Analysing the road verges as ecological assets - BIodiversity as company

Abstract

Using GIS-analysis in identifying valuable habitats on slopes of Finnish traffic network Certain built up or otherwise strongly modified environments may be significant for preserving species in endangered natural habitats. These habitats may serve as refuges for endangered species – spaces where they can spread back to their natural environments. These compensatory habitats may serve as a complement to natural habitat protection. Road and railway verges, normally being open, well-lighted and regularly mown areas are potential habitats for grassland species adapted to continuous disturbance. Semi-natural grasslands as well as dry exposed esker habitats constitute a threatened, declining habitat type in Northern, and suitable alternative habitats are needed for survival of these populations. In fact, several grassland species do occur in Finnish road and railway corridors. In this study we analyzed habitats along the Finnish highway and railroad system to find the most valuable habitats resembling the endangered esker habitats. Different approaches were used for road and railways and this presentation focuses on the analysis of road slopes. We used geographic information methods to first find the road slopes with ideal exposure, soil quality and slope. Then we used Google Street View to classify the patches identified by the initial GIS-analysis. The classification was done based on vegetation cover, coverage of different vegetation types, and proximity to conservation areas. Method was first tested in pilot areas, of the provinces of Pirkanmaa, Kanta-Häme and Päijät-Häme and then the analysis was then expanded to include the whole Finnish highway (main roads) and railway system. The analysis resulted in 386 sites along road slopes. The total length of the sites were 66 km and the length of the sites varied from 8 to 1 171 m (average 171). The rough estimate of their total area is on average 13,2 hectares which is 1,1 % of the total estimated area of the whole network of known endangered exposed sunny meadow and esker habitats in Finland. There total area of these sites is small in relation to the total area of their natural endangered counterpart habitats. However, these sites may have importance for the survival of the endangered species in dry exposed habitats as a part of their habitat network when: 1. they form a network with valuable natural habitats 2. they form a network of stepping stones or a corridor between valuable natural habitats 3. the compensatory sites themselves form a connected network or a corridor along The results of the analyses give an opportunity to the owner of these land assets the to develop the management of road slopes to promote their biodiversity value.