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LC-05 Abstract

Anthropogenic Land-use Change and the Dynamics of Amazon Forest Biomass

William F. Laurance — James Cook University (US-PI)
Rita Guimaraes Mesquita — Instituto Nacional de Pesquisas da Amazonia -INPA (SA-PI)

This investigation seeks to understand the impacts of

prevalent land-use changes such as habitat fragmentation and forest regeneration

on the dynamics of biomass and carbon storage in Brazilian Amazonia. 

Further goals include assessing the effects of anthropogenic climate change and

El Niño-related droughts on fragmented and intact forests.  This project

is also playing a vital role in providing advanced training for Amazonian

graduate and undergraduate students, postdoctoral researchers, and government

decision-makers.



A key strategy of this investigation is to extrapolate

upward from intensive studies at local and landscape scales to much larger

regional and basin-wide scales.  This is accomplished by various modeling

approaches that link long-term studies of forest dynamics and biomass in

fragmented and regenerating forests in central Amazonia with remote-sensing

data, including Landsat TM and AVHRR at regional scales, and higher-resolution

techniques at landscape and local scales.



This study incorporates one of the world’s most

important datasets on tropical forest dynamics.  Within the 1000-km2 study

area of the Biological Dynamics of Forest Fragments Project (BDFFP) near Manaus,

a long-term (>23 year) investigation of forest biomass, carbon-cycle

dynamics, and plant diversity and community composition is being conducted using

69 1-ha plots in fragmented and intact forests.  Within these plots,

>60,000 large (>10 cm diameter) trees of ca. 1,200 species have been

continuously monitored since 1980.  In addition, virtually all other

components of aboveground biomass (small trees, saplings, seedlings, palms,

lianas, snags, fine and coarse wood debris, litter standing stock) are being

quantified, providing insights of unparalleled detail into the striking

ecological impacts of forest fragmentation on carbon storage and cycling and

plant-community dynamics.



In addition, long-term biomass studies are being

undertaken to help determine whether intact Amazonian forests are functioning as

a significant carbon sink (possibly in response to increasing CO2

fertilization).  Carefully selected plot chronosequences are being used to

study the dynamics of carbon sequestration and floristic change in forests

regenerating on abandoned lands, and are revealing the critical role of

disturbance history in forest regeneration. 

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