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Revta. brasil. Bot. 4: 149-153 (1981) The caatingas dominium DÁRDANO DE ANDRADE-LIMA Universidade Federal Rural de Pernambuco (UFRPE), Empresa Pernambucana de Pesquisa Agropecuária (IPA), Caixa Postal 1022, 50000 Recife, Pernambuco, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). ABSTRACT — (The caatingas dominium). A critical review of the current state of knowledge of the caatinga vegetation of northeastem Brazil is presented, with observations on the geographical, geological-soil and climatic factors together with Man-made disturbance which have influenced the various facies of this vegetation. A new classification is presented, based essentially on physiognomic and floristic criteria, which delimits five vegetation units and twelve community types which can be currently recognized in the caatinga. RESUMO -— (O domínio das caatingas). Uma revisão crítica do estado atual do conhecimento sobre a vegetação da caatinga no Nordeste do Brasil é apresentada, com observações sobre os fatores geográficos, geológicos (solo) e climá- ticos, bem como as perturbações causadas pelo Homem que tem influenciado as várias fácies desta vegetação. Uma nova classificação é apresentada, baseada essencialmente em critérios fisionômicos e florísticos, que delimitam cinco unidades de vegetação e doze tipos de comunidades que podem ser reconhecidas atualmente na caatinga Key words: caatinga, classification. Introduction The vegetation of the drier part of northeas- tem Brazil, in Koeppen's BSH climatic type, was called caatinga by the Indians of that region, and the name has been maintained both in common use and scientific literature. The term means “open forest” or “open vegetation”. We do not know whether the whole area was once entirely covered by such “open forest” and has become through human influence the present landscape with wide stretches of low or almost nonexistent vegetation or if the present condition prevailed before human interference. It is also possible that neither of these alternatives represents the truth, since it is most likely that dry, spiny forest and shrubby vegetation have always co-existed, depending on local physical conditions. Never- theless the evidence is that the forest had a larger area than today and that their reduction has been due to human influence. When northeastern Brazil was invaded or evolved by xerophytic species is a question with no answer so far, although the possible routes which were taken seem to be fairly well unders- tood. There is geological and biological evidence which indicates that past climatic fluctuations in the area forced caatinga back and forth with humid or semi-humid vegetation' (humid forest) temporarily replacing it. The remnant mouítain-top humid forests of today surrounded-by semi-arid caatingas are a testimony of the more widespread humid forests of the past (Andrade-Lima, in press). When such oscillations took place and how many times have they occurred is one more problem to be solved. It is possible there were as many as the glaciations. Despite these past increases in forest areas the greatest part of the Brazilian northeast is presently covered by a vegetation which no matter how complex it is, cannot be said to be a “forest vegetation” as a whole. Among caatingas of today, arboreous communities (thorn-deciduous-forest ) are a minority and it usually consists of a fairly open shrubby community which develops some undergrowth during the rainy season which cattle can feed upon. The previously mentioned mountain-top humid forests are important as water suppliers to the surrounding lands where a higher type of caatinga is to be found. Floristically caatinga is not a completely isolated vegetation type. Two or three examples can be given to illustrate this: Anadenanthera macrocarpa and Amburana cearensis occur also in the Chaco region, in northeastern Argentina and southern Paraguay; Cavanillesia cf. arborea belongs also to the flora of Acre (Western Amazonia), where one also finds a variety of Amburana cearensis; Tillandsia tricholepis occurs both in the caatinga and in Argentina and Rio de Janeiro, and many other places. Several other examples could be given and still more at the generic level. The present isolation of the area was possibly due to slow climatic change but the geological time when it took place is not yet clear. The area of caatinga vegetation The general area of the Northeastern caatin- gas (Figure 1) is about 834,666 km? and stretches from 2054ºS to 17021'S. One may think of three main boundary lines for-the caatingas: (a) to the cast, (b)to the north, and (c) to the west and southwest. The southern line is more complicated and needs further study. D. Andrade-Lima CAMPA GA: CP eniestgóica VS A INTERSTATE UMIT ao UM OF THE POLYGON —. RIVER Figure 1. The general area of the northeastem caatingas. 