A large number of newly published and unpublished hectare plots in Amazonia and the Guiana Shield area allow an analysis of family composition and testing of hypotheses concerning alpha-diversity in the south American rain forest. Using data from 94 plots the family-level floristic patterns in wet tropical South America are described. To test diversity patterns, 268 plots are used in this large area. Contrary to a widely held belief, western Amazonian plots are not necessarily the most diverse. Several central Amazonian plots have equal or even higher tree diversity. Annual rainfall is not a good estimator for tree diversity in the Amazonia area and Guiana shield. Plots in the Guiana Shield area (and eastern Amazonia) usually have lower diversity than those in central or western Amazonia. It is argued that this is not because of low rainfall or low nutrient status of the soil but because of the small area of the relatively isolated rain forest area in eastern Amazonia and the Guiana Shield. The low diversity on nutrient-poor white sand soils in the Amazon basin is not necessarily due to their low nutrient status but is, at least partly, caused by their small extent and fragmented nature.

As part of an integrated forest vegetation and soil survey, tree species composition (DBH > 10 cm) was recorded in 95 plots of 0.1 ha, distributed over the principal physiographic units in the middle Caquet~i area, Colombian Amazonia. A total of 1077 tree species was found, classified into 271 genera and 60 families. Leguminosae and Sapotaceae show high familial importance values in all physiographic units. Lauraceae, Chrysobalanaceae, Moraceae, and Lecythidaceae are more important on well drained (flood plain or upland) soils, while Palmae, Guttiferae, Bombacaceae, and Apocynaceae are more important in swamps and on podzolised ('white sand') soils. Plots on well drained soils show a lower degree of dominance than plots in swamps or on podzolised ('white sand') soils. The composition of the most dominant slSecies in the plots changes continuously. Most species (59%) are only recorded in one plot. Individual plot pairs generally show a low overlap of about 2-5 tree species, resulting in Jaccard coefficients below 20%.Complementary to a previous forest classification based on TWINSPAN analyses, detrended and canonical correspondence analyses were carried out, using CANOCO 3.1. Despite of a low amount of tree species variance explained (only 6.2% by the first two canonical axes), meaningful patterns of tree species composition were recognised. These are most strongly related to drainage, flooding, humus forms, and soil nutrient status. Forest types are well separated in the CCA ordination diagram. The most frequently found tree species are listed according to their preference with respect to drainage, flooding, and soil nutrient status.Tree species composition in the well drained upland forests was analysed separately. In view of the model explaining high NW Amazonian tree species diversity on the basis of dense community packing and high beta diversity along soil gradients, the canonical analysis here focused on the effect of soils. By means of partial canonical ordination it was found that patterns of tree species composition depended significantly on soil properties, even though the edaphic component explains only a small fraction of the tree species variance. The results show that the well drained uplands of the middle Caque~ area are covered by a complex of two intergrading tree species assemblages. The first assemblage (community of Goupia glabra-Clathrotropis macrocarpa) is associated to somewhat less poor, clayey soils developed in Andean origin deposits or Tertiary sediments from the Pebas formation. The second assemblage (community of Swartzia schomburgkii-Clathrotropis macrocarpa) shows affinities to very poor, loamy soils developed in parent materials derived from the Guiana shield. This simple dichotomous pattern of geology, soils, and forest types is incompatible with concepts of high soil heterogeneity and associated beta diversity controlling tree species diversity in well drained uplands of NW Amazonia. The gradient length of tree species in the detrended Correspondence analysis was low (3.7 SD), al...

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RESUMENCon base en información obtenida sobre los nombres de todas las plantas con DAP > 2.5 cm (Diámetro a la Altura del Pecho, medido a una altura de 1.3 m) dentro de 30 parcelas de 0.1 ha cada una, y sobre los suelos, la vegetación y el paisaje a lo largo de 8 transectos (entre 2 y 5 km de longitud cada uno), se describen los aspectos más importantes sobre la taxonomía botánica y el ordenamiento o jerarquización del medio ambiente desde la perspectiva de los Indígenas Miraña de la Amazonía central colombiana. A pesar de la pérdida cultural, algunos pocos ancianos guardan como parte de su tradición oral, los elementos básicos de un sistema complejo de conocimiento de su ambiente natural. Se detectó un alto grado de conocimiento sobre las especies vegetales silvestres, la existencia de sistemas nomenclaturales para éstas y para los suelos, y un reconocimiento organizado de paisajes fisiográficos y tipos de vegetación. PALABRAS-CLAVE:Miraña, Sistemas tradicionales de clasificación, Etnotaxonomía, Etnoecología, Ecología del paisaje. Plants, soils and landscapes: sorting of nature by the Miraña Indians of Colombian Amazon. ABSTRACTWe describe the most important aspects of Miraña's plant taxonomy, and landscape categorization. Data about plants' names (in 30 plots of 0.1 ha), was gathered from all individual plants with DBH > 2.5 cm (Diameter at Breast High, or 1.3 m above ground), and data about soils, forest types and landscapes was gathered from 8 transects of 2-5 km long each. In spite of cultural lost, complex knowledge about natural environment classification, it is present into the oral tradition keep in some elders' mind. We detected a high level of knowledge about wild plants, the presence of nomenclatural systems for plants and soil types, and organized landscapes and forest types systems.