The Cultivation and Use of Taro and Fruit Pandanus among he Duna of the Aluni Valley of the Southern Highlands of Paua New Guinea

Any scholar interested in the plants or practices associated with vegeculture, past or present, will value the contributions in this volume. It speaks to agricultural issues relevant far beyond the geographic focus indicated by the title, and it addresses a wide variety of taxa from the perspectives of plant physiology, molecular biology, ethnography, archaeology, and agricultural development. Moreover, Japanese scholarship is highlighted, providing an excellent forum for those contributors whose research is not widely disseminated in English. This volume results from a symposium held Nov. 06–09, 2000 at the National Museum of Ethnology, Osaka

Ecological gradients within the riparian forests of the lower Caura River, Venezuela

The distribution of woody species within the 260 km-long riparian corridor of the Lower Caura River, a nutrient-poor tributary of the Orinoco River, draining the Guiana Shield in Venezuela is related to environmental variables. TWINSPAN clustering and a Canonical Correspondence ordination were used on abundance data for the 110 most common tree species in 51 sample plots. Four groups are identified: (i) upstream of La Mura Rapids, narrow floodplains in constrained valleys with steep slopes show marked differences between sites dominated by channel lateral accretion (levees, Group B) and overbank deposition (swamps, Group A), (ii) downstream of the rapids, levees (Group C) are differentiated from a more heterogeneous floodplain (Group D) influenced by a backwater effect caused by the ponding of the Caura River by the Orinoco. A Multiple discriminant analysis of these groups resulted in a function including depth of inundation, ratio of alkaline/alkaline earth major cations, and soil phosphorous content, which accounted for 83% of the variance between the four groups. Inundation level and phosphorous content were also the most significant variables in the ordination, within which the first two axes explained 48% of the species- environment relationships. Tree density, species richness and diversity (H') are shown to change significantly along the lower Caura with highest values associated with levees in sectors upstream of the La Mura Rapids; effects of terrestrialization and intermediate disturbance are proposed to explain these patterns. Floristic elements typical of both Amazonian Igapó and Várzea forests are shown to occur along the whole riparian corridor of the lower Caura, but the majority occur downstream of La Mura Rapids. The intermediate nutritional status of the Caura River and a hydroecological confluence effect associated with higher flooding depths and stronger biogeochemical gradients along the lower reach are suggested to explain the co-occurrence of Igapó and Várzea species

Ecohydrology of riparian forests in the Orinoco River Basin

This paper describes some important ecohydrological interactions within riparian forests in lower Orinoco using the Caura and Mapire rivers in Venezuela. The importance of riparian forests and hydrological seasonality for aquatic faunal ecology and human use patterns are examined using the Caura River. On the other hand, the influence of ecohydrology on the composition, structure and diversity of riparian forests communities was analysed using the Mapire River. By comparing the decomposition processes of the Caura and Mapire floodplains, ecohydrological interactions of biochemical gradients along river confluence zones are discussed

Elliptic Fourier Analysis of leaf outlines in five species of Heteropsis (Araceae) from the Reserva Florestal Adolpho Ducke, Manaus, Amazonas, Brazil

Summary: A pilot study of leaf outline morphometrics was carried out on populations of five species of Heteropsis located in the Reserva Florestal Adolpho Ducke near Manaus, Amazonas, Brazil: H. flexuosa (Kunth) G. S. Bunting, H. macrophylla A. C. Sm., H. spruceana Schott, H. steyermarkii G. S. Bunting and H. tenuispadix G. S. Bunting. The aim of the study was to investigate quantitative methods for discriminating species within a local area based on vegetative morphology in a genus where fertile parts are often difficult to find in the field; this study focussed on leaf outline shape. Using digital images of 347 leaves, outlines were captured as coordinates using the TpsDig software and analysed using Elliptic Fourier Analysis (EFA). Principal Component Analysis (PCA) was used to reduce the 160 elliptic Fourier coefficient descriptors to a smaller number of independent shape variables corresponding to the principal component axes. The first nineteen shape variables (constrained by the smallest species sample, N = 20) were then subjected to Linear Discriminant Analysis (LDA) to find new axes that would discriminate the five species to the maximum extent. The first six shape variables were visualised by a reification procedure in order to illustrate their characteristic contribution to the total shape variation within all five species. The results showed that the mean shapes of all five species were significantly different, but shape variation within each species overlapped with the others. Percentage assignment of individuals to their correct species was encouragingly high given that only outline shape was used, but was not high enough overall to provide reliable identification. Elimination of one species (H. steyermarkii) using easily observed qualitative vegetative characters improved discrimination of the remaining four. The investigation of new approaches to identification is potentially valuable for conservation of natural populations - the root fibre of Heteropsis is extracted from primary forest and is a valuable non-timber forest product that forms the basis for an important local industry in Amazonia. © 2011 The Board of Trustees of the Royal Botanic Gardens, Kew