JOSÉ SABINO / NATURE IN FOCUSA natural amphitheater: floodplains, surrounded by a plateau regionJOSÉ SABINO / NATURE IN FOCUS
“Imagine a huge amphitheater in the heart of South America,” said José Sabino, a biologist and lecturer when referring to the geographic mosaic forming the Pantanal wetland, in the Midwest region of Brazil. With 140 square kilometers (km2) and a dynamic of alternating annual cycles of drought and flooding that influence ecological interactions and patterns of biodiversity, the Pantanal is the largest wetland in the world. It is surrounded by mountains that can reach a height of 1,400 meters, “which enliven the landscape, but are also connected to the main threats to biodiversity in the region,” said Sabino. Sabino is a researcher at the Universidade Anhanguera-Uniderp and was a guest speaker for the BIOTA-FAPESP Education Conference Cycle, held in São Paulo on April 18. Walfrido Tomas, a veterinarian with the Wildlife Laboratory of the Brazilian Agricultural Research Corporation (Embrapa-Pantanal), and Arnildo Pott, an agronomist at the Federal University of Mato Grosso do Sul (UFMS) also spoke.
The occupation and haphazard use of land for agriculture and livestock in the regions adjacent to the wetland, often stimulated by public policies, are now a major threat to preserving local biodiversity, the speakers pointed out. “The unsustainable use of land on the plateaus has caused soil erosion and, as a direct consequence, the silting of rivers,” said Sabino, who indicated that the most emblematic case has occurred in the Taquari river basin. “Since the 1970s, the intensification of agriculture without proper soil conservation has culminated in the almost complete silting of the lower course of the river.” This has resulted in the breaking of its banks and the permanent flooding of more than 5,000 km2 of an area where flooding used to be seasonal (see Pesquisa FAPESP No. 116). “This has made the economic activities typical of the region impossible, reduced fisheries production and has substantially altered the composition of local flora and fauna,” he said. According to Sabino, Pantanal livestock development, traditionally based on the use of native pastures, was always considered to be of low impact to its biodiversity. But the trend in recent years towards intensified production has led cattle ranchers and farmers to cultivate exotic pastures, which causes deforestation of native forests.
Other activities also threaten the biome. For example, manufacturing, mining, and energy production by hydroelectric power plants have the potential to alter the natural dynamics of the ecosystems that make up the Pantanal. “Power plants can impair the flow of nutrients transported by water and the hydrological functioning that feeds the Pantanal wetland, in addition to altering the habitat of aquatic and semiaquatic species and the ecosystem services that these species perform in the region,” said Tomas.
Still, the Brazilian Electricity Regulatory Agency (Aneel) has called for bids to construct small hydropower plants in the watershed of the Upper Paraguay, warned Sabino. “The construction of these plants may compromise the migration of certain fish species in the region,” he said. Mining already imposes the risk of environmental pollution. “The mining of manganese and iron, for example, can lead to the loss of vegetation characteristic of the Pantanal, affecting a number of species and impairing the availability of water resources essential to the maintenance of local biodiversity,” said Sabino. Gold mining in the northern Pantanal has already polluted large areas with mercury, he said.
Fotos: Eduardo CesarFrom left to right: Walfrido Tomas, Arnildo Pott and José SabinoFotos: Eduardo Cesar
Thus, because it is a natural area shaped by the availability of water, particularly the Paraguay River and an extensive network of tributaries whose headwaters are in the adjacent plateaus, the successful implementation of conservation strategies must include a change in Pantanal management for the Upper Paraguay watershed, concluded Tomas. “Public conservation policies need to include the biome and the headwaters of the rivers that feed it.” In his opinion, compensation strategies, exemption and certification of best management practices for landowners who conserve the diversity of the Pantanal landscapes should also be encouraged. “The cultivation of pastures to increase production has become a constant in the Pantanal. We must invest in rewarding cattle farmers and ranchers who do not intensify their production through this type of planting. After all, the cattleman who tends his livestock without altering the landscape is contributing to the conservation of the biome,” he said.
About 5% of the Pantanal is protected by conservation areas. Although this approach is well accepted by public officials, in practice it is inefficient when it comes to wildlife preservation. “Conservation of the most critical species depends more on sustainable management of farms/ranches than on the existing conservation units,” said Tomas. He was referring to species such as the jaguar, giant otter and hyacinth macaw, found more frequently beyond the boundaries of conservation units. “The species are not evenly distributed across the Pantanal. Therefore, the preservation of these animals requires broader strategies than the simple management of these conservation units.”
