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A one-stop location for information on big-leaf mahogany (Swietenia macrophylla, Meliaceae)

BOTANICA

Aerial view of woody cerrado with gallery forests east of Redenção.
Cattle Herd
Aerial view of woody cerrado with gallery forests east of Redenção.

The following page describes floristic patterns within the study region and at the Marajoara field site. The most frequent or dominant tree species are profiled based on field inventories & notes accumulated over many years. Use the links below to jump to the section of interest.

Click for section:

  • Regional Forests
  • Forests at Marajoara: First Impressions
  • Forest Structure & Composition
  • Summary
  • Species Descriptions
  • REGIONAL FORESTS

    Cerrado vegetation at ground level east of Redenção, with afternoon thunderstorm brewing.
    Cattle Herd
    Cerrado vegetation at ground level east of Redenção, with afternoon thunderstorm brewing.

    Forests and the grassland ecosystem called cerrado interdigitate along an irregular northeast-to-southwest zone across the eastern end of the study region, in complex patterns shaped by soil water and nutrient status and dry season fires. This transition zone is extremely fluid, and may be easily observed – closed forest abutting open grassland – or obscured by intermediate zones of cerradão, a shrubby, closed-canopy, woody community whose composition, while showing some forest affinities, is dominated by fire-tolerant cerrado species. Forests extend east and south into cerrado as galleries along larger water courses, and as isolated closed-canopy islands associated with drainage. Cerrado and cerradão formations likewise occur as isolated patches within closed forest, gradually diminishing in size and frequency moving north and west towards the Xingu River. Mahogany does not occur in cerradão or cerrado formations, nor to any great extent in gallery forests along seasonal streams penetrating their midsts.

    Forests here are evergreen with a deciduous component. Deciduous forests as reported by Ratter et al. (1973) from north-central Mato Grosso apparently do not occur within the study region, probably for lack of suitably fertile soils. At the regional scale forest structure grows taller and more complex moving from the southeast to the northwest, where annual precipitation totals are higher. Forests in the vicinity of Redenção have low (12–24 m), highly irregular canopies and extremely dense, predominantly non-woody groundcover; they are essentially two-storied, with frequent patches of nearly impenetrable vine forest. Nearing São Felix on the Xingu River, high forest overstories are punctuated by emergent trees exceeding 50 m tall. In between, high plateaus harbor extensive cerrado formations, as can be seen on the eastern portion of the Kayapó Indigenous Area.

    Dense woody vegetation with grass in a small patch of cerradão at Marajoara.
    Cattle Herd
    Dense woody vegetation with grass in a small patch of cerradão at Marajoara.

    Woody species diversity increases moving northwestwards across the study region. Local dominance by individual or small groups of species in closed-canopy forest is common, with stands grading into other formations according to relief, soil type, drainage, and use history. Patches of vine forest may coalesce into extensive tangled stands that may mark indigenous agricultural fallows or sites where fire destroyed forests on a large scale. Palms are important components of all forest stories, with babaçu (Attalea speciosa) and inajá (Attalea maripa) occurring at high densities across extensive areas.

    Several excellent studies of community-level changes in vegetation across soil catenas were conducted in the early 1970s in the Xavantina-Cachimbo region of northeast Mato Grosso. These researchers concluded that species composition is a good guide to soil nutrient status, with evergreen communities differentiating clearly between hydromorphic and dystrophic soils. Seasonally dry forests in this region are evergreen and small-statured compared to forests in the interior Basin, with canopies 18–23 m tall punctuated by scattered emergent trees including species present within our study region (e.g., mirindiba (Buchenavia capitata, Combretaceae), amarelão (Apuleia molaris, Caesalpinioideae), and mangue (Trattinickia burseraefolia, Burseraceae)). Many species listed by these authors are common to study sites in southeast Pará.

    FORESTS AT MARAJOARA: FIRST IMPRESSIONS

    Green traces drainage seepages on the eastern portion of the Kayapó Indigenous Area in the early dry season.
    Cattle Herd
    Green traces drainage seepages on the eastern portion of the Kayapó Indigenous Area in the early dry season.

    From the open vantage-point of pastures that dominate the landscape between Redenção and Marajoara, two features stand out: occasional boulderfields or exposed bedrock that emerges on higher ground or along incised banks of seasonal streams, and consistent transitions in the color and texture of soils across slope gradients. Loggers say that bouldery landscapes, especially on low ground near streams, were the best sites to find dense stands of large mahogany trees. Exposed Brazilian Shield bedrock demonstrates how variable soil depth can be in this region, from less than one to more than 10 m deep, compared to soil profiles many tens of meters deep in the alluvial Amazon Basin.

