Linear infrastructure habitats, such as power line corridors, road verges and railways often resemble species rich semi-natural grasslands, are recurring and cover vast areas. Despite of this, it is not known how these linear habitats contribute to biodiversity and ecosystem services in the landscape. Research suggests that in spite of the well documented negative effects on biodiversity of linear infrastructure (e.g. mortality by collisions with traffic, spread of invasive species or introduction of barriers for dispersal), these habitats are potentially valuable for conservation. Their potential to support a high diversity of species could, however, be dependent on the context of the landscape. We established a study design comprising 32 landscapes in Sweden with contrasting amount of power line corridors and road verges to determine the relative contribution of these linear infrastructure habitats to landscape biodiversity and the overall effect of area of these habitat types. All landscapes were dominated by forest, with some arable fields and grasslands. In 2016, we sampled plant, butterfly and bumblebee communities within these landscapes in a subset of patches of prevalent types of grasslands (semi-natural pastures, uncultivated field borders), and in the infrastructure habitats (road verges and power-line corridors). We investigated whether the contribution to biodiversity at the landscape scale by road verges and power-line corridors depends on the total amount and quality of grasslands in the landscape. We considered species richness, the evenness of the communities and their phylogenetic diversity. We predicted power line corridors and road verges to have a positive relationship to all of the above mentioned measures of biodiversity at the landscape scale. This is because of a general increase in habitat area at the landscape level for plants and pollinators, and because different habitats may provide the landscape with a different set of species. Our first analyses show that despite of not having an overall positive effect on all three groups of species, the interaction of road verges with other habitat elements in the landscape was often beneficial for the diversity of plants and pollinators. Road verges mitigate the negative effects of land-use change on the number of butterfly species in the landscape, and in combination with power line corridors increase the evenness of plant communities. On the other hand, power line corridors had a clear positive effect on the number of plant species in the landscape, which is in turn beneficial to all organisms that depend on them for their persistence. It is important to take the composition of the landscape into account when evaluating the value of linear infrastructure habitats for biodiversity.