Ardea Official journal of the Netherlands Ornithologists' Union |
Salek M. & Smilauer P. (2002) Predation on Northern Lapwing Vanellus vanellus nests: The effect of population density and spatial distribution of nests. ARDEA 90 (1): 51-60 |
The effects of population density, nest pattern, size of nest aggregations and position of nests within aggregations on predation rates were analysed in two Northern Lapwing Vanellus vanellus populations in agricultural land 1988-98. Two sites (Arable Landscape in South Bohemia Czech Republic, 1988 and Meadow) differed in breeding densities but their nest patterns were similarly clumped. While population density negatively correlated with nest predation rate at both sites, the nest pattern demonstrated only a weak effect. Nest predation was not influenced by distance to the nearest neighbouring nest while it was significantly affected by aggregation size in Meadow but not in Arable Land. Decreasing predation from edge to centre of large aggregations supports Lack's protective umbrella hypothesis. However, large aggregations in Arable Land experienced high predation risk, particularly due to extensive loss of marginal nests indicating that the Northern Lapwings' aggregating behaviour may not always reduce predation risk in the group as a whole. Habitat quality and composition of predator guilds are considered to be factors influencing the different predation pattern on nests at the studied sites |