152 Nimer (1972) produced a revision of the climates of the Brazilian northeast, and an analysis of the climates of the caatingas by Reis (1975) brings to our knowledge not only the basic climatic factors for the area but also emphsizes the influence of orography on the succession of topoclimates along two transects across the northeast. Physical conditions The prevalence of a BSh climate in central and western northeastern Brazil is well known. Although it is not the only climate type peculiar to the region, it is, nevertheless, the climate responsible for the caatinga vegetation. Low and irregular rainfall and high temperatures are the main reasons for such climate. Basic studies to the understanding of the Northeastern Brazil climate are given by Andrade (1972) and Nimer (1972, 1977). The three regional rainfall regimes are | illustrated in figure 2 (Andrade 1972). By the time these air masses reach the Northeast they have lost most of their energy. Under these circumstances and from year to | year, the rainfall in the Northeast varies from 259.4 mm/year, in the Aspidosperma-Pilosocereus | community ( see page 158) centred in Cabaceiras, | Paraíba, to about 1000 mm in the Tabebuia- | Aspidosperma-Astronium-Cavanillesia community (Table 1) of south central Bahia and northern Minas Gerais. The rainfall in the northeast concentrates in a short period: “January-February in the west and south of the area, with the progression of the Ec; March-April in the north of the area, under the autumn oscillations of the doldrums” (Andrade 1972). This, however, does not mean that caatinga «eceives rainfall only during these months but rather that these are the months with greater precipitation, preceded by a short increase and foilowed by a short decrease in rainfall. Recently SUDENE has implanted a network of meteoro- E: logical stations which is already producing results for a better knowledge of the climatic conditions of the region. Caatinga vegetation grows in different types of soils, from deep, loose, sandy soils where the water-table during the rainy season probably comes close to the surface (sedimentary soils of the | Pilosocereus-Poeppigia-Dalbergia-Piptadenia . community — page 158) and sinks deep into the ground during the dry season, to the eroded soils E with intense run-off and little, if any, infiltration to a real water-table. SUDENE (1973) has published two maps on which ground water availability is illustrated. D. Andrade-Lima A good account of the soils of the semi-arid Northeast is given by Queiroz Neto (1972), but more detailed information can be found in the maps and reports of the DPP/DNPEA — DA/DRN, SUDENE. In the caatingas, during the dry season, the average monthly temperature is 26-279C (Andrade 1972), with a notable variation between day and night. During the rainy season the average tempe- rature is slightly lower. The maxima and minima temperatures vary greatly throughout the caatingas, with the highest ones registered in the state of Piauí and Western Paraíba. Little information in available on the histo- rical climatic fluctuations in the caatingas area. The present-day existence of mountain-top humid forest confirms that in previous times (not esta- blished) a more humid climate made possible the dispersion of some species from the northeastern coastal rain forest and/or southeastern mesophytic rain forest (Andrade-Lima, in press). Further evidence of more widespread humid forest under wetter climatic conditions is given by the fossil deposits of Boa Vista and Umbuzeiro, both in Paraíba. The former was first described by Muniz and Ramirez (1971). At these sites, which are in areas where the fossil remains are derived from species which grew in humid forest (Duarte 1979, Duarte & Vasconcelos 1980). Studies of these two deposits are still under way but it is already certain that the Boa Vista deposit is much older. Flora and vegetation