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The Caatinga biome

Por: Denise Moraes

Mapa: Uol Educação

Mapa: Uol Educação

The caatinga biome is located in Northeast Brazil. It covers about 12% of the country’s territory, extending over large swaths of the states of Ceará, Piauí, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, Bahia, and also a part of northern Minas Gerais.

The climate in the caatinga is hot, with long dry seasons; rainfall has a major impact on the life of both animals and plants. It is not as biodiverse as other Brazilian biomes, like the Atlantic rainforest or the Amazon, but recent studies have uncovered a large number of endemic species—in other words, species found only in this region. Plantlife in the caatinga comprises scrub trees that remain dry and withered almost all year round.

Caracara*

Caracara*

Fauna

Most animals in the caatinga are nocturnal, so they don’t have to move around during the hottest time of day. There are many kinds of lizards: 47 species have been recorded to date, including the South American ground lizard and the whiptail lizard.

Snakes are also a common reptile, with 45 species identified so far. The tropical rattlesnake is one you can spot most often in the caatinga.

Some birds are typical caatinga residents, like the southern crested caracara, Picazuro pigeon, and white-napped jay.

 Lear

Lear's macaw**

Spix’s macaw (known in Portuguese as the ararinha azul) was formerly found in this biome but was last seen in nature in 2000; since then it has been placed on the list of extinct species by the Brazilian Institute for the Environment and Renewable Natural Resources (Ibama). 

The Lear's macaw is other bird listed as an endangered species, due to habitat loss, hunting and trapping for de aviary trade. It lives only in a small area in the interior northeast of Brazil.

Rock cavy***

Rock cavy***

Amphibians are abundant in the caatinga too. Among the most well known are the marine toad and the bullfrog (Rana edulis).

The caatinga is also home to many mammals. Living amidst the dry trees and rocky soil are jaguars, wildcats, capybaras, opossums, cavies, capuchin monkeys, and Brazilian brocket deer (veado catingueiro), an endangered species, just like Spix’s macaw.

 

Flora

When we hear the word caatinga, what comes to mind is an arid, dry environment with pale, withered trees nearly barren of leaves. Well, this really is how plantlife looks most of the year. But when rain does fall, the caatinga is transformed: the landscape turns green and flowers even blossom.

Photo: deltafrut/Flickr

Photo: deltafrut/Flickr

The flora of the caatinga is made up of xerophytes. These species have developed ways of surviving where rainfall is scarce and the humidity low. This biome has lots of stunted trees and bushes. Many species of its plants have thorns. In the case of cactuses, their leaves have evolved over time into spines so less water gets lost through transpiration.

Another way that plants keep from losing water is to drop their leaves during the dry season. This is why caatinga vegetation seems lifeless, lacking leaves and color, just a lot of dried-up, twisted stalks and trunks. But these plants aren’t really dead. They’re actually still alive, some using their well-developed root systems to reach water stored in the ground. Other species have developed roots that run across the ground, allowing them to absorb as much surface water as possible when the rains come. Other species have solved the problem in another way, by storing the water themselves—this is what cactuses do.

Mandacaru cactus****

Mandacaru cactus****

Cactuses are fine representatives of the caatinga but not the only ones. Even though the period of rains is brief, the caatinga has a variety of plant species, including the mandacaru cactus; the coroa-de-frade melon cactus; the xique-xique cactus; a jujube known as the juazeiro; umbuzeiros (Spondias tuberosa), which are sometimes called umbra trees in English; and a Brazilian peppertree known as the aroeira.

Soil

The soil is generally shallow and rich in minerals but poor in organic matter, since decomposition is hampered by intense heat and light all year round.

Chunks of rock are commonly found on the ground, lending the landscape a craggy appearance. It’s hard for rocky soil like this to store rainwater when it does fall.

The minerals found in the earth guarantee fertility in an environment that suffers from insufficient rain. This is why some dry regions can transform themselves so quickly during the few months when rain does fall, bursting out into green trees and grasses.

Photo: Sergio Sertão/Wikipedia

Photo: Sergio Sertão/Wikipedia

Topography

Two formations predominate in the caatinga: plateaus and large depressions. As you’ve already seen, pieces of rock are often found on the surface. This is often the case in higher areas as well. Many times when you look out across the plateaus of Northeast Brazil, you’ll see huge rocks perched atop them, looking like they might roll down at any minute. But don’t worry! You can wander the caatinga without concern. These rocks are a normal part of the topography of this biome.

The depressions of the caatinga are flat-lying areas generally lower than their surrounds, sometimes presenting small hills. The largest depressions in the caatinga are called the Sanfranciscan, Cearense, and Meio Norte.

Located in the states of Paraíba, Pernambuco, Rio Grande do Norte, and Alagoas, the Borborema plateau is a notable topographical feature, with altitudes averaging between 650 and 1000 meters (roughly 2,000-3,000 ft). These heights are surpassed in a few spots, like Jabre peak in Paraíba, which reaches 1,197 meters (3,972 ft), and Papagaio peak in Pernambuco, which stands 1,260 meters tall (4,133 ft).

The plateau forms a major obstacle for the moisture-laden clouds moving inland from the Atlantic Ocean. When the clouds come up against this giant wall, they condense to form rain on the eastern lowland side of the plateau, that is, the side towards the ocean. The clouds can’t get passed the Borborema plateau, which keeps rain from reaching the western, drought-ridden side. This dry side is part of the caatinga biome.

Water

Most of the rivers in the Brazilian caatinga are intermittent or temporary. This means they simply vanish during dry periods. Since rain is scarce in this biome throughout most of the year, the rivers born here remain dry for long periods of time.

São Francisco River*****

São Francisco River*****

Rivers whose sources lie elsewhere, like the São Francisco and the Parnaiba, are vital to life in the caatinga, since they cut through these hot dry lands on their way to the sea. These two rivers are so important in fact that they lend their names to two hydrographic basins that feed this region: the São Francisco River Basin and the Parnaiba River Basin. The Eastern-Northeast Coastal Basin is also found in this region.

People who live in the caatinga build wells, waterholes, and dams to get them through the dry seasons. Even so, they usually only reach salt water, unfit for human consumption.

Climate

The caatinga has a semi-arid climate, characterized by low humidity and low rainfall. Even though we mentioned this earlier, we want to stress this essential feature of the caatinga: rain doesn’t fall for very long periods of the year, with annual droughts of eight to nine months.

This unsteady climate affects watercourses, which dry up during certain periods, leaving less water available for plantlife, animals, and people and making the environment more arid. So climate plays a defining role in the caatinga, shaping the landscape and the habits of those who dwell in this biome.

Images

* Photo: Marcos..Fernandes/Flickr

**Photo: Marcos Pereira/Wikipedia

***Photo: Brian Gratwicke/Wikipedia

****Photo: Karinna Paz/Flickr

*****Photo: Glauco Umbelino/Wikipedia

Learn more about other biomes and ecosystems:

The Amazon biome

The Pantanal biome

The Atlantic Rainforest biome

Cerrado Biome

Southern Plains Biome

The Coastal Biome

Sources:

Ibama
Biosfera da caatinga

Linhares, Sérgio & Gewandszbajder, Fernando. Biologia Hoje - Vol 3. São Paulo: ed. Ática, 1998.

Consultancy: Vânia Rocha, bióloga / Museu da Vida (Fiocruz).

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