Geoscience Reference
In-Depth Information
Study weaknesses included the intrinsic limitations imposed by the use of the different satellite
sensors (i.e., MSS, TM, and ETM
). Also, reference data sizes for some cover classes were relatively
small and interviewees expressed greater levels of uncertainty in retrospective data reconstruction
than for the current time period. Despite these constraints in data collection, we were confident
that they did not represent an extra burden compared to the challenge of obtaining good levels of
agreement among remote sensing specialists when using other techniques such as high-resolution
videography. The application of an integrated field data collection process would have enhanced
the quality of our data. Such an integrated process would comprise simultaneous collection of
remotely sensed ground data and household socioeconomic surveys on LU/LC to facilitate direct
comparison between data sources.
The level of detail of our classification scheme was similar to that used by other investigators
in the region, and our map accuracies compared favorably with their results (Rignot et al., 1997;
de Moraes et al., 1998). For local stakeholders, however, our classification scheme was not suffi-
ciently detailed. Stakeholders would most like to clearly distinguish specialty crops such as cacao,
coffee, and shade coffee, which would not be practical with the resolution of these data sets.
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6.5 SUMMARY
This study assessed LC change in a recent colonization area in the municipalities of Machadinho
D'Oeste and Vale do Anari, State of Rondonia, Brazil. Landsat MSS, TM, and ETM
data were
used to create maps of LC conditions for 1986, 1994, and 1999. Images were obtained in July/August
(dry season) and field data were collected during August 2000 with the assistance of nine local farm
associations and approximately 100 independent farmers. At meetings with the associations, hard
copy false-color composites of imagery data with parcel boundaries were presented to individual
landowners. Each individual provided historical and contemporary LU for known areas. Polygons
were annotated and labeled on stable acetate for each cover type, corresponding to the seven-category
classification scheme. Notes were taken during the interview process to indicate the dates of land
clearing, cover type, and level of uncertainty expressed by the participants.
Approximately 1000 polygons were field-annotated and random samples were selected for
classifier training and map validation. Spectral signature files were generated from training polygons
and used in a supervised classification using maximum likelihood classification. Overall accuracy
for each year ranged between 85 and 95% (Kappa 0.52-0.78). LC changes were consistent with
the trends observed in the study area and reported by others. The participatory process involving
local farmers was crucial for achieving the objectives of the study. The specific protocol developed
for data collection should be applicable in a wide range of cases and contexts.
The building of trust with the local stakeholders is important with contested issues such as
deforestation in the tropics. Systematic data collection among farmers (the primary land users)
provided a valuable source of information based on their direct observation in the field and historical
data not directly available through other sources. This procedure provided greater confidence for
interpreting and understanding classification errors. Finally, the process itself empowered local
farmers and provided a forum for discussing land use processes in the region, including challenges
to alleviate poverty, increase agrosilvopastoral farming systems, arrest deforestation, and study its
implications for developing more effective land use policies.
Including the local stakeholders in the research was a very effective process for evaluating LC
change in the region. For stakeholders and researchers, the mapping and reporting process fosters
better understanding of the patterns and processes of environmental change in the study area. We
foresee that participatory mapping projects such as the one reported in this chapter have the potential
to become an important planning device for regional-scale development in Brazil. With greater
economic opportunities and stronger institutions at the local level, society is likely to improve the
ability to identify and adopt more environmentally sound LU activities.
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