Although fairly well known, the plant species of the caatingas have never been listed. In the third volume of his “Estudo Botânico do Nordeste”, Leutzelburg (1922-1923) presents a list of some of the plants he collected in the area, along with others he collected elsewhere (Rio de Janeiro, etc.). But this list is far from being complete. Vegetation maps of the caatingas are few and without details as for example those by Romariz (1972), Andrade-Lima (1966) and Veloso (1966) as a part of their Brazilian Vegetation maps. Duque's vegetation map (CNG/ETENE, s/d), dealing only with the northeast, comes closer to field reality but still is not sufficiently complete. Somewhat more detailed are those by Andrade- Lima (1960, 1964) for Pernambuco and a part of North-western Rio Grande do Norte. The maps by RADAM, with more details and more precise boundary locations, improve the situation for a small part of the caatingas. The rest of the caatinga is being mapped by RADAM and the results will be published in a short time. 153 The caatingas dominium “(CL6T 9Peipuv) UZeIg urseoyuou jo sowtão: |egures euolõos asmu aU “7 Ama NDA uai Mui SNIvis NANA dl VINON NMNLOY AA HAIA SNIVS BINANS SNIvy JO SIWIVIN PAN The caatingas dominium 155 first call the attention to the observer. Each type does not necessarily equal the others in size, economic value, or other factors. Some are rather rigid in composition whilst other allow quite a number of facies from place to place. In certain cases some small units are to be found within the larger ones. Perhaps twenty, thirty or even more type-communities exist in the caatingas, but it seems wiser at this stage to give only a condensed list of types, particularly since the meteorological se spo * Tão 2568 aso a q sy 3000 b p ho 7 se! 4 "0 e) AOS Ú ANNUAL ISOHYETS se fase AUTHOR: EDMON NIMER 1780 O 80 100 180 200280300 380 km [Rh ld ari Figure 3. The caatinga arca of figure | roughly covers the isohyet of 1000 mm. and pedological information which we need to look for correlations between physical factors and the vegetation is still incomplete. For the sake of conciseness only the generic names are used, being necessarily understood that they are not always represented by the same species. Although these 12 communities can be roughly recognized in the field (as well as other types not considered here) the actual distribution areas of these most widespread types is unknown. They do not occur as discrete units separated from each other by clear lines but gradually pass from one to another (particularly when climate is responsible for the variation) and reappear whenever the critical prevailling conditions are present. In those types which are more associated with the geology and soil, the change is frequently more distinct. The geological map of Brazil (MME, DNPM, 1971) and the soil maps (exploratory level) for most of the northeastern states help in the understanding of some of the vegetation types, as for example the Pilosocereus-Poeppigia-Dalbergia- Piptadenia or open arboreous caatinga type. Whilst this unit is, no doubt, partially dependent on climatic conditions it is also strikingly correlated with sedimentary rocks of the “Cipó series” (Almeida 1972) which result in the sandy soils between Petrolândia and Ibimirim in Pernambuco and adjacent areas of Bahia. The basic factor for northeastem vegetation is climate, essentially rainfall. The caatinga area of figure 1 roughly covers the isohyet of 1000 mm (Figure 3), inside of which the less than 500 mm isoline includes the poorest caatingas. Geopedolo- gical factors are a second step in the interpretation of plant landscape of the area. Nevertheless topoclimatic maps for the northeast are still to be prepared. Only macroclimatic ones are available in the literature anq, as a consequence, no correlation can be found between the given vegetation-types and climate. Somewhat better is the xerothermic- index map (Figure 4) in which the caatinga vegetation occupies roughly the area inside the i= 100 — 150 line. According to this map it would be possible to have three main vegetation-types integrating the caatinga vegetation, whereas if a macroclimatic map were to be used, and assuming, as it is usually said, that the typical climate type for caatinga is BSh, only one vegatation type would be available. The importance of geopedological factors is illustrated by the existence