    Standing water is common in low-ground forest at Marajoara during the rainy season. Here, a small oxbow off the Grota Vermelha.
    Cattle Herd
    Standing water is common in low-ground forest at Marajoara during the rainy season. Here, a small oxbow off the Grota Vermelha.

    Low ground is always traced by seasonal streams. Flow rates are typically gentle, given the landscape’s overall slight relief, but larger streams can develop considerable force after heavy rainstorms; these may show signs of lateral migration, cutting banks 1–3 m deep and stranding oxbows in their wake, creating pools of standing water during the wet season. Early wet season rainstorms flush accumulated litter from larger streambeds in a sudden annual pulse. Through the first month of wet season flow, non-stormflow streamwater is strongly tea-colored from tannins leaching out of unflushed litter in low-order streambeds. Streams flow turbid – a pale milk chocolate color – during and shortly after rainstorms; between rains, as stream levels fall, streamwater clears. Though large-scale overland flooding by seasonal streams is uncommon in closed forest, larger streams may spill their banks after especially heavy or prolonged rainfall, depositing a film of sediment on adjacent low ground in their wake. (By contrast, storm-related overland flow is common where large tracts of forest have been converted to pasture.) A diverse aquatic community migrates to the heads of the smallest streams each year, including stingrays, caymans, and giant otters in larger aseasonal streams.

    At the height of the rainy season the low-ground landscape is a waterlogged one. Flowing streams are often flanked by adjacent flats characterized by marked micro-topographic relief, a faint pattern of pits and mounds lending the impression that a forest-wide blowdown has recently occurred even though no other physical evidence may remain – no tangle of decaying trees lying on the ground, or upturned root masses. Pits may fill with standing water for days or weeks depending on rainfall patterns. Mudholes are common, especially at catchment heads, at least in part created and maintained by wallowing white-lipped and collared peccaries (Tayassu pecari, T. tajacu) and tapirs (Tapirus terrestris).

    Miguel Alves de Jesus crossing the swollen Grota Vermelha on a pole, early rainy season.
    Cattle Herd
    Miguel Alves de Jesus crossing the swollen Grota Vermelha on a pole, early rainy season.

    Moving upslope from streams and adjacent flats, quartz gravel appears in patches at the surface of midslope sandy soils. Middle slopes are frequently marked by clay-brown lateritic concretions protruding through soil like angular boulders. Approaching slope tops, sands grade into finer-textured sandy clays, often with lateritic (dark brown) gravel mixed in. Where topographic relief is slight, gravelly sands may persist across the tops of slopes separating one drainage basin from another. No standing water or surface flow has been observed at high-ground positions, even during the heaviest rainstorms. Neither has extensive micro-topographic relief been seen on high ground.

    Fish-eye view of low-ground forest at Marajoara with clumping junçara (Precateria oleracea).
    Cattle Herd
    Fish-eye view of low-ground forest at Marajoara with clumping junçara (Precateria oleracea).

    The forest environment retains a humid interior through the first four to six weeks of the dry season beginning in early to late May, with morning dewfalls off of canopy crowns continuing well into June. Night-time temperatures fall as low as 15° C under clear skies. As the dry season progresses, high-ground understory environments dry out noticeably faster than low-ground areas adjacent to streams. After two months without rain, forest vegetation begins to demonstrate signs of moisture stress. Ambient humidity plummets, surface soils become dry to the touch, and forest green fades to paler, yellower hues as leaf litter on the ground builds beneath shedding trees. Daytime temperatures peak in August as the atmosphere thickens from a stagnant, humid haze compounded by smoke from fires set by surrounding smallholding farmers and ranchers on recently cleared forest plots and pastures. Nighttime temperatures rise as re-radiating energy is trapped by atmospheric particulates, and as the sun’s vertical position returns south from its solstice position in late June above the Tropic of Cancer. The wet season’s onset is fitful and its timing unpredictable from year to year. Localized thunderstorms fall in September during most years. These may be followed by weeks of renewed drought, as happened at Marajoara in 1995 and 1998; or rains may be delayed as late as November but continue unabated once begun, as in 1996; or rains may begin early and continue heavy, as in 2000. Once the rains have returned, the wettest months are January and March.

