Modelagem da dinâmica do desmatamento de uma fronteira em expansão, Lábrea, Amazonas
Brazil’s “arc of deforestation” continues to expand across the Amazon region and has already reached the southeastern part of the state of Amazonas. A new focus of the deforestation has already affected a part of Lábrea, which is the municipality (county) that was recently found to have one of th...
| Autor principal: | Vitel, Claudia Suzanne Marie Nathalie |
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| Grau: | Dissertação |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
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| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/5151 http://lattes.cnpq.br/8667985096360144 |
| Resumo: |
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Brazil’s “arc of deforestation” continues to expand across the Amazon region and has already
reached the southeastern part of the state of Amazonas. A new focus of the deforestation has
already affected a part of Lábrea, which is the municipality (county) that was recently found
to have one of the highest deforestation rates in Amazonas. Pressure from the Arc originates
in the neighboring states of Acre and Rondônia, which already have intense deforestation
processes underway for the expansion and consolidation of the agricultural and ranching
frontier. In addition to the impacts caused to natural ecosystems in Lábrea, land-use changes
have induced a series of social conflicts through the process of “grilagem” (fraudulent
appropriation of large areas of public land) and from agricultural and ranching activities that
have contributed to the expulsion of extractive workers such as rubber tappers and Brazil nut
gatherers. Consequently, traditional families demanded the creation of extractive reserves to
protect themselves. In addition, as a part of the Program for the Acceleration of Growth
(PAC) the Ministry of Transportation plans to reconstruct the BR-319 (Porto Velho- Manaus)
Highway (which has been abandoned since 1988) and to recuperate a part of the marginally
passable Transamazon Higway (BR-230) that connects the BR-319 to Lábrea. To avoid the
environmental consequences of these projects, in 2006 the government proposed a series of
protected areas in the area of influence of the BR-319, four of which have been recently
created in the municipality of Lábrea. This study had the objective of modeling the future
spatial dynamics of deforestation in Lábrea and evaluating the usefulness of the recently
created protected areas in containing deforestation. Chapter I analyzes the effectiveness of
protected areas that have already been created in Acre, Rondônia and southern Amazonas.
The analyses revealed the usefulness of protected areas in containing deforestation: 90% of
the protected areas had deforestation rates inferior to those in a 10-km-wide strip surrounding
the protected areas. In addition, weights of evidence that represent the probabilities used in
the AGROECO model to simulate future deforestation inside the proposed areas have been
determined for the protected areas in this region, as well for the areas surrounding the
protected areas (10-km buffer). These weights of evidence have been determined specifically
for the category of use of each protected area and for the category of use in accord with its
administrative level (federal or state). Indigenous reserves were the most effective in repelling
deforestation, with a weight of -2.57; Integral Protected Areas were less efficient with a
weight of -1.23, and, finally, Sustainable Use Protected Areas were the most vulnerable with a
weight of -0.15. When considering weights of evidence as a function of the internal Euclidian
distance, weights declined when the internal distance was progressing from the edge of the
protected area to the center. Protected areas had weights of evidence that varied with the
internal Euclidian distance. These weights have been used in Chapter II, where eight scenarios
have been produced for the Lábrea region up to 2040 using the AGROECO model. Of the two
groups of scenarios, one didn’t consider the recent creation of protected areas (I), Business As
Usual while the other considered these areas, (II) Governance. In each scenario group, four
study cases have been considered including: 1- homogenously distributed weights of evidence
over the protected areas, 2- gradually distributed weights of evidence according to the internal
Euclidian distance, 3- homogenously distributed weights of evidence over the protected areas
and weights of evidence for the 10-km buffer areas, 4- gradually distributed weights of
evidence according to the internal Euclidian distance and weights of evidence for the 10-km
buffer areas. Creation of the protected areas has been little efficient because the majority of
the Governance group scenarios had slightly less deforested area in 2040 than did the
corresponding scenarios in the Business As Usual group. The use of gradually distributed
weights of evidence according to the internal Euclidian distance appears to be the most
realistic approach because it reduces the influence of deforestation occurrence in areas far
from the protected area limits. Considering the weights of evidence for the 10-km buffer area,
the surroundings of the protected areas have concentrated deforestation inside their limits
because their high weights of evidence make them more attractive to deforestation in the
simulations. However, this is believed to be a consequence of the years for which satellite data were available for calibrating the model, when the areas outside of the reserve buffers
had already been heavily deforested, leaving little left to clear. The most realistic scenarios for
our dataset are therefore considered to be those that use gradually distributed weights of
evidence but do not use separate weights for the buffer areas. In the scenario (GOV-2),
deforestation was reduced in the study area by 5,1 % (2.596 km 2 ) as a result of the creation of
the reserves, when compared to the corresponding baseline scenario (BAU-2). |