Effect of low‐traffic roads on abundance of ground‐nesting birds in sub‐Arctic habitats

Roads are among the most widespread anthropogenic structures, and their presence can impact biodiversity in surrounding landscapes through disturbance and collision risk, particularly when traffic volumes are high. However, the impact of roads with low traffic volumes in open landscapes is much less clear. In the open landscapes of lowland Iceland, road traffic is still relatively low but increasing, and the surrounding landscapes support internationally important populations of several breeding wader species. Here, we used transect counts perpendicular to low‐traffic (≤ 15 000 vehicles day −1 ) roads across the lowlands of southern Iceland to quantify variation in the densities of ground‐nesting birds with distance from roads, and to assess how far from the roads any such effects extended. The total abundance of birds increased significantly by 6% per 50 m interval from roads, and densities within 200 m of roads were ~ 20% lower than densities between 200 and 400 m from roads. Four species – whimbrel Numenius phaeopus , golden plover Pluvialis apricaria , dunlin Calidris alpina and meadow pipit Anthus pratensis – were found in significantly lower densities closer to roads, while four – black‐tailed godwit Limosa limosa , redshank Tringa totanus , snipe Gallinago gallinago and redwing Turdus iliacus – showed no change with distance from roads. Redwing was found in higher densities, and dunlin in lower densities, surrounding roads with higher traffic volumes. As approximately 20% of lowland Iceland is within 200 m of roads, the impact of roads on the overall abundance of ground‐nesting birds could be substantial. The results show that even relatively low‐traffic roads can have a significant impact on adjacent wildlife populations. Road construction, along with other anthropogenic structures, has been shown to have negative effects on bird abundance, and identifying areas for protection from such developments may be the most effective approach to reducing human impacts on the internationally important wildlife of lowland Iceland.