    The stilt-rooted palm at left, paxiba (Socratea exorrhiza), is restricted to low-ground forest at Marajoara.
    Cattle Herd
    The stilt-rooted palm at left, paxiba (Socratea exorrhiza), is restricted to low-ground forest at Marajoara.

    What are these forests like? First impressions are of an undifferentiated mass of tangled, impenetrable vegetation. Low and irregular overhead canopies mean that ground-level light levels tend to be high, fostering dense understory communities of small trees and shrubs, advance regeneration of overstory species, palms, herbaceous plants, and, where canopies are especially thin, grasses and sedges. Vines are ubiquitous, impeding passage and occasionally coalescing into draping thickets many hectares broad where overstory development is severely retarded. Tightly packed root-suckering groves of the banana-like sororoco (Phenakospermum guyannense, Strelitziaceae) appear frequently. Rarer, but occurring in larger patches, are thickets of a viciously hooked clumping bamboo. Small-statured mid-story tree species with deep, shade tolerant crowns dominate forest structure, topped by an overstory community that merges patchily and by occasional emergent trees like mahogany reaching 40 m in height. A remarkably high percentage of canopy species, mahogany included, are commonly classified as early successional or pioneer species in the literature and by field workers familiar with the regional flora. Tree- and branchfall gaps are frequent. The general feel of these forests is of a highly disturbed living environment for plants. Yet we have encountered no evidence of anthropogenic disturbance at Marajoara aside from logging.

    High-ground forest at Marajoara with dense vertical structure.
    Cattle Herd
    High-ground forest at Marajoara with dense vertical structure.

    Forest community patterns emerge with observation. The most important of these occurs across topographic and soil gradients as woody species sort into roughly dis-equivalent high- and low-ground communities. Mahogany’s apparent preference for low-ground topography anticipates this pattern: a group of dominant species (for being common, or for growing exceptionally large) show marked affinity for low ground or streamside positions. These include the clumping palm junçara (Euterpe oleracea, Arecaceae); the giant sumauma (Ceiba pentandra, Bombacaceae) and emergent axixá (Sterculia pruriens, Sterculiaceae); the large trees cinzeiro (Terminalia dichotoma, Combretaceae), maçaranduba (Pradosia sp., Sapotaceae), garra branca (Ampelocera edentula, Ulmaceae), and caximbeira (Cariniana domestica, Lecythidaceae); and the common midstory trees garra preta (Sloanea guianensis, Eleaocarpaceae), landí (Callophyllum brasiliensis, Guttiferae), and farinha seca (Licania sp., Chrysobalanaceae). The pasture-invasive emergent palm babaçu (Attalea speciosa, Arecaceae) is ubiquitous on low ground and may dominate local areas at densities many tens of large stems per hectare. In spite of the stature attained by many of these species, low-ground forests feel lower-canopied than high-ground communities, denser with vines and understory vegetation at walking level, more disturbed and brighter. Except where merging tall crowns thin groundstory vegetation by casting deep shade, the over-riding sensation from low-ground forest is of its chest-high density.

    High-ground forests appear taller, more vertically stratified, with more under- and midstory open space, shadier and cooler. A different set of species are dominant: the single-stemmed palm açaí (Euterpe precateria, Arecaceae); the giant cedrarana (Cedrelinga caetenaeformis, LegMimosoideae); the large trees mangue (Trattinickia burseraefolia, Burseraceae), mirindiba (Buchenavia capitata, Combretaceae), and angelim pedra (Hymenolobium heterocarpum, LegPapilionoideae); the tall, orange-stemmed angíco branco (Piptadenia sp., LegMimosoideae); overstory trees louro preto (Ocotea glomerata, Lauraceae), ingá branca (Inga alba, LegMimosoideae), pau d’agua (Tapirira guianensis, Anacardiaceae), and pará-pará (Jacaranda copaia, Bignoniaceae); the midstory cupania preta (Cupania scrobiculata, Sapindaceae) and Licania sp. (Chrysobalanaceae); and the arborescent palms paxiba (Socratea exorrhiza, Arecaceae) on tall stilt roots, and bacaba (Oenocarpus distichus, Arecaceae) whose crown grows on a single plane. Vines are common but rarely occur in spreading tangles. On average, it is easier to move about in these communities.

    Vine forest called cipoal at Marajoara.
    Cattle Herd
    Vine forest called cipoal at Marajoara.

