Unidades de conservação e infraestruturas viárias: a percepção e o potencial dos efeitos marginais

Abstract

The transportation network is one anthropic component intensively present in the world and it can promote negative impacts on the environment. Those impacts have not only a direct effect, but can also extend beyond the road surface affecting the surrounding landscape. Conservation Units (CUs), a type of Brazilian legal protected area, are exposed to roads and influenced by them. The main objective of this research was to evaluate the potential effects of the road network in Conservation Units, aiming to characterize the perception of the employees regarding the negative impacts acting upon the CUs, to characterize the transportation infrastructure in them and to measure the area potentially impacted by road marginal effects. An online questionnaire, accessing the perception about presence and impacts of roads, was developed and sent by email to the CUs’ employees. Geospatial analysis was performed on GIS, by measuring road extension, density and the area potentially impacted by road effects in CUs. Road network characterization was compared by two approaches. The extension of road-effect zones acting on wildlife were obtained from a literature review. The found extensions were applied on seven scenarios to identify the area potentially impacted by road effects. The questionnaire was filled up by 278 employees of 290 CUs and geospatial analysis involved 1695 CUs. Both analysis found that the transportation network was present in the majority of CUs (69.3% by questionnaire; 59.3% by GIS), regardless of management category, administrative level, region or biome. Employees indicated road network as a promoter of both benefits and harms. They pointed out that road effects related to the abiotic environment tended to a slightly increase in the last five years. Furthermore, they also pointed out the decrease in animal abundance and illegal wildlife trade as critical effects. It was found about 124,000 km of road network inside CUs ( = 8.2 km) and a median density of 0.33 km/km². Extension and density values presented a wide variation. About half of the extensions reported by employees were not compatible with those found in GIS. The scenarios showed a range from 61.7 to 86.8% of CUs’ potentially affected, due influence of road marginal effects, that covers from 0.3 to 10.9% of Brazilian protected area. The seven scenarios presented CUs with area completely affected by road network effects. Conservation Units are facing an alarming situation due to transportation infrastructure presence since these areas, in all categories, contain roads or are suffering with their marginal effects. The objectives of each category of CU should be considered and roads should be maintained where they are compatible, properly monitored and managed. Optimization and planning of the road network are the keys to the sustainability of this sector.