Several authors have analyzed the economic viability of using wood from Cerradovegetation to manufacture charcoal for the steel industry, including Oliveira et al. (1998, 2002) and Rezende et al. (1986). In these studies, economic analysis followed a deterministic approach based on classic methods of investment analysis that include Net Present Value (VPL) and Internal Rate of Return (TIR).
Plants bearing extrafloral nectaries are widespread amongst the woody flora of Bra- zilian cerradovegetation. A diverse assem- blage of nectar-gathering ant species visit these glands both day and night and may act as anti-herbivore agents, significantly reduc- ing herbivore damage on vegetative as well as on reproductive plant parts. The outcome of such facultative mutualistic associations, however, may vary both geographically and temporally and may be also conditioned by diverse factors such as the species of visiting ant and the escape tactics of the associated herbivore species (Koptur 1992, and included references). Future research on ants and EFN- bearing plants in cerradovegetation should take into account other factors that may pos- sibly also affect ant-derived benefits to the plants . For example, the degree to which her- bivore deterrence by ants can be translated into greater fecundity (i.e., increased number of fruits and seeds) by a given nectary plant species may vary with traits such as the plant’s habit (shrub versus tree) and fruit type (dry versus fleshy fruits), as well as with soil nu- trients. Although there is evidence suggest- ing that such factors may condition the out- come of certain ant-plant systems in the cerrado (Del-Claro et al. 1996, Oliveira 1997), additional experiments are needed in order to better understand the dynamics of such mutualistic interactions in this vegeta- tion type.
C stocks of native vegetation between our study and that of Corazza et al. (1999) and of Jantalia et al. (2007) can be attributed to the heterogeneity of the Cerradovegetation in the experimental area of Embrapa Cerrados at different geographic coordinates (Table 5: footnote). At the Embrapa Cerrados site, the physiognomies “Cerradão”, a forest vegetation where Corraza et al. (1999) collected soil samples, and “cerrado sensu stricto”, a typical savanna vegetation (consisting of trees, shrubs, and grass layers), can be found. In addition, 20 years earlier there were no protection programs against fire and accidental burning, which may have caused variations in the biomass and soil C stocks and interfered with the differences between the values of the first and last evaluations. In the case of different Cerrado physiognomies, the amount of C stored in soils under NV can vary from 87 to 210 Mg ha -1 C (Bustamante et al., 2006).
The study area is a well-preserved, 5,000-ha area. How- ever, it is surrounded by degraded areas and roads and is heavily affected by city lights, which generally decreases sampling suc- cess when using light traps. Nevertheless, the richness of Arctiinae in the Jardim Botânico de Brasília can be considered high. The tiger moths in the reserve represent 9% of the 723 known spe- cies of Arctiinae in the Cerrado (F ERRO et al. 2010), 5% of the 1,391 known species in Brazil (F ERRO & D INIZ 2010), and 1% of the 5,931 Neotropical species (H EPPNER 1991). An extensive study
The study area is located in the Campos da Mantiqueira region, in the southern part of the State of Minas Gerais, Brazil (Figure 1a). The area comprises dissected plateaus along the northwestern rims of the Mantiqueira Range. The climate is tropical humid, with mean annual temperature and precipitation of 19.2 °C and 1,435 mm, respectively (Chagas et al., 1997). The native vegetation is typically Cerrado on Oxisols. The rainy season is from November to April, making up about 80% of mean annual precipitation. Potential annual evapotranspiration is 888 mm, with an annual water deficit of 53 mm. The dominant soils are Oxisols on flatlands and gentle slopes, developed from mica-schists of the Andrelândia Group, aged 540-1,000 Myrs (Ribeiro et al., 2003). The dip angle of strata of these rocks varies randomly in the region, alternating between horizontal and inclined orientation.