    These distributional tendencies represent trends, not absolutes. Mahogany does occasionally occur on high ground, if rarely to the same stature it attains streamside; the high-ground tree mangue may be found streamside, though as a smaller version of its high-ground self. As well, a diverse community of species exhibit no apparent preference for topographic position or soil type, including the emergent trees jatobá (Hymenaea courbaril, LegCaesalpinioideae) and amarelão (Apuleia molaris, LegCaesalpinioideae), the spreading-crowned fava de bolota (Parkia pendula, LegMimosoideae), the overstory palm inajá (Attalea maripa, Arecaceae), midstory species like mangue amarelo (Thyrsodium sp., Anacardiaceae) and breu dente (Crepidospermum rhoifolium, Burseraceae), and the smaller but common under- and midstory tree called azeidinha (Rheedia gardneriana, Guttiferae).

    Within this larger forest matrix occur distinctive communities occupying areas hundreds of square meters to many hectares in extent. Where boulders or bedrock outcrop, on locally steep streamside slopes or across larger, flatter areas, associations of deciduous or semi-deciduous species gather, including candeia da mata (Colubrina sp., Rhamnaceae), Phyllanthus nobilis (Euphorbiaceae), peroqueiro (Myrcia sp., Myrtaceae), araçá (Eugenia sp., Myrtaceae), and, on boulders above streambeds, mahogany. Peroqueiro and araçá may form mono-dominant stands with widely spaced crowns that are nearly leafless during the dry season, in sharp contrast to surrounding evergreen forest. Vine forests on low ground are often characterized by a transitional cerradão tree called merím (Humiria balsamifera, Humiriaceae), and small-stemmed versions of characteristic low-ground species like caximbeira and landí. Low-ground forests occasionally grade abruptly into low-canopied shrubby cerradão communities, characterized by merím, kraíba (Tabebuia caraiba, Bignoniaceae), Curatella americana (Dilleniaceae), Bredemeyera sp. (Polygalaceae), ephiphytic orchids and Bromeliaceae, sedges, grasses, and the clumping palm buritirana (Mauritiella armata, Arecaceae). Elsewhere, otherwise undistinctive forest stands covering one to many hectares may be dominated by one or a handful of species, as, for example, quina (Aspidosperma auriculata, Apocynaceae) on midslope to high-ground sites, and babaçu or associations of garra preta and farinha seca on low-ground sandy soils.

    FOREST STRUCTURE & COMPOSITION

    Cattle Herd

    Differences in stem density and basal area between forests at high- and low-ground topographic positions at Marajoara among four paired 1-hectare inventory sites were consistent if not statistically significant. For stems > 30 cm diameter, high-ground forests had lower mean stem density but approximately equivalent basal area compared to low-ground forests, indicating larger mean stem size. For stems ≥ 10 cm diameter, at each site high-ground forests had lower stem density than low-ground forests due primarily to junçara palm clumps – multiple stems from common root stocks – that typically grow within five meters of stream banks. If root clumps were counted as single trees, relative stem density between topgraphic positions was reversed, to 567 ha-1 on high ground vs. 511 ha-1 on low ground. In spite of high low-ground stem density, basal area estimates were virtually identical, again indicating larger mean stem size at high-ground positions. For stems 2–10 cm diameter, high-ground forests had higher stem density. This was largely due to the single-stemmed palm açaí (Euterpe precateria), which occurred frequently in the understory at high-ground positions. At three of four paired sites, small-stem density was higher on high ground than on low ground, while per hectare basal area for this size class was higher at the high-ground position at all sites.

    Floristic identifications are derived from a reference collection of more than 450 species from Marajoara, collected from October 1995–November 2001 both randomly as new species and flowers were encountered, and systematically during forest inventories. The collection is housed at the IAN Herbarium at EMBRAPA/CPATU, Belém. Species collected through five years of fieldwork at Marajoara include:


    Species Genera Families
    trees, shrubs, strangling figs 335 222 65
    vines 76 59 26

    This list is comprehensive but not exhaustive; many more species, especially vines, remain to be collected and identified.