of two vegetation dominia within the area with the same xerothermic value (100-150), with caatinga on the eastern part of it and cerrado on the western one. This is strange on the view that climate is the main controlling factor of northeastern Brazil vegetation D. Andrade- Lima but can be explained on the basis of the geology of both subareas. In the east the rocks belong to the northeast nucleus ofthe Pre-Cambrian Brazilian Shield and they give rise to the mineral-rich soils required by most of the caatinga species. The western rocks, on the other hand, integrate the Parnaíba Basin where sandy mineral-poor soils are the more common ones, which happens also to be the case in many of the cerrados of Brazil. In the southern part of the i = 100150 area, with the general direction of the São Francisco river bed most of the low land rocks possibly belong to the ordovician São Francisco or Bambuí series where a dark grey limestone is common. The resulting soils support the number 1 vegetation- type of the list, which is here accepted as a caatinga-type no matter how tall and dense the forest is. At this point two undeniable conclusions spring up: a) vegetationtypes in the northeast result from a climate-soil integration and the number of combinations and consequent plant communities is fairly high; b) the amount of information about the physical factors (especially topo-climates) is not enough for any study at the plant-communities level. Under these circumstances an intermediate position seems to be the most suitable as presented in table 2. Description of the main caatinga-units Unit 1 — (Vegetation type 1: Tabebuia-Aspidos- perma-Astronium-Cavanillesia) This unit is accepted here as a member of the caatingas dominium. It might eventually be considered simply as a tall dry forest as some authors think but the reasons are sufficiently strong to stick to the first idea. Most or even all the trees shed their leaves during the dry period, putting them forth again only when the rains return, 5-6 months later. Besides, the floristics of these forests is not much different from that of other arboreous caatingas elsewhere. Genera and species such as Astronium urendeuva, Schinopsis brasiliensis, Tabebuia avellanedae, Cereus jamacuru, and Pterogyne nitens, quite common in unquestion- able caatinga areas, are also frequent there. Cavanillesia arborea with its huge barrel-trunks abounds in this unit and is well represented in the non-caatinga forests of northem Espírito Santo. Such a presence could argue against the inclusion of Unit | within the caatingas, but the same species is also found in typical caatinga communities óf medium Rio de Contas, as well as in low lying areas between Jequié and Contendas do Sincorá, bothin the state of Bahia. | 158 D. Andrade-Lima Table 1. Caatinga-Types 1. Tabebuia-Aspidosperma-Astronium-Cavanillesia 2. Astronium-Schinopsis-Caesalpinia 3. Caesalpinia-Spondias-Bursera-Aspidosperma 4. Mimosa-Syagrus-Spondias-Cereus 5. Pilosocereus:Poeppigia-Dalbergia-Piptadenia 6. Cnidoscolus-Bursera-Caesalpinia 7. Caesalpinia-Aspidosperma-Jatropha 8. Caesalpinia-Aspidosperma 9. Mimosa-Caesalpinia-Aristida 10. Aspidosperma-Pilosocereus 11. Calliandra-Pilosocereus 12. Copernicia-Geoffroea-Licania open shrubby caatinga; small, tall caatinga forest; northem Minas Gerais and southern central Bahia. median caatinga forest; most of the central area of the Dominium. median caatinga forest; à little drier area than the preceding. low caatinga forest; northem central Bahia. low caatinga forest; sandy soils from the Cipó series and similar ones. open arboreous caatinga; southwestemn Ceará, and other medium dry areas with loose, acid soils. shrubby caatinga; drier areas in the São Francisco valley. open shrubby caatinga; Cariris Velhos, Paraíba. open shrubby caatinga; Seridó, Rio Grande do Norte and Paraíba open shrubby caatinga; Cabaceiras, Paraíba. tered art s with gravelly soils restricted. fringe caatinga forest; river valleys of Piauí, Ceará and Rio Grande do Norte; restricted. Magalhães and Ferreira (1976) share the same opinion in their study on the plant cover of the Jaíba region in the state of Minas Gerais. Both the subdeciduous and deciduous forests described by these authors include a high pro- portion of genuine caatinga species, although the moderate dryness of the area allows some mesophytic species to grow along in a natural