The pattern of Dunlin Calidris alpina distribution and abundance in relation to habitat variation in the Flow Country of northern Scotland

• Published in: Bird study 1996-07, Vol.43 (2), p.231-239
• Main Authors: Lavers, C.P., Haines-Young, R.H.
• Format: Article
• Language: English
• Subjects: Calidris; Calidris alpina; Eriophorum; Freshwater; Molinia; Sphagnum; Tricophorum
• ISSN: 0006-3657; 1944-6705
• DOI: 10.1080/00063659609461015

The object of the research reported here was to produce a map of habitat quality for the Dunlin across the Flow Country of northern Scotland for use in conservation and land-use planning. The region is too large (ca. 1800 km 2 ) to survey on foot without significant expenditure of time and resources. Habitat quality was therefore predicted by relating Dunlin density recorded on a set of sample sites in the region to vegetation and landform characteristics. Density was then extrapolated across the whole region based on the recurrence of similar habitat conditions. The abundance of Dunlin in the Flow Country is shown to be related to several different classes of environmental variation. Dunlin are absent from several easily delimited types of habitat (e.g. lochs and woodland). A presence/absence map of habitat quality for the species is achieved simply by mapping these habitat features. Abundance on the moorland that remains is related to vegetation characteristics and the presence of clusters of pools (pool-systems). Dunlin prefer areas of moorland with short, sparse vegetation. However, within such sites, regardless of vegetation type, Dunlin density varies systematically with respect to pool-systems, increasing exponentially as these habitat features are approached. Density variation with respect to changes in vegetation characteristics and pool-systems were modelled to produce a map of habitat quality within a 1 ha grid over the whole region.