The cerrado is the Brazilian savanna vegeta- tion and it encompasses a core area in Central Brazil (most of Mato Grosso, Mato Grosso do Sul and Tocantins; Goiás; western Minas Gerais and Bahia) and the peripheral areas distributed throughout north Brazil, northern and south (small parts of São Paulo and Paraná), and extending to Bolívia and Paraguai (Ferri, 1977; Ratter et al., 1997). The cerrado is very varied in form, ranging from dense grassland, generally with a sparse covering of shrubs and small trees (“campo cerrado”), to almost close woodland with a canopy height of 12-15 m (“cerradão) (Ratter et al., 1997). The cerrado climate is defined by a strong dry season during the winter (nearly from April to September). Since seedlings are very sensitive to water stress, one supposed that the cerrado climate was a limiting factor for sexual reproduction of cerrado species, favouring vegetative propagation. However, it has been shown that sexual reproduction and seedling establishment are common features in the cerrado and involve adaptation mechanisms to this environment (Oliveira, 1998). For example, Labouriau et al. (1964) reported seeing seedlings of a number of species in cerradovegetation in São Paulo, Minas Gerais and Goias. The authors express the need for more research on seed biology of cerrado species to acquire more general ecological propositions in the cerradovegetation.
especially in the Brazilian Central Plateau (Ratter et al., 1997). The cerradovegetation is not uniform in physiog- nomy, ranging from grassland to tall woodland (Coutinho, 1990), but with most of its physiognomies within the range defined as tropical savannas. Hyperseasonal cer- rado areas normally appear in interfluvial regions with poorly drained soils (Sarmiento, 1983), being very re- stricted within the Cerrado domain, whose cerrado areas are almost seasonal. Nevertheless, Batalha et al. (2005) found a small area, composed of cerrado species, which is the first occurrence of a hyperseasonal cerrado, in Emas National Park (ENP), central Brazil.
ABSTRACT – (Variation in plant defenses of Didymopanax vinosum (Cham. & Schltdl.) Seem. (Apiaceae) across a vegetation gradient in a Brazilian cerrado). Cerradovegetation is composed of a mosaic of vegetation types, from campo sujo, dominated by herbs; campo cerrado and cerrado sensu stricto, with shrubby vegetation; to cerradão, with trees forming a denser forest. This physiognomic mosaic is related to differences in the water availability in the soil. Cerrado plants are considered physically and chemically well defended against herbivores, but there are no studies showing how plants allocate investment to various types of defensive mechanisms in different habitat physiognomies. The defensive mechanisms and the nutritional traits of a cerrado plant, Didymopanax vinosum (Cham. & Schltdl.) Seem. (Apiaceae), were compared along a vegetation gradient. Toughness, as well as water, nitrogen, cellulose, lignin, and tannin contents were measured in young and mature leaves of D. vinosum collected in campo cerrado, cerrado sensu stricto (s.s.) and cerradão. Plants from cerrado s.s. and cerradão were of better nutritional quality but also had higher tannin contents than campo cerrado plants. Some type of compensation mechanism could have been selected to provide an optimum investment in defense, according to limitations imposed by water deficits in the habitat.
ABSTRACT - Although very abundant in the Neotropics, there is little information about the biology, ecology and natural history of Brazilian Chlamisinae beetles. In the present study we investigated directly in the Cerradovegetation the aspects of natural history and biology of Chlamisus minax Lacordaire. The results showed that the species has annual cycle and the adults are present in the field during the spring and summer when the reproduction occurs. The females cover their eggs with a mantle, and later on the rests of the egg and faeces are added by the larva to the mantle to produce a protective case. The six larval morpho-stages are herbivorous and feed on floral buds of Heteropterys pteropetala A. Juss. (Malpighiaceae). The larvae pupate in the host plants and after that they fall on the ground remaining in diapause between April and October. This is the first study to investigate the biology and natural history of a Brazilian Chlamisinae beetle directly in the field.
Lactiferous plants are common in the Brazilian cerradovegetation. Evidence has shown that they suffer less from herbivory than other plant species (Lewinsohn, 1991). Latex may work as a plant defense mechanism against insect herbivores. Many lactiferous plants have secondary compounds in the latex, such as alkaloids and terpenes, functioning to deter foliage-eaters. Latex might also cause other adverse effects on insects, as it is sticky and hardens when exposed to air (Bernays & Chapman, 1994; Farrell et al., 1991). However, insect herbivores have ways of circumventing this defense mechanism. For example, insect herbivores may show specific behavior to sabotage latex defense, such as cutting latex canals in the most distal part of the leaves and then feeding on these leaves (Dussourd, 1993; Bernays & Chapman, 1994).
