Bahia forests

Category: Forest Biomes.

Geographic Location: South America.

Summary: The Bahia forests, located on the southeastern coast of Brazil, are home to several critically endangered species threatened by agricultural and other land-clearing activities.

The Bahia forests are composed of three main sections: coastal, interior, and southern moist forests. The average annual rainfall is 39 to 71 inches (1,000 to 1,800 millimeters), with a temperature range of 62 to 83 degrees F (17 to 28 degrees C). The Bahia coastal forest covers approximately 38,610 square miles (100,000 square kilometers) and occupies a strip 93 miles (150 kilometers) wide bordering the Atlantic Ocean.

This coastal forest is home to a large number of endemic (evolved in and uniquely native to a specific biome) plants, birds, primates, and butterflies that have become critically endangered, including the golden-headed lion tamarin (Leontopithecus chrysomelas). The types of vegetation that can be found in the coastal forest are Atlantic moist (evolved to thrive in high-rainfall zones) and semi-deciduous (losing leaves only in the short dry season), often in a setting with up to four strata topped by a 100-foot-high (30-meter-high) canopy.

Researchers have found that almost 30 percent of the vascular plants in these coastal forests are endemic. This segment of the Bahia Forests biome represents a range limit for many Amazonian species of plants and birds. In other words, many such species have a particular habitat niche, food source, or temperature requirement that can be found here, but not north of this region. Diversity in the Bahia forests approaches the level of diversity in the Amazon rainforests, but the species profile is distinctly regional.

Interior Forests

Interior forests occupy 41 percent of the total land area in Bahia and constitute 75 percent of Bahia forests. This area of 88,803 square miles (230,000 square kilometers) contains both semi-deciduous and seasonal deciduous areas, and is home to several critically endangered endemic species. The Coimbra titi monkey (Callicebus coimbrae), for example, was recently found to be an endemic species in danger of extinction. Although the interior is considered to be a species-rich area, the exact amount of biodiversity therein is unknown. In 1993, biologists discovered the presence of two highly specialized endemic birds: the slender antbird (Rhophornis ardesiaca) and the narrow-billed antbird (Formicivora iheringi).

Interior forests are among the most modified and fragmented ecoregions of the Bahia forests. Due to activities such as logging and cocoa plantations, few continuous stretches of interior forest cover more than four square miles (10 square kilometers). Less than 1 percent of the interior forests are protected. The most common method of protection has been the creation of parks, with the most representative park of the ecoregion being the State Park of Rio Doce, comprising about 139 square miles (359 square kilometers) in the middle of the valley of Rio Doce, just south of the city of Ipatinga. This park, small in comparison to the vast forest resources of the area, does not provide adequate protection for these habitats. Though the Brazilian Forestry Code was passed in 1965, with the aim of protecting 247 million acres (100 million hectares), lack of proper enforcement has resulted in approximately 40 percent of the area being deforested.

Southern Moist Forest

The moist forest of southern Bahia extends southward from the Salvador to northern Espirito Santo state. It is approximately 62 to 124 miles (100 to 200 kilometers) inland from the coast, originally covering 27,220 square miles (70,500 square kilometers), manifesting as a half wet and half mesophytic (midrange of moisture) forest. Trees in the region flower throughout the year but usually experience a distinct peak from October to December.

The moist southern forests have epiphytes (plants perched upon other plants) on up to 80 percent of the trees. As many as 40 percent support lianas (large, rooted woody vines). Several important plant families are present in terms of diversity, density, and dominance, including myrtle (Myrtaceae), the evergreen Ericales shrubs and trees (Sapotaceae), Poincianas and other Fabaceae (Caesalpiniaceae), laurels (Lauraceae), and coco plums and related woody evergreens (Chrysobalanaceae).

Effects of Human Activity

Human activities have reduced the forests by more than 35 percent, to a current area of less than 9,527 square miles (24,675 square kilometers). Approximately 494,211 acres (200,000 hectares) are used for pastures, cocoa plantations, and rubber plantations. Attempts are being made to reduce these activities, however, as approximately 98,842 acres (40,000 hectares) of this forest are in the initial stages of regeneration. Despite the Forestry Code of 1965, less than 0.1 percent of wet forests and none of the mesophytic forests are protected.

The Una Biological Reserve is one of the most important forest sanctuaries, preserving one of the largest areas of contiguous forests—as much as 49 percent of the mature forests. Many of the mature forest areas in Una, however, are directly exposed to human activities. Further, most forest reserves are inadequately staffed or patrolled, allowing continued fragmentation and degradation of the habitat.

Approximately 1,931 square miles (5,000 square kilometers) of Atlantic coastal forest is already subject to cocoa planting and cattle ranching, which have increased habitat loss and forest fragmentation, endangering many of the valuable endemic species of the region. Less than 5 percent of the original coastal forest remains, which has caused conservationists to place it at the top of the priority list for biodiversity protection. One measure has been to create biological and forest reserves, such as the Sooretama Biological Reserve and Linhares Forest Reserve, to protect the forests from any potential anthropogenic threat to the habitat and the native species.

The demand for access to land in Bahia threatens all forest resources. The creation of forest reserves and state parks are to date inadequate measures to provide protection for these vast resources. Given limited government intervention and enforcement of the 1965 Forestry Code, there is a need for creative means of protection, such as providing greater enforcement and management autonomy to indigenous populations and enforcing stringent laws that value the ecological resource. Though there is nongovernmental organization work on deforestation, such groups often face opposition from government, which believes that deforestation is necessary for national development.

Global warming presents additional pressures, as rising temperature patterns and altered precipitation regimes can lead to more severe fire damage, erosion threats, and species dislocation through habitat degradation and fragmentation—and through these effects, the loss of a valuable carbon sink that can help mitigate greenhouse gas buildup. But these forests can only perform that ecological service to the extent that they are protected and sustained.

Bibliography

Mori, Scott A., Brian M. Boom, Andre M. de Carvalho, and Talmon S. dos Santos. “Southern Bahian Moist Forests.” Botanical Review 49, no. 2 (1983).

Paciencia, Mateus L., and Jefferson Prado. “Effects of Forest Fragmentation on Pteridophyte Diversity in a Tropical Rain Forest in Brazil.” Vegetation 180, no. 1 (2005).

Souza-Alves, Joao P. et.al. "Food Availability, Plant Diversity, and Vegetation Structure Drive Behavioral and Ecological Variation in Endangered Coimbra Filho's Titi Monkey." American Journal of Primatology, 1 Mar. 2021, publons.com/wos-op/publon/10.1002/ajp.23237/. Accessed 20 July 2022.

Voeks, R. A. “Tropical Forest Healers and Habitat Preference.” Economic Botany 50, no. 4 (1996).