The relevant causal chains between the traffic and the nature and the landscape have been identified in the preliminary study I. The preliminary study II investigated whether it is possible to determine the mixed structure of the external nature and landscape effects by comparison of the aerial photographs from the '50s with the aerial photographs from the 90s. This pre-test defined the exact scope, the methodology and the approach for main study.
The analysis of the aerial photographs will produce a quantitative respectively monetary information on habitat, habitat quality and loss of habitat fragmentation since the 50s. The results will be representative of the whole of Switzerland. The resulting costs have to be divided between the two modes of transport road / rail and within this on the passenger and freight transport. Alternative assessment procedures and possible internalisation shall be identified, if necessary.
This pre-test defined the exact scope, the methodology and the approach for main study findings. There is still a degree of uncertainty by the particular number of evaluated aerial images. The project will evaluate 300 of aerial images.
The determination of the external costs of transport on nature and landscape is based on a range of preliminary work in which such external costs were identified and the methods for their monetarisation evaluated (Ökoskop 1998). The following relevant impacts of transport on nature and landscape were recorded:
- Habitat loss,
- habitat fragmentation and
- habitat quality loss.
The impact on the appearance of landscape was not examined. Digital 3D aerial photographs were used to determine habitat loss between the 1950s/1960s and 1998/99 in a strip bordering the road and rail infrastructures.
The monetarisation of habitat loss used a repair cost method. Habitat fragmentation was determined using current aerial photographs according to the requirements of different animal groups. The external costs of this fragmentation were calculated using the costs of constructing actual links between the habitat fragments. Habitat quality loss can be identified but not quantified and therefore not monetarised either.
The average external costs for habitat loss and fragmentation are CHF 765 million/year (range: CHF 443-1,083 million/year), CHF 662 million/year of which is caused by road and CHF 103 million/year by rail. The results were compared with existing work and the inaccuracies which may lead to an overestimation or underestimation of the external costs of transport on nature and landscape were indicated.
Assessment of the aerial images enabling a quantitative respectively monetary information on habitat, habitat quality and loss of habitat fragmentation since the 50s.
The information about the loss of habitat fragmentation since the 50s is an important document for further steps in protection of the environment.