In the Brazilian cerrado, some studies have used Raunkiaer's system to classify the sampled species in life-forms. For instance, Mantovani (1983) classified a cerrado site flora in life-forms, cons- tructed its biological spectrum, and compared it with other cerrado spectra obtained from Warming (1892) and Ratter (1980). Batalha et al. (1997) and Ba- talha & Mantovani (2001) carried out floristic surveys in two cerrado sites and also classified the species in life-form classes. In all these sites, higher proportions of hemicryptophytes and phanerophytes were found. The cerradovegetation comprises a wide physiognomic range, from grassland to woodland, but with most physiognomies fitting the definition of tropical savannas (Coutinho, 1978). Since the importance of trees and shrubs increases from open to closed physiognomies (Coutinho, 1978), the proportion of phanerophytes also increases in this direction.
We recorded 63 gall morphotypes on 47 host plant species belonging to 22 families in the vegetation along the Jacaraci trail (Table I). Of the total number of galls (63), 17 were observed in the Gallery forest (on 14 plant species of 9 families) and 46 in Cerradovegetation (on 33 plant species of 16 families). The plant families with the greatest gall richness were Leguminosae (Fabaceae) (n=15), Myrtaceae (n=9), and Asteraceae (n=7). The Leguminosae had the largest number of host species (nine), followed by Myrtaceae and Malpighiaceae (seven and five species, respectively). Bauhinia L. (Leguminosae- Cercidoideae), Mimosa L. (Leguminosae- Caesalpinioideae), Guarea F.Allam. ex L. (Meliaceae), and Eugenia L. (Myrtaceae) were the genera that hosted the greatest number of galls (6, 3, 3, and 3, respectively). The species showing the greatest gall richness was Mimosa gemmulata Barneby, with three associated morphotypes.
The Brazilian savanna, or the Cerradovegetation, is comprised of a mosaic of physiognomies that vary from open fields to closed woodlands. But unlike the typical Cerradovegetation, known as Cerrado sensu stricto (s. str.), where shrubs and small trees are subjected to a lengthy (five months or more) and severe dry season, riparian and gallery forests present high soil water availability throughout the year (Kissmann et al., 2012). This arises because, in Cerrado areas, riparian forests occur along medium (10-20 m in width) and large (> 20 m in width) rivers, and gallery forests occur along small (< 10 m in width) rivers and streams (Oliveira-Filho and Ratter, 2002). This condition provides a suitable habitat for a large number of typical moist forest species (Oliveira-Filho and Ratter, 2002). Therefore, depending on microhabitats formed by the uneven topography along and perpendicular to watercourses, this high moisture in the soil facilitates the occurrence of species with different soil water requirements (Toniato et al., 1998; Marques et al., 2003; Teixeira and Assis, 2005).
Comparative studies of the woody vegetation of rocky outcrop and typical cerrado sites can aid in evaluating the effects of edaphic conditions on their floristic compositions and structures. Floristic and phytosociological surveys are important vehicles for increasing our knowledge and understanding of the woody flora of rocky outcrop cerradovegetation, especially in light of the fact that this phytophysiognomy has been well described (Ribeiro & Walter 2008) but its community structure, spatial distribution, and interactions with the abiotic environment are not yet well understood. Rocky outcrop cerrado physiognomies have apparently been less impacted by anthropogenic activities as its stony nature makes crop cultivation nearly impossible (Machado et al. 2004). This situation increases the importance of floristic and structural analyses of the vegetation structure of rocky outcrop cerrado sites in elucidating interactions between vegetation formations and edaphic factors as well the role of this vegetation in maintaining the floral diversity of the Cerrado biome as a whole.
especially in the Central Highlands (Ratter et al., 1997). Disjunct areas also occur in other States, such as São Paulo (Ratter et al., 1997). The cerradovegetation presents a wide physiognomic variation. According to the “forest-ecotone-grassland” concept (Coutinho, 1978), the cerrado ranges from campo limpo, a grassland, to cerradão, a tall woodland. The intermediate physiognomies (campo sujo – a shrub savanna, campo cerrado – a savanna woodland, and cerrado sensu stricto – a woodland) are considered ecotones of the two extremes. Since the limits among cerrado physiognomies are not well-defined (Goodland, 1979), all subdivisions of cerrado are more or less arbitrary. Even yet, there is no agreement on the cerrado physiognomic subdi- vision. For example, besides Coutinho’s classi- fication, there are other systems, such as those of Eiten (1979) and Ribeiro & Walter (1998), in which the cerrado subdivision is even more detailed.
