Data for: Effect of low-traffic roads on abundance of ground-nesting birds in sub-Arctic habitats

Roads are one of the most widespread anthropogenic structures, and their
presence can impact biodiversity in the 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) roads across the lowlands of southern
Iceland, to quantify variation in densities of ground-nesting birds with
distance from roads and 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 to roads. Redwing
was found in higher densities and Dunlin in lower densities surrounding
roads with higher traffic volume. 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 reduce human impacts on the internationally
important wildlife of lowland Iceland.