Effects of land conversion in sub-arctic landscapes on densities of ground-nesting birds

Abstract

Biodiversity is declining globally, primarily driven by anthropogenic changes and alterations of natural habitats. In lowland Iceland, human impact has increased considerably in the past decades, often involving an increase in numbers of anthropogenic structures. The consequences of these land use changes for the important wildlife that these areas support is poorly known. The aim of this thesis was to study if and how four types of newly introduced structures/habitats (roads, summer houses, power lines and plantation forests) in the Icelandic lowlands affect the density and species composition of ground-nesting birds in the surrounding area. Surveys of bird abundance and distribution were undertaken throughout lowland areas of Iceland that varied in the number and extent of anthropogenic structures. Two species (Redwing and Snipe) were found in higher densities or showed no change with distance from the structures, while seven species (Meadow pipit, Black-tailed Godwit, Golden Plover, Dunlin, Oystercatcher, Whimbrel and Redshank) occurred in significantly lower densities close to at least one of these anthropogenic structures and, for roads and forests, these reduced densities occurred over distances up to 200 m. Reduced abundance close to structures was strongest for Golden Plover and Whimbrel, for which between 40-52% of the global populations currently breed in Iceland. The effects of land conversion of large areas of open habitats with roads, forest plantations, houses and power lines could potentially affect populations of these species. Point counts which have been carried out in the southern lowlands since 2011, in an area where anthropogenic influences are constantly expanding, have shown that while the local population of Redwing is increasing and Snipe numbers are stable, the remaining study species are decreasing. Planning of future infrastructure locations and configurations should be designed to reduce impacts on the ground-nesting bird populations for which Iceland has international obligations, and protecting the remaining large tracts of open habitat is likely to be a priority.