LC-05 Group Phase 2 Augmented Abstract

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

William F. Laurance, Smithsonian Tropical Research Institute (US-PI)
Rita Guimaraes Mesquita, BDFFP/INPA (SA-PI) 

Objectives

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.