Only 7.5% of the Caatinga is protected

The Northeast’s semiarid biome is the most susceptible to human interference and climate change, warn researchers.

By Karina Toledo

Agência FAPESP – The Caatinga is considered by specialists of the Brazilian biomes to be the most susceptible to human interference and global climate change. Despite this fact, only 7.5% of the biome is protected in Conservation Units (CUs), and a mere 1.4% of these reservations are in full protection areas. This warning was stated by Bráulio Almeida Santos, a biologist at Universidade Federal da Paraíba’s Center of Exact Sciences and Nature (CCEN/UFPB), during the fifth meeting in the BIOTA Education’s 2013 Conference Cycle, which was organized by the BIOTA-FAPESP Program on June 20.

“The Northeast Region has 364 registered reservations in the National Register of Conservation Units (CNUCs). Although this biome is predominant throughout the Brazilian semiarid region only 113 UCs (or 31%) aim to protect the Caatinga. It is a contradiction that must be corrected,” said Santos.

According to a study conducted by the biologist, almost half of the 113 UCs are private, and only 9% have management plans. In Santos’ evaluation, the situation reflects the erroneous idea that was disseminated for long time that the Caatinga is a poor, homogenous biome that had “almost nothing to be preserved.”

“The Caatinga was always the ugly duckling of Brazilian biomes. The top priorities are Amazonia, the Atlantic Rainforest and the Cerrado [savannah areas]. The image of the Caatinga is of a scorching sun and cattle dying of thirst, but it is the semiarid region with the greatest biodiversity in the world,” affirmed Santos.

Regardless, the species found in the Caatinga are still not well described. Indeed, roughly 41% of the biome has never been sampled. According to data from the Environment Ministry, 932 species of region’s plants, 241 fish, 79 amphibians, 177 reptiles, 591 birds, 178 mammals and 221 bees have been described to date. In the case of flora, more than 30% of the species described are endemic, meaning they are not found in any other region in the world.

The rates of endemism reach 57% in the case of fish, 37% in the case of lizards, 12% among amphibians and 7% among birds, according to data presented by Adrian Antonio Garda of the Universidade Federal do Rio Grande do Norte’s Biosciences Center (CB-UFRN).

“The number of species described may appear small when compared to other Brazilian biomes. But we are comparing it to the country’s biomes that have greater diversity and completely different climatic conditions. When compared to better-studied desert regions, the Caatinga has more than double the number of species, with high levels of endemism, despite the fact that more than 40% of the biome has never been inventoried,” said Garda.

In Santos’ evaluation, there is a lack of critical mass within the universities and local research institutes to broaden the knowledge on the subject and to disseminate it among formulators of public policy. “Information must reach public managers. The lack of political will and leadership that is committed to the rational use of the Caatinga is one the obstacles to the conservation of this biome,” he commented. The myth that the Caatinga has not been altered very much must also be debunked, asserted Santos, as it is estimated that only 54% of the biome remains. The states that lead in deforestation of the Caatinga are Bahia, Ceará, Piauí and Pernambuco.

“However, unlike what has occurred in the Atlantic Rainforest, we do not know precisely what the biome has lost and how the remaining fragments are distributed. From a conservation standpoint, it is fundamental to ascertain whether there are many small fragments or a few large fragments to consider reconnecting the landscapes,” Santos said.

Reversing the loss of habitat in the Caatinga, however, is not a simple task, explained Santos. The scarcity of water in the region makes photosynthesis difficult and makes the biome have a very limited resilience to human interference.

Threats

According to Santos, the main factor contributing to the current degradation of the Caatinga is deforestation practices to obtain firewood and charcoal. Roughly one third of the timber cut is for residential use, whereas the greater part of the charcoal will be used for the centers of steel, plaster and ceramic industries in the Northeast.

The biologist also cited threats, such as the indiscriminate use of fire in agriculture and livestock practices, the introduction of exotic fruit to the region and the extensive raising of livestock (caprine, ovine and bovine). “I am not advocating that the people stop raising goats or using firewood; this is part of the local economy and culture. However, the use of resources must be ordered to guarantee rational use; if not, the result will be desertification,” cautioned Santos.

Another important threat, as contradictory as it may seem, is the excessive use of water for agricultural irrigation. “In the Caatinga, it naturally rains very little, and the soil is compact and hard. Instead of being rapidly absorbed and conducted to the ground water, water accumulates and brings the existing salts and nutrients in the soil to the surface. Thus, when the water evaporates, salinization of the soil occurs and compromises vegetation and agriculture,” explained Santos.

According to the researchers, desertification centers – areas with high degrees of environmental degradation where the soil is exposed and exhibits a high degree of erosion, there is little biological diversity and scarce vegetable coverage –already exist.

“The region at the greatest risk of desertification in Brazil is in the Northeast. Because it is naturally a semi-arid region, the Caatinga is the biome that is most threatened by climate change. As the planet warms, the already large water deficit will tend to increase,” Santos warned.

In addition, during the fifth meeting in BIOTA Education’s 2013 Conference Cycle, Luciano Paganucci of the Universidade Estadual de Feira de Santana’s Biological Sciences Department (DCBio/UEFS) presented a panorama of the Caatinga’s flora, speaking about its origin and evolution and the adaptive responses developed to address the lack of water.

Organized by a BIOTA-FAPESP program, the 2013 Conference Cycle aims to contribute to improvements in science teaching. The next meeting will be on August 22, 2013, when the subject will be the “Amazonia Biome.”
In October 24, the topic will be “Marine and Coastal Environments.” Completing the cycle, the topic in November will be “Biodiversity in Anthropic Environments – Urban and Rural.”