Ra. Washingtonallen et al., CHANGE DETECTION OF THE EFFECT OF SEVERE DROUGHT ON SUBSISTENCE AGROPASTORAL COMMUNITIES ON THE BOLIVIAN ALTIPLANO, International journal of remote sensing, 19(7), 1998, pp. 1319-1333
The purpose of this study was to identify the ecological effects of dr
ought on the vegetation resources of subsistence agropastoral communit
ies on the Bolivian Altiplano. The objectives of the study were to (1)
characterize vegetation cover response during a typical year, and (2)
identify vegetation cover type's response to drought using an image d
ifferencing change detection technique. A geographical information sys
tem (GIS), which included multi-temporal (from 1972-1987) Landsat sate
llite imagery, was used as the assessment tool. Vegetation index diffe
rence images showed that (1) all vegetation types were impacted by dro
ught, but the wet meadow vegetation cover type had the least response,
and (2) approximately 90 per cent of vegetation cover had not changed
between 1972 and 1987. Crop and animal production in agropastoral sys
tems are dependant on the availability of vegetation resources. The we
t meadow vegetation type was the most resistant to drought, which sugg
ests that during drought periods it is a key resource upon which the l
ivestock of the community would depend. Little change in vegetation co
ver over the 15-year span of the study, and the rapid recovery of this
parameter following the drought of 1983-84, suggest that agricultural
practices (especially livestock grazing) are not contributing to reso
urce degradation when measured only in terms of change in vegetation c
over.