A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

Ecological Classification of Soils and Pristine PremontaneVegetation in the Alto Mayo Valley, Northern PeruViviana Horna 1,2) , Johannes Dietz 1) , Tobias Mette 1) , Annett Börner 1,2) ,Jan Dempewolf 1,3) , Reiner Zimmermann 1,2)1Forest Ecology and Remote Sensing Group, Ecological-Botanical Gardens ÖBG, Universityof Bayreuth, 95440 Bayreuth, Germany2Max-Planck-Institute for Biogeochemistry MPI-BGC, Jena, Germany3University of Maryland, U.S.A.viviana.horna@bgc-jena.mpg.de Phone: ++49-3641-686731 Fax: ++49-3641-686710AbstractAn ecological classification method for pristine vegetation at the eastern slopes of the North Peruvian Andeshas been developed. Emphasis was on forest structure, biomass and soil properties and interrelations with thetopographic and geologic situation.Forest plots for intensive structural measurements and soil description (currently > 200) were taken alongtransects and typical catenae in the Río Avisado and upper Río Tioyacu watersheds. Study plots reach from800 m to > 1600 m a.s.l. and cover different topographic and geologic situations. The stand structural,topographic, and soil parameters which were obtained in the field were analyzed by principal component andhierarchical cluster analysis. The vegetation types were characterized by topographic position, soil organiclayers, mineral soil, tree size, stand density, life forms, canopy density as well as dead and living biomass. Wateruse by contrasting vegetation types was analyzed using site climate data and tree sap flow measurements.The classification resulted in a statistically significant separation of major vegetation types:(a) Palm forests (Aguajales), (b) Ficus ssp. swamps (Renacales) and (c) alluvial plain forest inseasonally inundated areas of the lower watersheds, (d) Valley forest, (e) hill forest, (f)montane rain forest, and (g) three types of heath forest (Chamizales) in the upper parts of thewatersheds. All vegetation types showed significant differences in soil and plant nutrientstatus, growth patterns, and/or in site climate. Stand structural properties were used forsubsequent biomass calculation of all vegetation types. Biomass ranged from 14 ± 6 tons perhectare in open heath forests to 245 ± 147 t ha -1 in montane rain forests.By overlaying stereoscopic aerial photographs, satellite imagery, a digital elevation model and geologicinformation using a geographic information system, a reliable forest type map for the study area was obtained.The classification of the present vegetation of both watersheds provides the basis for an ecological sensitivityanalysis of forests and soils and the development and implementation of an environmental monitoring system atthe Margen Izquierda (Bosque de Protección) of the Alto Mayo Region.