Evolução do desmatamento em áreas protegidas sob influência da rodovia BR-319, na região de Vila Realidade, Humaitá, Amazonas

Abstract

Deforestation in the Amazon is caused by several activities, each with different degrees of impact. Among these activities are agriculture, cattle raising and urbanization. There is a strong correlation between the existence of official highways and deforestation and studies indicate that the reopening of the BR-319 highway linking Porto Velho and Manaus provides for irreversible impacts deforestation in protected areas caused by the occupation led by the highway is what this study is intended to quantify, as well as to analyze the occupation dynamics in the study area. This way the objective of this work was to analyze the evolution deforestation inside and outside protected areas motivated by the BR-319 occupation process in the Vila Realidade and adjacent areas, during periods before and after the announcement of rebuild the highway (2006). The study area is formed by a polygon whose central segment is a 100 km length stretch of the BR-319, starting from the junction with the BR-230 heading to Manaus, encompassing Vila Realidade and intersecting Balata-Tufari National Forest and Tapauá State Forest. Deforestation in the study area was calculated using PRODES data up to 2016; analyzes were performed encompassing a period preceeding the BR-319 rebuild announcement (2006) and a posterior period from 2006 to 2016, aiming to verify the evolution deforestation and the effect rebuild announcement on the area. To analyze protected areas inhibitory effect, a buffer ranging 10 km from the protected areas limits to the inside and the outside was stablished. As a result from the analyzes there was no significant increase in the acumulated deforestation in the year of the BR-319 rebuild announcement. However, starting in 2014, which was the year of the enviromental licensing emission for the maintenance/conservation of the highway, there was an increase of 2,212 hectares in 3 (three) year period, which means 43% of the deforestation occurred between 2001 and 2016. Accumulated deforestation polygons were mainly concentrated in and around Realidade. Spatial analysis exhibited that 88.7% of the accumulated deforestation until 2016 occured in a range of 5.5 km from official highways (BR-319 and BR-230) and/or 1.0 km from navigable rivers, 68.9% of which are related to deforestation in the BR-319 highway influence area. The deforestation outside the protected areas was higher than inside, this considering two 10 km buffers inside and outside their limits. In the Balata-Tufari National Forest the deforestation index ranged from 27.7 to 31.1 times more deforestation outside the protected area than in it's interior, in the Tapauá State Forest the deforestation index ranged from 11,4 to 12 times bigger outside the State Forest than in its interior. The spatial analysis demonstrated that the deforestation polygons found in the inner buffer ocurred by the Ipixuna river margins, while in the outter buffer the deforestation accumulated by the margins of BR-319 e BR-230 highways. Regarding the analysis of the land use and occupation dynamics in the study area, performed through TerraClass 2014 program data, the results showed that 48% of the areas are classified as Secondary Vegetation and 32.1% are classified as pasture. The roads are an inducer of deforestation and can be a great threat to the biodiversity of this region and protected areas play a relevant role as a conservation strategy.