The Atlantic Forest is a unique and significant South American biome, often referred to as Mata Atlântica in Portuguese. Once spanning an immense area of over 1.2 million square kilometers, it stretched along Brazil’s Atlantic coast and extended inland. Today, this forest exists as a severely fragmented landscape, with human activity destroying approximately 88% of its original vegetation. Despite its diminished state, the Atlantic Forest remains globally important due to its biological richness and the ecosystem services it provides.
Geographic Extent and Characteristics
The Atlantic Forest biome primarily covers Brazil’s eastern coastline, from Rio Grande do Norte to Rio Grande do Sul. Beyond Brazil, its reach extends inland into eastern Paraguay and northeastern Argentina, particularly in Misiones Province. Historically, it was the second largest rainforest on the planet, trailing only the Amazon rainforest in size.
This biome encompasses a variety of topographies, from coastal lowlands to rugged mountains and plateaus, with elevations reaching up to 2,000 meters. The climate zones within the Atlantic Forest range from tropical to subtropical, influencing the distinct forest types. These include evergreen tropical moist forests, semi-deciduous forests (where trees shed leaves in the dry season), and Atlantic dry forests that transition to drier biomes. Coastal areas feature restinga (low forests on dunes) and mangrove forests along the shoreline.
Unparalleled Biodiversity
The Atlantic Forest is renowned for its extraordinary species richness and high levels of endemism, meaning many species exist nowhere else on Earth. Despite its fragmentation, it still ranks among the world’s top biodiversity hotspots, harboring one in 14 of Earth’s plant species and one in 20 of its vertebrate species. Approximately 40% of its vascular plants and up to 60% of its vertebrates are endemic.
Specific examples of this unique biodiversity include a vast array of life forms. Over 20,000 plant species have been identified, with some areas exhibiting as many as 450 tree species in a single hectare. The forest is home to more than 2,000 vertebrate species, including 298 mammal species (90 endemic). Among mammals, it hosts 26 primate species, with 21 found exclusively here, such as the golden lion tamarin and woolly spider monkey.
Bird diversity is also remarkable, with 1,023 species (nearly 200 endemic), including the red-tailed parrot. Amphibians are particularly unique, with 475 species, 286 of them endemic, while 306 reptile species include 94 endemics. This biodiversity is attributed to the forest’s evolutionary isolation from the Amazon and its diverse microclimates, fostering distinct species over millions of years.
Ecological Significance
Beyond its remarkable biodiversity, the Atlantic Forest provides many ecosystem services. It plays a significant role in regulating water for major urban centers, including São Paulo and Rio de Janeiro, which house a large portion of Brazil’s population. The forest acts as a natural filter, ensuring the supply of clean drinking water to approximately 150 million people.
The forest also protects against soil erosion, particularly on steep slopes and coastal areas, by stabilizing the ground with its extensive root systems. This function helps prevent landslides and maintains soil fertility, which is beneficial for surrounding agricultural lands. Furthermore, the Atlantic Forest contributes to climate regulation through carbon sequestration, absorbing atmospheric carbon dioxide. One hectare of forest in the Serra do Mar ecoregion can store an estimated 320 to 460 tons of carbon, depending on elevation. The forest supports local communities by providing natural resources, including timber and non-timber forest products, and contributes to the livelihoods of many people.
Pressures and Degradation
The Atlantic Forest has endured extensive pressures for centuries, leading to its severe fragmentation and degradation. Its decline began with European colonization in the 16th century, driven by logging and sugar cane plantations. This led to continuous deforestation, transforming a vast forest into isolated remnants.
Today, the primary causes of its degradation include continued agricultural expansion, particularly for cattle ranching and soy cultivation. Urbanization and infrastructure development, fueled by the concentration of 70% of Brazil’s population and GDP within the biome, further contribute to habitat loss. Illegal logging persists as a threat, targeting valuable timber species and exacerbating forest fragmentation. Additionally, climate change impacts, such as altered rainfall patterns and increased temperatures, pose emerging challenges to the forest’s long-term health and resilience. Remaining forest tracts are highly fragmented, with 97% of fragments smaller than 50 hectares, making them more vulnerable to edge effects and species loss.
Conservation and Restoration Initiatives
Various efforts are underway to protect and restore the remaining fragments of the Atlantic Forest. A significant approach involves the establishment of protected areas, such as national parks and biological reserves. Examples include the Atlantic Forest South-East Reserves in Brazil, a UNESCO World Heritage Site with 25 protected areas covering 470,000 hectares. In Paraguay, Mbaracayu National Park and San Rafael Lagoon National Park are UNESCO Biosphere Reserves, safeguarding blocks of the Upper Paraná Atlantic Forest.
Large-scale reforestation and ecological restoration projects are also being implemented to reconnect fragmented areas and increase forest cover. These involve planting native species and promoting natural regeneration to restore ecological processes. Non-governmental organizations (NGOs) and scientific research institutions play a significant role by conducting biodiversity surveys, developing conservation strategies, and raising awareness. Community involvement engages local populations in sustainable practices that balance economic needs with forest conservation, such as sustainable agriculture and ecotourism.