Characterizing patterns of agricultural land
use in Amazonia by merging satellite imagery and census data.
Jeffrey Alan Cardille - 2002
[UMI Proquest
Full
Citation]
In recent decades, millions of hectares of Amazonian
primary forest, cerrado, and secondary forest have been cleared to support
a dramatically increasing number of cattle and humans. With plans proposed
for major new highways and utilities in the basin, development is highly
likely to continue in coming years. Conversion to human use threatens to
change the climate, ecosystems, and natural resources of Amazonia, and these
effects are due not only to changes in land cover but to the land use management
practices that follow. Unfortunately, we lack basin-wide information about
land use across Amazonia. A key reason for this dearth of information is
that earth-observing satellites designed to interpret land cover are prone
to miss the land use changes within; in an area encompassing millions of
square kilometers, it is impossible to visit more than a small portion of
the study region to quantify land use activities. Agricultural censuses suggest
a strategy to fill this gap: in Amazonia, they provide the only ground-surveyed
land use information — yet because they are not easily reconciled with
satellite-based land cover information, census data are underutilized. The
research forming this dissertation presents a new, basin-wide depiction of
land use in Amazonia by developing and applying new tools for understanding
the past, current, and future impact of agricultural development. Specifically,
this dissertation: (1) presents a new detailed understanding of the
distribution and density of agricultural land use practices in Amazonia in
the mid-1990s by fusing agricultural census data with satellite-derived land
cover classifications; (2) assesses historical changes in agriculture
of the previous decades; and (3) describes and applies new general techniques
for the rapid update of land use data sets and maps using satellite imagery
and census data. The fusion of census and satellite data described here advances
our understanding by uniting the strengths of two distinct types of information
about human activity in Amazonia. The contributions presented here provide
demographic, economic, and ecological studies with new knowledge of the location,
density, and history of crucial agricultural land use processes in this highly
threatened and rapidly changing region.