The Neotropic region covers South America and Central America as far north as coastal Mexico and the Caribbean. The two dominant physical features of the region, the massive ridge of the Andes mountains and the vast Amazon river, have dramatic effects on the vegetation and plants.
The Neotropics has almost a third of the world’s total seed-bearing plants, almost 80,000. Deforestation, logging, and grazing animals have all contributed to the loss of some species, while others thrive in their surroundings.
If you want to know more about the plants of the Neotropic region, please read on.
The countries of Central and South America contain many biogeographic areas, from the very dry to the very wet. The climates range from tropical in the north, where the equator passes through the continent, to subarctic at the southern tip.
The long ridges of the Andes mountains run along almost the length of the Pacific coast, and this influences the climate and wildlife in seven countries. The Amazon river and its associated tributaries run through most of Brazil and parts of five other neotropical countries.
Away from the Andes and Amazonia, vast tracts of tropical grasslands (or savanna), and tropical deciduous forest, cover the hotter northern regions, giving way to treeless temperate grassland (the pampas) further south.
As the climate becomes cooler in southern Argentina, the pampas changes to a scrub of thorn and parched grasses, with the vegetation dwindling through Patagonia to the cold, windy wastes of Tierra del Fuego.
The eastern coast receives humid winds from the Atlantic Ocean, supplying rain to a strip of tropical forest that follows much of Brazil’s coast. Although no more than a few miles wide in places, this region supports rich flora and fauna.
The western coast from Ecuador to Santiago in Chile is almost a desert since the rain that comes from Amazonia to the northeast is extracted by the Andes and returned to the Amazon system.
Further south, prevailing winds from the Pacific Ocean bring moisture to support a temperate deciduous woodland until the bitter winters of the far south impose their own limitations on the landscape.
Within the Neotropic region are many distinctly different types of landscape. Each main type contains a number of variations, depending on latitude and geography, and in some places are quite unique habitats where plants have adapted perfectly.
Some of the endangered species of the region inhabit such places, while other more widely distributed species are threatened by large-scale alterations made by people.
The Neotropic region is divided into eight floristic regions: the Caribbean, Venezuela and Guiana, Amazon, South Brazilian, Andean, Juan Fernandez, Pampas, and Patagonian.
The first four of these are largely covered by rainforest, giving the Neotropics the greatest species diversity in the world.
Unlike its counterparts in Africa and Asia, the extensive area of tropical rainforest covering much of Brazil and adjacent counties in South America remained intact until the latter part of the twentieth century, when rapid destruction occurred.
The larger the rainforest, the greater the number of species that are likely to be found there. Rainforests can support a large number of species due to their climate. The Amazon rainforest has an estimated 80,000 species of seed-bearing plants, making up one-third of the world’s total.
To put this in context, the rainforests of Africa and Southeast Asia have about 30,000 seed-bearing plant species. Great Britain has about 1,800 seed-bearing plant species, about half of North and South Carolina combined.
Much of the Neotropic tropical rainforest is flat or rolling, and mountainous areas reach no higher than 1,200 meters (4,000 feet.)
Rainfall in these areas reaches 2-4 meters (80-160 inches) per year, and the temperature is relatively high year-round, usually around 24-26 C (75-79 F).
There is no regular seasonal change affecting the whole vegetation like there are in temperate parts of the world. While plants may lose their foliage on an annual basis, the timing of this varies from species to species, so flowering and fruiting occur year-round.
Forest trees are the structural component of the rainforest, forming the canopy of the forest. Many familiar, everyday woods as well as fine cabinet woods come from the Amazonian forests, including rubber and mahoganies.
Among the endangered trees of the Ecuadorian lowland rainforest is the Caoba Persea theobromifolia. Described in 1977, this tree is a relative of the Avocado and has commercially important lumber with properties similar to mahogany. However, the main cause of Caoba’s demise is the rapid conversion of forests to banana and oil palm plantations.
The rapid reduction of up to 70% has led it to be commercially extinct in parts of South America, El Salvador, and Costa Rica.
Color of the Rainforest
With so many species concentrated together in the rainforest, it is surprising that the forest floor has the same color as a beech or pine forest. In an undisturbed or primeval rainforest, not much light reaches the ground except in clearings where a tree has fallen.
Most of the color and much of the life and activity of tropical rainforest are concentrated in the canopy. The herbaceous plants, including gingers, ferns, grasses, and sedges, only occur where sufficient light penetrates the tree canopy.
These plants can become very large, often growing to 5 meters (16 feet) or more. Unlike the trees and herbaceous plants, the lianas, vines, and other climbers need external support. With the support of large trees, climbers can grow to 200 meters (650 feet) or more.