gradation. The community is fairly dense, up to 25-30m high and at least 3 storeyed. In addition to the already named caatinga species one also finds Anadenanthera macrocarpa, Bursera leptophloeos and Aspidosperma pyrifolium. The most conspicuous species at Jaíba is Cavanillesia arborea which, according to Magalhães and Ferreira (1976) is associated with the soil class Cambissol eutropític, (ímestone substratum phase. Ratter et al. (1978) describe a similar arboreal caatinga in the Januária region of Minas Gerais. The rainfall in the area of the Unit 1 varies from 850 mm to about 1000 mm and nebulosity is most of the time low. A few years ago a very large part of this unit in Bahia was cut over for grass cultivation. Unit II — (Vegetation types 2, 3, 4 and 6; Table 1) Unit II is a typical caatinga forest, characte- rized by a not too dense arboreous stratum, 7-15m tall, with many thorn bearing species. The ground cover is frequently sparse, unless formed by species of Bromelia. Grasses are almost absent and Sida, Melochia, small Cassia, and a few Portulaca are the most common among the undershrubs and herbs. Species of Cactaceae occur here and there, especially Cereus jamacaru, several Pilosocereus and Opuntia palmadora, the latter always below open areas in the canopy where more light penetrates. Because four vegetation-types (2, 3, 4 and 6) were put together under this unit (Table 2), variations in height, density and composition are to be found. Astronium urundeuva | and Schinopsis brasiliensis, together or isolated, are the most conspicuous species in the community, but seldom forming dense stands. On heavy rich soils (from basic rocks?) there is a tendency for the dominance of Astronium. Two species of Caesalpinia, C bracteosa and C pyramidalis, cover a good percentage (exact extent is not known) of the area, but they never grow so high as Astronium and Schinopsis Spondias tuberosa is more frequent in not too heavy soils with a good drainage. Aspidosperma pyrifolium requires higher temperatures and less humidity. Ziziphus joazeiro usually occurs in places where ground water is more available (river valleys or wherever water stays longer in the ground). Bursera leptophloeos is the really eurioiceous species, growing in about two thirds of the caatingas. Cnidoscolus phyllacanthus thrives better in the drier parts of this unit in soils derived from crystalline rocks. Anadenanthera macrocarpa, Amburana cearensis, Piptadenia zehntneri, Mimosa spp. also belong to this unit. The caatingas dominium In northem Bahia, on fairly well drained soils, at altitudes between 300 and 600 m, with an average annual rainfall of about 800 mm, this unit is enriched by Syagrus coronata. The original vegetation has for many years been disturbed by agriculture but the uncut Syagrus palms give evidence of its previous existence. In the states of Rio Grande do Norte and Ceará, this unit presents a facies (which may be an independent unit of its own to be recognized after further studies) in which Auxemma oncocalyx is one of the dominant species. In all these cases Unit IL has always been severely damaged by human destructive action, especially by agricultural use, timber extraction, and charcoal production. Unit II — (Vegetation type 5: Pilosocereus- Poeppigia-Dalbergia-Piptadenia) This is a quite distinct type of caatinga growing on deep, sandy soils derived from the Cipó series in both Pernambuco and Bahia. The rainfall in the area is around 500 mm/ year but the soil permeability reduces the utilization of the water by plants and animals. Surface drainage in the area is only seen during the peak of the rainy season through a small number of rivulets. The vegetation is a low (5-7 m) caatinga forest in which the leafy plants present slender Table 2. Caatinga Units and somewhat upright branches with small leaves and leaflets in such way that light easily passes through. Above the general canopy emerge the upright blackish branches of Pilosocereus cf. piauhiensis. This landscape stretches on mono- tonously over an undulating surface eroded from the cretaceous sediments. Among the tree species, Poeppigia procera, Dalbergia cearensis, Piptadenia obliqua, Bursera leptophloeos, Anadenanthera macrocarpa and Acacia bahiensis are the most representative and Mimosa verrucosa, Waltheria ferruginea, Cratylia mollis, Cassia acuruensis, Pilosocereus tuberculatus are the most common