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S.R. Freitas et al. 2010. The effect of highways on native vegetation and reserve distribution in the State of São Paulo
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Clevenger 2005; Palomino and Carrascal 2007; Fahrig and Rytwinski 2009; Laurance et al.
2009).
Understanding the relationship between highways and native vegetation would improve
methods to select priority areas for conservation and restoration and the effectivity of those new
wildlife nature reserves. This work aims to: 1) estimate areas which have been ecologically
affected by highways, in the whole state of São Paulo, for each type of vegetation, and in all
nature reserves; and, 2) investigate the influence of highway distance on the native vegetation
cover and on the reserve distribution.
2. Methodology
The study area was the State of São Paulo, in the southeastern of Brazil. In that State, there are
two biomes considered as biodiversity hotspots for conservation: Atlantic Forest and Cerrado
(Myers et al. 2000).
We used the state’s road map, produced by DER (2008) and classified by road types: nonpaved
roads, paved roads with two lanes, highways (paved roads with four lanes) and
expressways (paved roads with at least four lanes and high traffic). We also used a native
vegetation map with the following vegetation types: Savanna and Semideciduous Seasonal
Forest (both from Cerrado biome), and Serra do Mar Coastal Forests, Araucaria Moist Forests,
Mangroves and Atlantic Coast Restingas (from Atlantic Forest biome).
We included only the nature reserves classified as Full Protection in the Brazilian
Environmental Legislation (SNUC) performing 62 nature reserves in the State of São Paulo.
We estimated the areas which have been ecologically affected by roads in the whole State of
São Paulo, in each type of vegetation and in the nature reserves following the methodology
used by Forman (2000). The area ecologically affected by roads was evaluate using the
distance where the sensible bird species are affected because they are negativelly affected by
roads (Reijnen et al. 1995, Forman 2000, Develey e Stouffer 2001). Roads with high traffic
flow were considered those with the higher ecological effect, thus the buffer width varied to
road type (Forman 2000, Liu et al. 2008): non-paved roads have 200 m buffer width, paved
roads 365 m, highways 810 m and expressways 1000 m.
The relationship between native vegetation and road distance was evaluated using 10 noninclusive
buffers: 0-50 m, 50-100 m, 100-250 m, 250-500 m, 500-750 m, 750-1000 m, 1000-
1250 m, 1250-1500 m, 1500-1750 m, 1750-2000 m. In each buffer, we measured the total area
of native vegetation.
3. Result
Road density in the São Paulo State was 0.145 km/km 2 . Paved roads were the most abundant
(0.070 km/km 2 ), followed by non-paved roads (0.060 km/km 2 ), highways (0.010 km/km 2 ) and
expressways (0.006 km/km 2 ).
More than 2,375,600 ha (10%) of the territory was affected ecologically by roads. The State of
São Paulo was most affected by paved roads (4.7%), followed by non-paved roads (2.2%),
highways (1.5%) and expressways (1.2%).
About 5.4% of the native vegetation cover were affected by roads. The Atlantic Forest biome
has about 5.3% of its cover affected by roads, whereas 5.9% of the Cerrado biome were affected
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.