Some of the larger climbing palms and rattans are prominent examples of climbers exploited by humans. Dicliptera dodsonii, an orange-flowered vine of lowland forest, is a species threatened with extinction through forest conversion.
On tree trunks and branches, and on the climbers, grow the epiphytes, something we know as air plants. These are kept worldwide as houseplants.
Epiphytes are any plant that grows upon another plant or object for physical support. They have no attachment to the ground or other obvious nutrient sources but are not parasitic on the supporting plants.
It is likely this group which contains the greatest number of endangered or vulnerable plants. Among the epiphytes often collected for specialist growers around the world are the air plants or bromeliads.
Many of the 411 species of the genus Tillandsia are endangered through over-collecting. Glomeropitcairnia erectiflora is vulnerable in the cloud forests of Trinidad because of disturbance by visitors climbing to the summit of Mount Tucuche.
Many of the rainforest orchids are epiphytes, and these highly specialized plants occur in the greatest numbers in tropical rainforests. Ecuador boasts about 2,670 species out of a world total of about 25,000, while the whole of the USA only has approximately 200.
Andean Floristic Region
Much of western South America is included in the Andean floristic region. Traveling south from Colombia on the western side of the Andes, the tropical rainforest gives way to dry forest, then to Mediterranean-type vegetation, and eventually to the desert.
The desert has less than 2 millimeters (0.08 inch) of annual rainfall in the Atacama desert in Chile. Among the most vulnerable plants, there are the succulents, particularly the Chilean barrel cacti. Habitat destruction isn’t the main threat, but over-collecting for sale to plant lovers.
Chile is the longest country in the world, spanning some 4,000 kilometers (2,600 miles) from the Atacama desert to Tierra del Fuego and encompassing many vegetation types.
At latitudes greater than about 38 degrees south, the annual rainfall is higher than in tropical South America, the average often exceeding 5 meters (200 inches) per annum.
Chile does not include any tropical rainforest, but an equally valuable temperate rainforest has developed over thousands of years on the windward side of the Andes. Covering a much smaller area than its tropical equivalent, this unique forest is likely to be very vulnerable in the coming few decades.
The False Larch has been described by the Chileans as a cornerstone of their culture and civilization, from the cradle to the grave. Large tracts of native forest have been felled and is used in building and construction as well as in musical instruments.
The threat to this remarkable tree is heightened by its slow-growing, often taking up to 500 years to reach maturity. At least nine specimens, believed to be up to 4,000 years old, have already been removed.
The Monkey Puzzle is also threatened, specifically because of the central role it has played in the lives of the original inhabitants of the Andes, the Araucarian Indians.
Rare conifers such as the Chilean False Larch Fitzroya cupressoides, the tallest tree in chile, and the Monkey Puzzle Araucaria araucana are characteristic of the temperate rainforest.
They traditionally used the tree’s seeds as a source of food and also use it to make buttons and other artifacts to supplement their basic income. As a result, the Monkey Puzzle’s gene pool has been severely depleted.
Juan Fernandez Islands
Juan Fernandez is a small group of Pacific islands lying about 640 kilometers (400 miles) west of Santiago, Chile. They form a separate floristic region because they are even more isolated botanically than the Galapagos islands.
Their endemic flora includes about 98 flowering plants and 17 ferns, most of which are threatened by forest destruction caused by introduced grazing animals.
Crusoe’s Mayu-monte Sophora fernandeziana, scattered through the montane forests of Isla Robinson Crusoe, is described as vulnerable.
Another species of the same genus, Selkirk’s Mayu-monte Sophora masafuerana, is considered to be endangered. It occurs only on the neighboring Isla Alejandro Selkirk, where it is found on cliff ledges and in the forest covering the walls of deep canyons.
These two species are particularly important as they represent a vital link between other species of the genus found in Easter Island, New Zealand, Hawaii, and Chile.
Pampas and Patagonia
The floristic region described as Pampas covers a large area in temperate South America, including Uruguay, southeastern Brazil, western Argentina, and the Argentine pampas.
Large parts of this region have been modified by humans over many centuries, and cattle ranching maintains the area in a way comparable with the savannas of east Africa, where grazing by herds of large herbivores and natural fires prevent the growth of secondary forests.
The Patagonian region comprises Patagonia and Tierra del Fuego, the southern Andes, and the Falkland Islands. These areas have not suffered the population increases experienced in the tropical north, and the threats to the native flora and fauna are much less significant.
However, tourist development since the 1980s could have an adverse effect on the wildlife of the Falkland Islands. Felton’s Flower nearly became extinct in the wild, although it survives in cultivation close to its original locality on West Point Island.