    Cattle Herd

    In the 4-hectare inventory among four paired high- and low-ground sites, 179 species ≥ 10 cm diameter were recorded. Of these, 49 species were represented by one individual, while 103 species were represented by fewer than 5 individuals. Among the 136 species recorded in nested plots (2–10 cm diameter, in 0.8 ha total), 36 were not included in the ≥ 10 cm sample, yielding a total of 214 species encountered during the inventory. (Vines were recorded but not identified; they are included in stem counts and basal area calculations but not in discussions of diversity.) Species area curves for trees ≥ 10 cm diameter show low-ground forests to be more diverse in 2 hectares of cumulative area, with 137 species vs. 110 species sampled in high-ground forests. From these data it can be estimated that 96 to 110 tree species ≥ 10 cm diameter occur in the average hectare covering both low- and high-ground positions in these forests (95% CI).

    Cattle Herd

    Importance values (IV), incorporating measures of frequency, dominance (through basal area), and distribution, have been widely used in species-rich tropical forests to rank species assemblages. To provide a forest-wide estimate of relative importance, we aggregated inventory data by slope position. For stems ≥ 10 cm diameter, only one species – Rheedia garneriana (azeidinha), a ubiquitous under- to midstory Guttiferae – was ranked in the top 10 at both slope positions. At each slope position, the 10 most important species included three which did not occur at the other position. That is, aside from azeidinha, ‘important’ species in low-ground forests were markedly less so in high-ground forests, and vice versa. This tendency was even stronger for stems ≥ 30 cm diameter, with only one species ranking in the top ten at both positions and each slope position including six or more species not occurring at the other position. Since these species tend to be rare, to some degree these data may reflect a sampling artifact.

    Because the observer’s impression of dominance and differentiation between slope positions derives largely from frequency of appearance by certain species, we pooled inventory data from 4 hectares to see whether the 10 most common species in successively smaller size groupings demonstrated marked ‘preference’ for high- or low-ground topographic positions. Species were designated as high- or low-ground specialists if > 80% of individuals occurred at one or the other position, and generalists if they were distributed 20–80% of the time between positions. Degree of site specialization was strongest by stems ≥ 30 cm diameter, with seven of 10 species occurring almost exclusively at one or the other position, and weakest by stems 2–10 cm diameter, with six of the most frequently recorded species designated as site generalists. Looking closely at the 2–10 cm group, it is noteworthy that seven of the 10 species are understory trees at maturity, implying that interior forest is occupied by a cadre of widely distributed shade tolerant species with abundant recruitment. At the visual level, as measured by occurrence frequency, forest communities sort by composition between slope positions.

    Cattle Herd

    Though low-ground forests had more species at three of four inventory sites, the Shannon diversity index assigned higher diversity values to high-ground forests in most cases. This was because the Shannon formula emphasizes evenness of distribution as well as species richness: as individuals are concentrated into fewer species, the index returns lower values. According to statistical t-tests, high-ground forests were more diverse (p > 0.001) at three of four site pairs, including the aggregated sample.

    The Morisita-Horn index compares forest composition between topographic positions by asking how quantitatively similar each is to the other. Comparisons were made at three levels: by adjacent site positions, for all combinations of equivalent site positions, and for data composited by position. The index returns a value between 0–1.0, with higher values representing greater similarity. With one exception, like position comparisons between sites showed greater similarity than high-ground/low-ground comparisons within sites. That is, low-ground pairs were generally more similar to each other than high-ground pairs. The aggregated comparison of high- vs. low-ground species, calculated from a dataset four times as large as other comparisons, showed the least similarity.

    SUMMARY

    Forest inventory data from Marajoara demonstrated community-level differentiation between low- and high-ground communities, reflecting mahogany’s own ‘preference’ for low-ground sites on or adjacent to streambanks. By importance value and by occurrence frequency it was possible to identify the principal constituents of distinctive communities that grade perceptibly one into the other moving up or down slopes. With reference to mahogany’s distribution pattern at Marajoara, similar maps or their mirror images could be drawn for many other species and for broadly defined communities as described here.

    Cattle Herd

    Hydrologic and edaphic gradients across slopes underlie these community patterns. High-ground communities may be characterized, on average, by deeply rooting species performing well in soils that are nutrient-poor compared to those at low-ground positions. Soil water relations at slope tops tend to be less extreme than those on low ground, but overall water is less available (horizons to 1 m retain more moisture through the dry season, but securely against plant uptake; the water table recedes deeper during the dry season). Even so, the deep-rooting habit in well-aerated soils leaves high-ground species less vulnerable to drought. Low-ground communities may be characterized by species tolerant of alternating swamp- and desert-like conditions as water tables perch and then plummet through wet and dry seasons. Anaerobic wet season soil conditions restrict rooting to sandy surface horizons that hold little water against gravity in the dry season, forcing pursuit of receding water tables by fine roots through dense gleyed subsurface soils. As occurred during the 1997–1998 El Niño, drought-induced mortality in low-ground communities can be high compared to high-ground communities. Though water relations are more extreme, surface horizons of low-ground soils are richer in macronutrients, especially Ca++, providing the boost for early growth that many species, including mahogany, may require for successful recruitment.