shrubs. Among the ground plants it is worthwhile naming Hohenbergia caatingae which stores water among its leaf-bases upon which small animals can satisfy their moisture requirements. The not too distant caatingas of the Raso da Catarina, in northern Bahia, also belong to this unit. One of its peculiarities is an Annona sp. with edible fruits. This family is poorly represented in the caatingas as a whole. Unit IV — (Vegetation types 7,8,9 and 10; Table 1) It is difficult to determine if this is a natural or a man-induced unit. It occupies the largest area today and can be found throughout the caatingas Dominium. Typically Unit IV grows on soils derived Caatinga-Types Caatinga-units (Physical basis) Physiognomy Observations 1 [1=100-150 1, (South) mainly Bambui Tall caatinga forest Browsing vegetation group, limestone rocks 1, (East) predom. p.C. Tall caatinga forest Browsing vegetation crystalline rocks 2,3,4,6 Il:i=150-200 mainly p.C.crystalline rocks | Median and low caatinga Great variability within. forest, and open Perhaps not browsing vegeta- arboreous (woodland?) tion, in previous times but so - caatinga under human long lasting influence. Utilization only during the rainy season. E] 150-200 Cipó series sandstone rocks Low caatinga forest Poor ground vegetation (both grasses and forbs); browsirg vegetation;with surface water limitation. Utilization only during the rainy season. 7,8,9,10 IV: i= 200-300 mainly p.C.crystalline rocks Tall to low Grazing land; storage-water and shrubby caatinga necessary; great surface ero- 150-200 sion problems. Utilization only during the rainy season. n V:i=150-200 mainly p.C. metamorphic Low shrubby caatinga Poor grazing land; too locali- rocks zed to be taken under consi- deration. 12 VI:i=100-150 mainly alluvial soils along Valley caatinga Not grazing land, but someti- and river valleys palm-forest mes used as à water resource, 150-200 during the dry season. The caatingas dominium But it was soon realized that the richness of those pastures disappeared during the dry periods and although the dry climate was favorable to the cattle's health, many of them died from thirst and starvation. Cactaceous plants, especially Cereus jamacaru, after being passed over fire to burn off the spines, were used as water and food. The number of cattle farms was reduced as cotton cultivation occupied much of the area with better soils. Later Indian cattle were introduced to improve production and spineless cactuses (Opuntia ficusindica and Nopalea cochenillifera) were planted to provide food during the dry season. Forage grasses were planted in areas of better soil but not always with much success. Under these circumstances the area of the caatingas was almost entirely occupied but with a sparse population. Denser population developed only in humid valleys where a more intensive agricultural system was possible. On the farms beef-cattle used to be the basic activity. Running free in the unfenced caatingas they had to be brought together every year during the rainy season to be branded, counted and sold. The present situation is not much different in the drier areas. But in areas with a xerophytic index of i=100-150, as in Western Alagoas, the stock have been changed to dairy cattle which are kept within fenced plots and fed with Napolea, Opuntia, planted grasses and supplemented by free grazing. In Central Bahia, whenever possible, Indian beef-cattle are raised in fenced areas planted with Panicum maximum with good results. In farms where cattle breeding is the sole activity the required number of laborers is small and most of the young men move out to the towns. Although in smaller numbers, women also go to towns to look for jobs, education, etc. Throughout the caatingas the family unit is strongly held together and man has became well adapted to the severe environment. Their attitudes are quite different from those of people of the humid forest zone. With the development of a good road system the diet in the towns of the caatingas region suffered some modification with products brought from the main cities. On the farms, however, the same basic diet has been kept almost with no change: dried meat, beans, rice, manioc or cassava flour, com, sugar as sugar-brick (“rapadura”) and sometimes sweet potatoes were and still are their staple food. Most of these products originated from the farm or surrounding area. Fruits