Territory selection by the Dartford warbler (Sylvia undata) in Dorset, England : the role of vegetation type, habitat fragmentation and population size

The Dartford warbler (Sylvia undata) is of conservation concern throughout western Europe. In the UK conservation is centred on management of the warbler's lowland heath habitat. This study analysed the warbler's habitat requirements in Dorset, its UK population centre. Maps of breeding territories from 1974, 1984 and 1994 were linked to maps of heathland vegetation and adjacent land use from 1978, 1987 and 1996. Logistic regression showed territories were positively associated with the area of dry/humid heath, mature Ulex europaeus, bare soil, and more rarely with wet heath, young U. europaeus, U. gallii and Pinus scrub. There were negative responses to fragmentation (isolation and area of a heath), and the proximity of woodland, urban areas and intensive agriculture. Sub-optimal habitat was used in years of high population size. Habitat management for this species should consider not only heathland vegetation but also landscape factors such as fragmentation and the proximity of avoided land use types.