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ND-01 Abstract

Land Cover Conversion in Amazonia, the Role of Environment and Substrate Composition in Modifying Soil Nutrient Cycling and Forest Regeneration

Paulo Gonçalves Barreto — Imazon (SA-PI)
Dar A. Roberts — University of California (US-PI)
Joao Vianei Soares — INPE - Instituto Nacional de Pesquisas Espaciais (SA-PI)

We propose an integrated remote sensing and

field-based examination of the causes and biogeochemical consequences of

regional land-cover change within the Arc of Deforestation in the southern

Amazon Basin. Research components include field observations, regional

synthesis, and multiresolution studies, with a major focus on remote sensing. 

We will refine the standardized methods we developed during LBA-ECO Phase I for

consistent mapping of regional land-cover conversion through time. The

techniques will be expanded to include diverse environmental variation, and new

methods will be developed to map forest degraded by logging, fire, and

fragmentation.  These remote sensing products will be combined with

ancillary data sets and field measurements to evaluate the relative importance

of environmental and human controls on patterns of land-cover change, and the

consequences of land-cover change for vegetation growth and succession and for

soil and stream biogeochemistry.  Our previous research in Rondônia shows

that variations in topography and rock type generate significant gradients in

natural soil fertility and stream nutrient concentrations across the state. 

Roads and urban networks, superimposed on this natural variation, constrain or

accelerate land-cover conversion and have important consequences for human

impacts on stream biogeochemistry.

Our questions represent diverse

academic disciplines, but all aim to combine remote sensing with field

measurements to develop an integrated understanding of regional patterns in

land-cover change and its biogeochemical consequences.  In addition to

producing a variety of remote sensing products to monitor land-cover change, we

will address the following questions:  How can remote sensing methods be

combined with field measurements to better quantify changes in vegetation

community structure due to selective logging, and how extensive are those

changes?  What are the topographic and geologic determinants of soil

mineralogy and fertility across the state of Rondônia, and how does this

natural variation in soil type constrain or promote land-cover conversion? 

Finally, how do vegetation conversion and the evolving human settlement system

affect terrestrial and aquatic biogeochemistry and over what scales do these

drivers operate?

Our research approach can be

divided into three intersecting phases: 1) mapping and monitoring a suite of

land-cover changes; 2) evaluation of the natural and human drivers of forest

conversion; and 3) measurement of the impacts of those changes on forest

structure in selectively logged areas and on soil and stream biogeochemistry in

areas converted to pasture.  The research will be conducted in the

Brazilian states of Rondônia and Mato Grosso, which show significant intra- and

interstate variations in deforestation rates, selective logging intensity, urban

development, and environmental gradients.  An important aspect of the

project is a dedication to exchange research methods and techniques in the LBA/Amazon

research community, most intensively among Imazon, INPE, and UCSB. 

Institutional exchanges will provide an opportunity for intensive training, data

sharing and research collaboration among U.S. and Brazilian participants.

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