Introduction of summer houses into semi-natural habitats: impacts on ground-nesting birds

Degradation of natural and semi-natural habitats is often initiated and facilitated by expansions in anthropogenic infrastructures. Identifying and reducing the impact of anthropogenic structures on the wildlife that these habitats support is vital for biodiversity conservation. In Iceland, the number of summer houses has increased over the past two decades, from similar to 10 000 to 15 000, and >7000 additional plots for summer house construction have been approved. Most of this housing infrastructure development is in the Icelandic lowlands, which support internationally important populations of several ground-nesting bird species. To explore the effects of summer house infrastructure on the distribution of ground-nesting birds, we conducted surveys at 292 points within 71 sites with varying density of houses and associated infrastructure (tracks, decking, etc). Significant reductions in abundance with increasing housing density occurred in five (Golden Plover (Pluvialis apricaria), Black-tailed Godwit (Limosa limosa), Redshank (Tringa totanus), Whimbrel (Numenius phaeopus) and Meadow pipit (Anthus pratensis)) of the seven study species, while one species (Snipe (Gallinago gallinago)) showed no change and one (Redwing (Turdus iliacus)) increased. The differences in abundance between plots with no houses and plots with high house densities (>0.5 houses ha-1) ranged from 34 to 95%, despite the housing infrastructure covering only similar to 6% of the area of these plots. These findings suggest that even relatively low densities of anthropogenic structures in natural or semi-natural areas can have substantial impacts on wildlife in the surrounding areas and highlight the urgent need for effective planning regulations to limit the expansion of anthropogenic structures into currently undisturbed habitats, particularly in areas of high biodiversity value.