The realm also includes temperate southern South America. In contrast, the NeotropicalFloristic Kingdom excludes southernmost South America, which instead is placed in theAntarctic kingdom.
The Neotropic is delimited by similarities infauna orflora. Its fauna and flora are distinct from theNearctic realm (which includes most of North America) because of the long separation of the two continents. The formation of theIsthmus of Panama joined the two continents two to three million years ago, precipitating theGreat American Interchange, an importantbiogeographical event.
The Neotropical realm and its subdivisions
The Neotropic includes moretropical rainforest (tropical and subtropical moist broadleaf forests) than any other realm, extending from southern Mexico through Central America and northern South America to southern Brazil, including the vastAmazon rainforest. These rainforest ecoregions are one of the most important reserves ofbiodiversity on Earth. These rainforests are also home to a diverse array ofindigenous peoples, who to varying degrees persist in their autonomous and traditional cultures andsubsistence within this environment. The number of these peoples who are as yet relatively untouched by external influences continues to decline significantly, however, along with the near-exponential expansion ofurbanization, roads,pastoralism andforest industries which encroach on their customary lands and environment. Nevertheless, amidst these declining circumstances this vast "reservoir" of human diversity continues to survive, albeit much depleted. In South America alone, some 350–400indigenous languages and dialects are still living (down from an estimated 1,500 at the time offirst European contact), in about 37 distinctlanguage families and a further number ofunclassified andisolate languages. Many of these languages and their cultures are also endangered. Accordingly,conservation in the Neotropical realm is a hot political concern, and raises many arguments about development versus indigenous versus ecological rights and access to or ownership ofnatural resources.
TheWorld Wide Fund for Nature (WWF) subdivides the realm intobioregions, defined as "geographic clusters of ecoregions that may span several habitat types, but have strong biogeographic affinities, particularly at taxonomic levels higher than the species level (genus, family)."
The Central Andes lie between the gulfs ofGuayaquil andPenas and thus encompass southern Ecuador, Chile, Peru, western Bolivia, and northwest and western Argentina.[2]
Eastern South America includes theCaatingaxeric shrublands of northeastern Brazil, the broadCerrado grasslands and savannas of theBrazilian Plateau, and thePantanal andChaco grasslands. The diverseAtlantic forests of eastern Brazil are separated from the forests of Amazonia by the Caatinga and Cerrado, and are home to a distinct flora and fauna.
North of the Gulf of Guayaquil in Ecuador and Colombia, a series of accreted oceanic terranes (discrete allochthonous fragments) have developed that constitute the Baudo, or Coastal, Mountains and the Cordillera Occidental.[3]
The Orinoco is a region of humid forested broadleaf forest and wetland primarily comprising thedrainage basin for theOrinoco River and other adjacent lowland forested areas. This region includes most of Venezuela and parts of Colombia, as well asTrinidad and Tobago.
South America was originally part of the supercontinent ofGondwana, which included Africa, Australia, India, New Zealand, and Antarctica, and the Neotropic shares many plant and animal lineages with these other continents, includingmarsupial mammals and theAntarctic flora.
After the final breakup of the Gondwana about 110 million years ago, South America was separated from Africa and drifted north and west. 66 million years ago, theCretaceous–Paleogene extinction event altered local flora and fauna.[4][5] Much later, about two to three million years ago, South America was joined with North America by the formation of theIsthmus of Panama, which allowed a biotic exchange between the two continents, theGreat American Interchange. South American species like the ancestors of theVirginia opossum (Didelphis virginiana) and thearmadillo moved into North America, and North Americans like the ancestors of South America'scamelids, including thellama (Lama glama), moved south. The long-term effect of the exchange was the extinction of many South American species, mostly by outcompetition by northern species.
The Neotropical realm has 63 endemicfish families and subfamilies, which is more than any other realm.[6]Neotropical fishes include more than 5,700 species, and represent at least 66 distinct lineages in continental freshwaters (Albert and Reis, 2011). The well-knownred-bellied piranha is endemic to the Neotropic realm, occupying a larger geographic area than any other piranha species. Somefish groups originally unique to the Neotropics include:
The outlined ecoregions of the Neotropical realm, each of a colored biome. Note that this realm has 11 of14 biomes, or major habitat types, as defined by Olson & Dinerstein, et al. (2001).[12]
^van der Sleen, Peter, and James S. Albert, eds. (2018)Field Guide to the Fishes of the Amazon, Orinoco, and Guianas. Princeton University Press, 2017.ISBN9780691170749
^Simberloff, Daniel (March–April 1984). "The Next Mass Extinction".Garden.8 (2):4–5.
^Тахтаджян А. Л. Флористические области Земли / Академия наук СССР. Ботанический институт им. В. Л. Комарова. — Л.: Наука, Ленинградское отделение, 1978. — 247 с. — 4000 экз.DjVu,Google Books.
^Takhtajan, A. (1986).Floristic Regions of the World. (translated by T.J. Crovello & A. Cronquist). University of California Press, Berkeley,PDF,DjVu.
^Olson, D. M., Dinerstein, E., Wikramanayake, E. D., Burgess, N. D., Powell, G. V. N., Underwood, E. C., D'Amico, J. A., Itoua, I., Strand, H. E., Morrison, J. C., Loucks, C. J., Allnutt, T. F., Ricketts, T. H., Kura, Y., Lamoreux, J. F., Wettengel, W. W., Hedao, P., Kassem, K. R. (2001). Terrestrial ecoregions of the world: a new map of life on Earth.Bioscience 51(11):933–938,[1]Archived 2012-09-17 at theWayback Machine.
Bequaert, Joseph C. "An Introductory Study of Polistes in the United States and Canada with Descriptions of Some New North and South American Forms (Hymenoptera; Vespidæ)".Journal of the New York Entomological Society 48.1 (1940): 1-31.
Cox, C. B.; P. D. Moore (1985).Biogeography: An Ecological and Evolutionary Approach (Fourth Edition). Blackwell Scientific Publications, Oxford.
Olson, D. M., B. Chernoff, G. Burgess, I. Davidson, P. Canevari, E. Dinerstein, G. Castro, V. Morisset, R. Abell, and E. Toledo. 1997.Freshwater biodiversity of Latin America and the Caribbean: a conservation assessment. Draft report. World Wildlife Fund-U.S., Wetlands International, Biodiversity Support Program, and United States Agency for International Development, Washington, D.C.
Reis, R. E., S. O. Kullander, and C. J. Ferraris Jr. 2003.Check List of the Freshwater Fishes of South and Central America. Edipucrs, Porto Alegre. 729 pp.