    The dichotomy thus appears to be, in simplest terms: high-ground species must be efficient water users capable of extracting water at great depth, and competitive in low-nutrient environments; low-ground species may be more profligate with water use but must also be capable of weathering occasional severe drought; they will tend to require richer soils for optimal early growth.

    The presence of cerradão species in forests at Marajoara, usually on low ground, often mixed in patches of low forests in pale or white sands on broad flats adjacent to streams, suggests that localized drainage characteristics may create extremely nutrient-poor soil conditions where drainage is impeded through the rainy season, either because of indurated sub-soil horizons or because relief is too slight to move water steadily out of the system.

    SPECIES DESCRIPTIONS

    Species are organized alphabetically by genus followed by family and local names (‘ ’). Links lead to a brief description of each species as observed at Marajoara. The following information is also provided: growth form, canopy position, (putative) regeneration habit, density, and (putative) dispersal agent(s).


    Growth form Canopy position Regeneration habit Density
    LT = large tree E = emergent LG = large gap F = frequent
    MT = medium tree OS = overstory SG = small gap C = common
    ST = small tree MS = midstory US = understory LC = locally common
    TL = treelet US = understory P = pioneer O = occasional
    CP = cipó (woody vine) R = rare

    SELECTED SOURCES

    Askew GP, Moffatt DJ, Montgomery RF & Searl PL (1971) Soils and soil moisture as factors influencing the distribution of the vegetation of the Serra do Roncador, Mato Grosso. In: Ferri MG (ed.), III Simpósio sôbre o Cerrado, pp. 150-160. Editôra de USP, São Paulo, SP, Brasil.

    Balée W & Campbell DG (1990) Evidence for the successional status of liana forest (Xingu River Basin, Amazonian Brazil). Biotropica 22: 36-47.

    Campbell DG, Daly DC, Prance GT & Maciel UN (1986) Quantitative ecological inventory of terra firme and várzea tropical forests on the Rio Xingu, Brazilian Amazon. Brittonia 38: 369-393.

    Cole MM (1960) Cerrado, caatinga and pantanal: distribution and origin of savanna vegetation of Brazil. Geography Journal 126: 168-179.

    Coutinho LM (1982) Ecological effects of fire in Brazilian cerrado. In: Huntley BJ & Walker BH (eds.), Ecology of Tropical Savannas, pp. 273-291. Springer-Verlag, Berlin, West Germany.

    Grogan, JE (2001) Bigleaf mahogany (Swietenia macrophylla King) in southeast Pará, Brazil: a life history study with management guidelines for sustained production from natural forests. PhD dissertation, Yale University School of Forestry & Environmental Studies, New Haven, CT, USA.

    Grogan J & Galvão J (2006) Physiographic and floristic gradients across topography in transitional seasonally dry evergreen forests of southeastern Amazonia, Brazil. Acta Amazonica 36: 483-496.

    Magurran AE (1988) Ecological Diversity and its Measurement. Princeton University Press, Princeton, NJ, USA.

    Ratter JA (1971) Some notes on two types of cerradão occurring in north eastern Mato Grosso. In: Ferri MG (ed.), III Simpósio Sôbre o Cerrado, pp 100-102. Editôra de USP, São Paulo, SP, Brasil.

    Ratter JA, Richards PW, Argent G & Gifford DR (1973) Observations on the vegetation of northeastern Mato Grosso. I. The woody vegetation types of the Yavantina-Cachimbo Expedition area. Philosophical Transactions of the Royal Society of London. B. Biological Sciences 266: 449-492.

    Ratter JA (1992) Transitions between cerrado and forest vegetation in Brazil. In: Furley PA, Proctor J & Ratter JA (eds.), Nature and Dynamics of Forest-Savanna Boundaries, pp. 417-429. Chapman & Hill, London, UK.

    Wolda H (1983) Diversity, diversity indices and tropical cockroaches. Oecologia 58: 290-298.

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