Territorial crossroads
The Pantanal today occupies 1.8% of Brazil’s national territory. It is the smallest of the six Brazilian biomes — the largest being Amazonia, which spans 50% of Brazil’s total area. But the Pantanal’s smaller size does not necessarily reflect its biological complexity. Geographically, it is located at a territorial crossroads. It encompasses part of southern Mato Grosso State and a section of northwestern Mato Grosso do Sul State, and extends to eastern Bolivia and northern Paraguay. “It’s the end of the world! Or the beginning of it, depending on your point of view,” joked Arnildo Pott. In his view, this advantageous location allows it to interact with several ecosystems such as Amazonia and the Cerrado, in addition to enclaves of the Atlantic Forest. “Pantanal flora is strongly influenced by the phytogeography of these biomes. In some regions we can find aquatic vegetation within one meter of vegetation characteristic of the Caatinga,” he said. Some plant species that are widely distributed among the fields of the Pampa, such as Macrosiphonia velame, and Brasiliopuntia brasiliensis in the Caatinga, can easily be identified in the Pantanal.
This is also true of Pantanal fauna. According to Tomas, most Pantanal mammals are typical of the Cerrado, while most bird species come from Amazonia and the Atlantic Forest. “It is also possible to find populations of Amazonian fish there,” he said. Characterized mainly as a steppe savannah, the Pantanal is a humid area with the greatest variety of bird species in the world. “It helps that the biome is located on a migratory route,” he said. But there are gaps to be filled when it comes to geographic and taxonomic knowledge of the region’s biological diversity. Such is the case of lesser known groups such as crustaceans, mollusks and butterflies. “The Mato Grosso do Sul Biota program, which is in the process of implementation, will help us to better understand the complexity of Pantanal biological diversity,” he said.
There are few records of endemic species of the biome. According to Tomas, what distinguishes the Pantanal is not the endemism of species, but the abundance of populations. “We estimate that there are 45,000 marsh deer (Blastocerus dichotomus), over 3 million caimans (Caiman yacare), 5,000 hyacinth macaws (Anodorhynchus hyacinthinus) and from 3,000 to 5,000 jaguars (Panthera onca). However, these numbers may vary according to the seasonal fluctuations that dictate the periods of Pantanal droughts and floods,” he said. In any event, the lack of endemism in the Pantanal is offset by the interactions among the species living there and their biological processes that are unique to the region. “These processes are endemic and need to be preserved, as they have important ecosystem functions for maintaining the biological diversity of the Pantanal,” said Tomas.
JOSÉ SABINO / NATURE IN FOCUS… Hyacinth macaw…JOSÉ SABINO / NATURE IN FOCUS
Sustainable managementAccording to Sabino, mitigating threats to Pantanal biodiversity also depends on governance. “We need to make the connection between the knowledge we produce on Pantanal biological biodiversity and how this knowledge can be useful to society,” he said. In his view, we need to stress how important the biodiversity of this biome is to Brazil, by showing how to create the conditions for building a more harmonious relationship with nature. There are some initiatives in this direction, said Sabino. “The Biota-FAPESP program is an example of this,” he said.
Public policies aimed at organizing ecotourism in the region should be introduced within the context of management and governance, the speakers stressed. “The Pantanal has enormous potential for ecotourism, but, alas, this activity is still being done in an amateurish fashion,” said Tomas. Costa Rica alone, said Sabino, receives three times more tourists than Brazil. “Brazil has yet to exploit this activity. We need to recognize our potential to properly encourage its usefulness.”
This potential is vast in the Pantanal. One of the attractions is clear water, such as that of the Olho d’Água river, “as clean as or cleaner than that of the Fernando de Noronha archipelago off the northeast coast of Brazil and the Caribbean,” said Sabino. In large part this is due to conservation of the forests along the banks of the rivers. This preservation not only guarantees the purity of the water but also the integrity of ecological processes, such as the complicit relationship between tufted capuchins and piraputanga fish (Brycon hilarii), a species of silvery fish of the family Characidae.
JOSÉ SABINO / NATURE IN FOCUS… and Marsh alligator: found more often outside of conservation unitsJOSÉ SABINO / NATURE IN FOCUS
According to Sabino, piraputanga fish have a fantastic capacity for acoustic and visual guidance, so that any noise coming from the surface of the water attracts their attention. Capuchins are proficient at scattering seeds when they feed, what researchers call destructive foraging. “For every one or two fruits they put in their mouths, they drop several others,” he said. When they fall into the water, these fruits end up attracting the attention of the piraputanga, redirecting them to where these seeds are released. These fish then start to follow the monkeys since they indirectly feed the piraputanga. “This is just one of the tourist potentials of the Pantanal,” he concluded.
The BIOTA-FAPESP Education Conference Cycle is an initiative coordinated by the Biota-FAPESP program and Pesquisa FAPESP. Its objective is to contribute to improving the quality of science and environmental education in Brazil. Between now and November there will be six lectures (see schedule at right), which will address the challenges and threats to the six major Brazilian biomes: Cerrado, Caatinga, Atlantic Forest, Amazonia, in addition to the marine and coastal environments and biodiversity in anthropic environments, urban and rural.
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