02579naa a2200409 a 450000100080000000500110000800800410001902400380006010000170009824501240011526000090023952013770024865000150162565000160164065300190165665300250167565300340170065300300173465300370176465300190180165300220182065300250184270000150186770000180188270000190190070000200191970000170193970000190195670000190197570000230199470000150201770000210203270000210205370000160207470000210209077300580211119644312013-08-21       2013    bl uuuu     u00u1 u    #d7 a10.1080/17550874.2013.7836422DOI1 aSCHIETTI, J.  aVertical distance from drainage drives floristic composition changes in an Amazonian rainforest.h[electronic resource]  c2013  aBackground: Plant composition changes with topography and edaphic gradients that correlate with soil-water and nutrient availability. Data on soil water for the Amazon Basin are scarce, limiting the possibility of distinguishing between soil and soil-water influences on plant composition. Aim: We tested a new proxy for water table depth, the terrain height above nearest drainage (HAND), as a predictor of composition in trees, lianas, palms, shrubs, and herbs and compared HAND to conventional measures of height above sea level (HASL) and horizontal distances from nearest drainage (HDND). Methods: Plant-species composition in 72 plots distributed across 64 km2 of lowland evergreen terra firme forest was summarised using non-metric multidimensional scaling (NMDS). NMDS scores were regressed against estimates of HAND, HASL and HDND. Results: Plant composition was highly correlated with the vertical distance from water table, capturing up to 82% of variation. All life forms showed highest turnover rates in the zone with seasonally water-saturated soils, which can extend 350 m from stream margins. Conclusions: Floristic composition is closely related to water table depth, and HAND appears to be the most robust available topographical metric of soil-water gradients. Brazilian conservation laws protecting 30-m-wide riparian buffers are likely to be too narro  aTopography  aWater table  aBeta diversity  aDistance from stream  aHeight above nearest drainage  aPlant species composition  aShuttle Radar Topography Mission  aSoil hydrology  aTerra fime forest  aTropical rain forest1 aEMILIO, T.1 aRENNÓ, C. D.1 aDRUCKER, D. P.1 aCOSTA, F. R. C.1 aNOGUEIRA, A.1 aBACCARO, F. B.1 aFIGUEIREDO, F.1 aCASTILHO, C. V. de1 aKINUPP, V.1 aGUILLAUMET, J-L.1 aGARCIA, A. R. M.1 aLIMA, A. P.1 aMAGNUSSON, W. E.  tPlant Ecology & Diversitygv. 8, n. 5, p. 1-13, 2013.