SOUTH AMERICA

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Pierre Devillers and Jean Devillers-Terschuren. 1996. Habitats of South America. PHYSIS Data Base. Royal Belgian Institute of Natural Sciences. Last updated 1999.

This section of the PHYSIS database of the Royal Belgian Institute of Natural Sciences offers a framework to organise the habitats of the South American realm in an ordered sequence, according to the same methodology as that used for the CORINE Biotopes Habitats of the European Community typology (Devillers et al., 1991). The geographical area covered encompasses South America and its nearshore islands, Trinidad and Tobago, Margarita, Aruba, Curaçao, Bonaire, Los Roques, Blanquilla and associated islands, the Galapagos Islands, Malpelo Island, the Juan Fernandes Islands, the San Felix archipelago, Fernando de Noronha, South Trinidad and the Martin Vas islands, St. Peter and St. Paul rocks, Easter Island and Sala y Gomez.

World compatibility and homogeneity of treatment were insured by anchoring the main structure to three sets of references:

- a set of complete, single-source, summaries of the world's habitats, relevant to coherence of choices in habitat placement within the hierarchy, primarily Walter and Breckle (1991) Ökologie der Erde, Rieley and Page (1990) Ecology of plant communities, Huetz de Lemps (1994) Les paysages végétaux du globe, Archibold (1995) Ecology of world vegetation;

- a series of world-scale treatment of broad habitat types, ensuring homogeneity of treatment on the plane of a given upper-order habitat unit, primarily the series Ecosystems of the world, edited by D.W Goodall, and equivalent works for habitat groups not yet treated in the series, notably taken from the series Handbook of vegetation science, edited by H. Lieth (wetlands), or Springer-Verlag, Ecological studies (montane forests);

- four continent-wide descriptions of vegetation and habitats ensuring homogeneity along the other plane, that of geographical relations within South America, namely, Hueck (1978) Los bosques de Sud America, Cabrera and Willink (1980) Biogeografia de America Latina, Hueck and Seibert (1981) Vegetationskarte von Südamerika, Schnell (1987) La flore et la végétation de l'Amerique tropicale.

The general framework was completed by collection, analysis and organization of local references, including publications of restricted diffusion and unpublished technical reports, for all parts of the continent, to reach a uniform minimum level of resolution of habitat identification. The analysis was pursued to a higher level of resolution in three areas, Argentina, Venezuela and Chile, representative respectively of southern subtropical and temperate regions, of tropical forest and savanna belts, and of the Pacific deserts; all have an Andean component that spans the northern tropical, southern tropical and temperate Andes. For these areas, all currently recognized habitat types are explicitly included, whether the country is covered by a detailed vegetation map (Venezuela, Huber and Alarcon, 1988), by a vegetation unit list (Chile, Gajardo, 1994), or by an array of government conservation services and academic publications (Argentina). The same is true for regions within these countries covered by unified habitat lists (Corrientes, Carnevali, 1994), or by vegetation maps (Venezuelan Guiana, Huber, 1995). Recognition of elementary units by local users should thus be exempt of difficulties.

A total of more than 2600 habitat units were identified and described, including both collective and elementary units. Forest units represent 29% of the total, open shrub or grassland habitats 25%, deserts 8%, marine and saline habitats 15%, fresh water and marsh habitats 16%, anomalous habitats 7%. Among terrestrial habitats, tropical habitats account for 64%, temperate ones for 36%. The relatively large proportion of temperate habitats identified may appear anomalous in view of the proportionately small surface of the continent occupied by them and their relatively low biological diversity at the stational level. The balance probably, indeed, reflects, in part, a methodological bias linked to an uneven degree of knowledge, but also, certainly, the tendency of temperate habitats to single species dominance or oligarchic dominance, introducing a higher level of inter-station contrast at the level of perception at which the CORINE habitat typology is constructed, that of the ecological requirements of small vertebrates, invertebrates and vascular plants. Comparison of numbers of units per habitat class with their Palaearctic equivalents, corrected for the surfaces concerned, suggests an average level of resolution for South America of the order of 75% of that attained for Western and Central Europe, at least for the landcover-significant habitats of units 3 and 4. Further analysis of under-inventoried units is in progress.

An alarming number of South American habitat units are in a precarious conservation state, or reduced to an extremely small and often fragmented portion of their potential cover. This is particularly true of subtropical habitats, of dry woodland types, of mediterranean habitats, of coastal rain forests and of mountain-slope habitats, both in the main Andean chain and in isolated mountain ranges.

To consult the base click on the button below; once the opening page of the base presentation is reached, browsing through the hierarchy is achieved via the book icon in the upper left corner, a search function and a complete list of references are offered through buttons in the left column. To obtain further information on the PHYSIS methodology click on the left button at the bottom of the page you are presently in. To return to the PHYSIS presentation page click on the centre button. To return to the home page of the Section of Conservation Biology click on the right button.