.0

0.0

1.1

0.0

3.3

145.2

Uruguay

1.4

0.0

2.1

0.0

0.9

0.0

154.1

11.0

0.0

0.0

3.0

0.0

5.9

177.0

Venezuela

379.1

0.2

415.5

9.9

33.9

40.2

243.3

82.0

27.2

0.0

11.4

0.0

8.4

871.8

Unclassified

 

 

 

 

 

 

 

 

 

 

 

 

 

313.0

Total

5,909.9

563.4

6,530.7

1,803.7

3,109.8

666.9

2,642.0

808.5

1,080.6

331.7

163.2

48.9

2t7.2

17,716.1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Continent

33.4%

3..2%

36.9%

10.2%

17.6%

3.8%

14.9%

4.6%

6.1%

1.9%

0.9%

0.3%

1.2%

100.0%

Category

 

 

8.7%

 

21.6%

 

17.7%

 

23.4%

 

 

 

 

 

 

N.B. All values in thousands of km2 or percent.

"TMF" includes Tropical Moist, Semi-deciduous and Gallery Forests

"Grasslands" includes those seasonally flooded

"Closed forest" includes TMF, Montane forests, Cool and Temperate Deciduous Forests and Tropical Seasonal Forests "Degraded grasslands" includes Agriculture

"Desert, Bare Soil" includes inland Salt Marsh Communities

"Other" includes wet vegetation and mangroves

Source:  Stone et al., 1994.

 

 

Fig. 1 part 1

Fig. 1 part 2

 

Fig. 2