Long-term variations in waterfowl populations in Loch Leven: identifying discontinuities between local and national trends

Loch Leven has been designated as a UK Ramsar Site (1976), a Site of Special Scientific Interest (1985) and a Special Protection Area (2000) due to its importance as a site for overwintering waterfowl. However, no comprehensive assessment of trends in waterfowl at the local versus national scale has been conducted at the site. Coherence between trends in 5-year mean species abundance for Loch Leven and Underhill Indexing Method values for Scotland (or GB in the case of geese) were assessed using principal components analysis for ten study species between 1968 and 2006. Five species showed trends at Loch Leven that were coherent with those at the Scottish scale (Eurasian Teal, Mute Swan, Great Cormorant, Pink-footed and Greylag geese). These species may not respond positively to local scale management. However, the other five species (Mallard, Coot, Great Crested Grebe, Tufted Duck and Pochard) showed distinct differences between local and national trends. A study of the feeding ecology for these species, the re-establishment of ringing effort and an assessment of waterfowl–wetland relationships are recommended to determine how changes in local food resources and habitat quality interact with macro-scale population dynamics to influence local and regional patterns of abundance.