were not much used in the cattle-manºs diet. Orange, banana or perhaps papaw would be the most important fruits utilized. Those who live in the caatingas away from the influence of the towns are healthy. Sometimes bubonic plague occurs but only in higher places with cooler and more humid conditions of the mountain forest environment not in caatinga proper. Chicken-pox and measles are typical diseases of youth with less drastic consequences. Rats (carrying fleas) are responsible for the bubonic plague. In the caatingas there is no nomadism in the ordinary sense. Farms which were established many years ago usually still belong to the same family. When sold most of the previous owners move to town. Usually the dry season in the caatingas coincides with the sugar cane planting period of the coastal humid zone. At this time many young people go to the coast to work until the next rainy period in the caatinga. In the caatingas, under the extensive grazing system, the land owner often does not live on the farm. He lets the “vaqueiro” (cowboy) take care of almost everything who in return raises his own cattle as well as those of the owner. The payment system may change from place to place but most commonly he receives a small salary plus one out of every four or five bom calves. The interrelationship between farmer and laborer is quite friendly and respectful. The farms in the drier area of the caatingas are usually large (1000-3000 ha) considering the low productivity under such restricted conditions. The carrying capacity of these areas is considered to be around 1 head/10 ha. Usually the cattle are kept on the same farm all year round. The recent introduction of techniques such as drilling wells for deep water and the cultivation of Opuntia and Nopalea with their water storage capacity, Prosopis juliflora and grasses, have made this use much more possible. In some cases the farmer owns a farm in the low caatingas for the rainy period and another one on high grounds, where due to altitude and related facts humidity is always higher, for the dry season. A comprehensive study of the forage possibilities of the caatinga has not been done yet. As grasses appear in such a minority and generaliy speaking forbs are not densely represented in the caatingas, browsing on trees and shrubs is the most dependable utilization of the vegetation. Among the grasses Chloris orthonoton, Paspalum spp., Cenchrus echinatus (before fruiting), Tragus berteronianus and Brachiaria plantaginea are frequently found. In the drier areas these are substituted by species of Aristida such as A. adscensionis and A. eliptica with the great disadvantage that only in the first stages of growth cattle use them. From then on they become too hard. D. Andrade-Lima As for the forbs, the Malvaceas such as Herrissantia tiubae, H. crispa, Sida cordifolia and 5. galheirensis are the most common; less frequent are: Portulacaceae: Portulaca grandiflora, P halimoides and eventually Talinum patens; Amaranthaceae: Alternanthera spp. and Gomphrena spp.; Leguminosae: Phaseolus martii, Ph. bracteatus andin places with more sandy soils Ph. panduratus, only to give some examples. Browsing species belong to different families: Leguminosa Cuesalpinia pyramidalis and C. bracteosa, Bauhinia cheilantha, B. heterandra; Cathormium multi. florum, Cratylia mollis and several others; Boraginaceae: Cordia leucocephala The wild Cactaceae can only be used after burning away the spines. The substitution of these natural forages by cultivated ones such as Cactaceae, Leguminosae and Gramineae is greatly limited by climatic reasons. Food crops usually do not compete with cattle. Cotton is the principal cash crop which has entered the cattle areas. The common use of putting the cattle into the cotton field after harvesting brings some compensation. Recovery of the caatinga ecosystem - The use of the caatingas under extensive Brazing and browsing with an animal population superior to the carrying capacity for so many years has resulted in the nearly complete destruction of the ecosystem. Conscious of this fact, the Brazilian Government through its agency EMBRAPA (Empresa Brasheira de Pesquisas Agropecuárias) is developing, besides many others, a program aiming at the stabilization of the cattle/vegetation/soil system before desertification - becomes too advanced. 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