dominated Cerrado formations are gradually replaced by tree-dominated Cerrado formations. This corresponds to the fact that some Cerrado trees are very deep-rooting (Eiten, 1972). Under otherwise comparable conditions, soil fertility should also play a role for the distribution of the vegetation forms and certainly has an influence on the phytosociological composition of the Cerrado (Goodland & Pollard, 1973; Alvim, 1996). In conclusion, tree density rises with increasing plant-available water content provided that good internal drainage conditions a well aerated solum which does not impose physical resistance (e.g. waterlogging, laterite, bedrock) to deep rooting. The Mata de galeria is restricted to the effluents with directed runoff and occurs on deep, well-drained, and possibly more fertile soils. Plants of the Mata de galeria, which floristically belong to the mesophytic Atlantic forest biome (Eiten, 1972), have access to water from the capillary fringe of the stream and are therefore less exposed to drought during the dry season. Apparently, Cerradovegetation cannot compete with the gallery forest under these circumstances. Similarly, Emmerich (1989) reported that this feature can be observed on the intra-montane planes west of Brasília (Cerrado biome), where additional water (and possibly nutrients) from the surrounding slopes allows mesophytic forest to thrive. The centers of these planes, where the groundwater level reaches its minimum are, however, dominated by dense Cerrado.
and occupies a 1225,000 ha area at 590 to 740 m altitude. The region, according to Köppen’s Cwag climate type classification, has well-defined seasons: a wet season from November to April, with a mean rainfall of more than 1200 mm, and a dry season from May to October with a mean rainfall of 485 mm. Mean temperature ranges from 17 °C in June to 25 °C in January. There are several intermixed physiognomies in this vegetation patch, including mainly campo cerrado, cerrado s.s., and cerradão. Campo cerradovegetation is open, dominated by herbs, shrubs, and some sparse trees. Cerrado s.s. is a more dense vegetation, with an arboreal stratum and a dense stratum composed of herbs and shrubs. Cerradão has few herbs and shrubs under a well-developed arboreal stratum.
29 intensity (Bagchi and Ritchie, 2010). Species possessing traits such as high investments in structural tissues, physical defenses and production of secondary compounds to avoid herbivory may thrive in communities with high grazing pressure (Díaz et al., 2007). In another study conducted at the Caatinga, grazers were able to exclude plant species that are less tolerant to trampling and are more palatable (Severino and Albuquerque, 1999). Therefore, grazers could decrease palatable species abundance and consequently increase the success of unpalatable species as occurred in other drylands of Africa (Hanke et al., 2014), Israel (DeMalach et al., 2014) and Australia (Dorrough and Scroggie, 2008). Most plots with high animal load at the reserve investigated here are dominated by shrub species with low palatability such Calliandra depauperata, Pavonia varians and Croton sonderianus. These plant species have lower height and diameter which, combined with the smaller number of tree individuals, decreases average vegetation height and total basal area of the community.
No Distrito Federal estão reunidas excelentes condições para implantação de um programa desse tipo, uma vez que estão presentes importantes instituições de pesquisa; um acervo representativo da biodiversidade do cerrado; uma área urbana tombada como patrimônio cultural da humanidade; nascentes das principais bacias hidrográficas brasileiras e situações críticas em função do acelerado processo de ocupação das terras. De todas as reservas da biosfera existentes, a Reserva da Biosfera do Cerrado – Fase I é uma das poucas que possuem a peculiaridade de ocupação humana numerica- mente significativa; além de incluir cidades, unidades de conservação, setores agrícolas e diversificada rede de ensino e pesquisa, possibilitando seu acompanhamento a partir de um marco zero, final dos anos 50 e início dos anos 60.
There was a larger variation concerning floristic composition and species abundance between the wet grassland and both cerrados, reflected in the first ordination axis and related to larger amounts of clay, organic matter, phosphorus, aluminium saturation, aluminium, and potassium in the wet grassland. Constant waterlogging in this vegetation form causes hypoxia or anoxia, which is the main limitation that reduces root aerobic respiration and the absorption of minerals and water (Baruch 1994), and consequently decreases decomposition rates and increases the amounts of organic matter in the soil (Crawley 1997). Indeed, wet grasslands are generally related to larger amounts of organic matter (Critchley et al. 2002). Clay, as colloidal component of the soil, is related to base adsorption and, consequently, is important for the vegetation (Ellis and Mellor 1995). Wetland communities in Belize also appeared on soils with increased amounts of clay (Bridgewater et al. 2002). Under waterlogging, there is also an increase in aluminium concentration (Sistani et al. 1999) and reduction of ferrous ions that indirectly increases phosphorus and potassium concentrations (Gopal and Masing 1990).