This report is a contribution to the discussion on ecological adaptation of the road infrastructure and a stage in the Environmental Impact Assessment (EIA) for a new section (Bogla-OEggestorp, 5 km) of Highway 31 to the south east of Joenkoeping in the south of Sweden. The aim is to illustrate the handling of ecological issues in the EIA and to give a preliminary estimate, for both the tunnel and non-tunnel alternatives, of the ecological impact of the road at the fault scarp near the village of Bogla. The work is based on existing preliminary EIA reports, general ecological knowledge and international measures for ecological adaptation of the infrastructure. Emissions of HC, CO, NOx and CO2 with and without a tunnel were simulated for 1993 and 2004. The natural values in an area should be assessed using various scales of space and time. On the small spatial scale, natural values which are destroyed by the road, and disturbance to plants and animals in the vicinity of the road, are identified. On the larger scale, an assessment is made of the influence of the road on the migration of animals and the exchange of individuals and genes in and between populations. Assessment of the value of nature in the area should be based not only on individual species and habitats but also on the large scale features of the area as a whole. It should be borne in mind that natural values may increase over time and that the value which society places on nature is subject to constant change. In the absence of a developed methodology for pricing, it is impossible to put a monetary value on the natural value of areas. In the study area, the botanical, zoological and geological values, combined with the small scale topography, form an entity that is of great value for nature conservation. The continuity in time and space of the natural environment of the fault scarp and Klevaberg forest should be given special consideration. A road would weaken the landscape-ecological connections, contribute to the fragmentation of the landscape and habitats, and would in the long term threaten rare mosses and lichens. The barrier effect of the road would be limited if the tunnel alternative were chosen, an animal underpass constructed, provision for wildlife made in the planned underbridges, and the bridge over Femtingaaa brook adapted to the migration of terrestrial and aquatic animals. According to the simulation, there is no difference in exhaust emissions between the tunnel and non-tunnel alternatives. Steps should be taken to prevent runoff from the road reaching watercourses and wetlands untreated. The situation prior to the project should be documented to serve as the basis for the post-project analysis. (A) (The Swedish version of this report is VTI Meddelande 792).
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