{"id":159945,"date":"2014-02-09T16:21:45","date_gmt":"2014-02-09T18:21:45","guid":{"rendered":"http:\/\/revistapesquisa.fapesp.br\/?p=159945"},"modified":"2015-01-09T17:18:04","modified_gmt":"2015-01-09T19:18:04","slug":"the-many-faces-of-the-sertao-2","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/the-many-faces-of-the-sertao-2\/","title":{"rendered":"The many faces of the sert\u00e3o"},"content":{"rendered":"

Published in July 2013<\/em><\/p>\n

\"Fazenda

FERNANDO ROSA<\/span>Fazenda Dona Soledade, in the Brazilian state of Para\u00edba: environmental diversity is a distinguishing feature of the CaatingaFERNANDO ROSA<\/span><\/p><\/div>\n

During an 1818 Austrian expedition to Brazil \u2013 a scientific investigation that brought over researchers and artists to study and depict species and landscapes characteristic of Brazilian biodiversity \u2013 two naturalists, Carl Friedrich von Martius and Johann Baptiste von Spix, were struck by the diversity of vegetation in a forest that was theoretically rare for the region around the banks of the S\u00e3o Francisco River, in what is now the municipality of Janu\u00e1ria, Minas Gerais State. Their fascination largely arose from the fact that the vegetation was in an area that was part of the Caatinga, an ecosystem identified by a predominantly semi-arid climate and scarce, highly variable water availability. Like many others, the two German naturalists probably thought that the Caatinga was a homogeneous environment, but that is not the case. \u201cThe region has a wide variety of environmental conditions that are essential to the emergence and sustenance of a number of species well adapted to the regional climate,\u201d said biologist Br\u00e1ulio Almeida Santos of the Federal University of Para\u00edba (UFPB), in a lecture he presented at the fifth BIOTA-FAPESP Education Conference Cycle, on June 20, 2013 in S\u00e3o Paulo.<\/p>\n

The Caatinga, he explained, presently occupies 11% of Brazilian territory, an area approximately 845,000 square kilometers (km2<\/sup>) in size. It is divided into eight ecoregions \u2013 each having very distinct landscapes, soil types and vegetation \u2013 that can receive rainfall of less than 1,000 millimeters over a year. \u201cIn some areas, a dry spell can last as long as 11 months,\u201d he said. The region is currently experiencing its worst drought in 30 years, affecting the lives of 27 million people. In the state of Bahia alone, over 214 municipalities have declared a state of emergency this year.<\/p>\n

\"Left

L\u00c9O RAMOS<\/span>Left to right, biologists Br\u00e1ulio Almeida Santos, Luciano Paganucci de Queiroz and Adrian GardaL\u00c9O RAMOS<\/span><\/p><\/div>\n

During the course of thousands of years, these environmental factors have elicited specific adaptive responses from the local plants, enabling them to survive in an increasingly hot and dry environment. One response in certain species involves an adjustment in leaf retention \u2013 and for good reason: the fewer leaves on a plant, the less water it loses during the driest seasons. Some of these plants are able to fix carbon dioxide (CO2<\/sub>) at night and use it for photosynthesis during the day when their stomata-structures in the leaves that enable water and gas exchange \u2013 are closed. \u201cThese are just some of the mechanisms these species have found for preventing water loss via transpiration through the leaves. [This is] a simple strategy, but it enables them to retain water for the driest periods,\u201d said biologist Luciano Paganucci de Queiroz of the Federal University of Feira de Santana in Bahia, a guest speaker for the conference cycle.<\/p>\n

According to Queiroz, this type of rationing is a determining factor in the size of these plants and their leaves because this mechanism not only enables them to better adapt to the semi-arid climate but also limits the emergence of large trees. \u201cThe plants in the Caatinga do not grow continuously because sufficient water is not available to them throughout the entire year,\u201d the biologist noted.<\/p>\n

\"a

ADRIAN GARDA<\/span>The tree\u00a0frog (Corythomantis greeningi<\/em>): complex\u00a0adaptations to climate adversitiesADRIAN GARDA<\/span><\/p><\/div>\n

Another adaptive response of these plant species to the varied semi-arid environments is the protection they have developed for their leaves. Protection is afforded by means of thorny or pointy protrusions on the surface of the plant stem and trichomes, small \u201chairs\u201d containing itchy or stinging substances that can cause allergic reactions upon contact with skin. Many plants in the Caatinga, such as cactus, are armed with these natural shields. \u201cIt is a very interesting defense mechanism against herbivorous animals,\u201d Queiroz commented. \u201cThese species retain their leaves for only a short time during the year, and consequently they are very precious and need to be protected.\u201d The conditions to which these plant species have been subjected, he says, are becoming an important environmental filter, influencing the evolutionary process of the species in this ecosystem over time.<\/p>\n

\"030-033_Biota_209\"<\/a>Abundance of species
\n<\/strong>Despite these unfavorable circumstances, the Caatinga has an enormous variety of plants \u2013 about 6,000 species, including 1,333 genera, of which 18 are native (endemic) to the region. Of the 87 species of cactus in the Caatinga, 83% are exclusive to this ecosystem. Examples include mandacaru (Cereus jamacaru<\/em>) and xique-xique (Pilosocereus gounellei<\/em>), species that are threatened primarily \u201cbecause they are removed from their environment when they are still small and sold as souvenirs at road-side restaurants,\u201d Queiroz warned.<\/p>\n

Leguminosae<\/em>, the most diverse plant family in the Caatinga, includes several species exclusive to the semi-arid region, such as mucun\u00e3 (Dioclea grandiflora<\/em>) and jurema-preta (Mimosa tenuiflora<\/em>). Many of these plants perform important ecological functions. Owing to their association with some types of bacteria, these plants help fix nitrogen in the soil, thereby raising the available nutrient levels. However, even with the progress achieved in identifying new species such as Prosopanche caatingicola<\/em>, a parasitic plant catalogued in 2012, data on the floristic biodiversity of this ecosystem is still very limited.<\/p>\n

This knowledge gap also extends to the fauna of the Caatinga, particularly the invertebrates. The point was emphasized by biologist Adrian Garda of the Federal University of Rio Grande do Norte (UFRN), one of the June 2013 conference speakers. According to Garda, it was long held that the Caatinga was an ecosystem devoid of character, with low rates of endemism and species diversity. \u201cIt was thought that the Caatinga was a subsample of other ecosystems,\u201d he said. Today, we know that it is the world\u2019s most diverse semi-arid region.<\/p>\n

Threat to diversity
\n<\/strong>According to data from the Ministry of the Environment (MMA), the semi-arid region of Caatinga has 591 bird, 241 fish and 178 mammalian species. According to estimates, 41% of species in the Caatinga are still unknown, and 80% have been insufficiently studied. \u201cThere is a shortage of data on animal diversity in this ecosystem,\u201d Garda noted. However, the rates of endemism recorded there suggest that the fauna have gone through an independent local evolutionary process, with many species adapted to the region.<\/p>\n

For example, Corythomantis greeningi<\/em>, a tree frog typical of the region, spends months during the drought periods hibernating in small rocky niches shielded by its highly modified skull, protecting itself from predators and storing water. Scriptosaura catimbau<\/em>, a lizard adapted to regions with sandy soils, \u201cliterally buries itself and \u2018swims\u2019 beneath the sand,\u201d he commented. Other species, such as Pleurodema diplolister<\/em>, a type of frog, can bury themselves over 1.5 meters deep to look for water during drought periods. \u201cBut we still need a better understanding of what we are trying to preserve,\u201d Garda concluded.<\/p>\n

\"a

ADRIAN GARDA<\/span>The snake of the species Epicrates assisi…<\/em>ADRIAN GARDA<\/span><\/p><\/div>\n

According to the MMA\u2019s Department of Biodiversity and Forests, 15,000 km\u00b2 were deforested in the semi-arid region between 2002 and 2008, amounting to a little more than 2,000 km\u00b2 per year. Today, just 54% of the original vegetation in the Caatinga remains. According to Santos, of the 364 conservation units registered with the MMA, 113 are designated for ecosystem protection and preservation, but these account for only 7.5% of the Caatinga\u2019s total area of 845,000 km\u00b2.<\/p>\n

Santos believes that the principal cause of deforestation in the Caatinga region is energy production. When cut down, a native forest yields wood and charcoal for steel plants in the states of Minas Gerais and Esp\u00edrito Santo or for the gypsum and ceramics industries operating within the semi-arid region. In his assessment, the consequences of misuse of the region\u2019s natural resources are loss of habitat and fragmentation of ecosystems. \u201cIt is not a question of ceasing to use the Caatinga\u2019s natural resources but rather of identifying to what extent we can use them without compromising the region.\u201d<\/p>\n

Santos noted that the unregulated raising of goats and sheep has also contributed to degradation of the vegetation in the Caatinga. Approximately 17 million goats and sheep consume the local vegetation each day. \u201cOften the fencing needed to keep the herd confined within an area costs more than the land. As a result, many farmers let their animals run free, and they consume vegetation indiscriminately.\u201d He believes that unplanned use of natural resources is already leading to desertification in the Caatinga.<\/p>\n

\"...common

FERNANDO ROSA<\/span>…common in regions such as Cabaceiras, in Para\u00edba StateFERNANDO ROSA<\/span><\/p><\/div>\n

\u201cThe remaining vegetation needs to be preserved by expanding the network of protected areas,\u201d Santos said. \u201cIt is important to promote proper management of areas influenced by human activity, and to educate everyone who lives among the region\u2019s natural resources or uses them, to promote the idea that these resources belong to the Caatinga.\u201d To achieve that goal, he concluded, it is critical that we expand support for research and education as well as oversight, so that we can preserve the biological diversity of the Caatinga that German naturalists discovered long ago. \u201cWe imagine ourselves transported to an entirely different country. Instead of dry, defoliated forests or high, open wilderness, we find ourselves surrounded on all sides by verdant forests that border extensive lakes abundant with fish,\u201d they wrote in the narrative Reise in Brasilien (Travels in Brazil) in which they recount their 1817-1820 excursions there.<\/p>\n

The BIOTA-FAPESP Education Conference Cycle is an initiative of the BIOTA-FAPESP program in partnership with Pesquisa FAPESP, focused on discussing the challenges involved in preserving Brazil\u2019s principal ecosystems, Pampa, Pantanal, Cerrado, Caatinga, Atlantic Forest and Amazonia, in addition to the marine and coastal environments and biodiversity in anthropic environments, urban and rural. The lectures are intended to present knowledge gathered by researchers throughout Brazil and are aimed at improving the quality of environmental and science education for high school teachers and students in Brazill.<\/p>\n","protected":false},"excerpt":{"rendered":"Semi-arid climate have elicited adaptive responses among species","protected":false},"author":346,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[159],"tags":[206,200,262],"coauthors":[662],"class_list":["post-159945","post","type-post","status-publish","format-standard","hentry","category-science","tag-biodiversity","tag-environment","tag-sustainability"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/159945","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/users\/346"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=159945"}],"version-history":[{"count":0,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/159945\/revisions"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=159945"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=159945"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=159945"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=159945"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}