Habitat niche of the Crested Tit Lophophanes cristatus in central and peripheral parts of its range

Abstract

Narrower habitat niche at the range margin may reduce the ability of specialized species to adapt to the changing environments and to shift the range. In most of its European range, the Crested Tit (Lophophanes cristatus) inhabits pine forests throughout the year; those forests are important timber production areas for forest industries. We studied the breeding distribution of this species in relation to forest characteristics in (i) the central part of the range in Estonia, where pine areas have undergone large transformations because of peatland drainage for forestry, and (ii) in isolated populations at the southern range margin in East Ukraine, where historical pine forest losses have been substituted with replanting. In Estonia, both the range of forest site types available and occupied by the species was wider than in Ukraine; the birds occupied forests starting from a younger age and reached higher population densities. A preference for natural mature pine stands was found only in the most peripheral and isolated populations in Ukraine. Larger areas of pine forests in Estonia and their higher historical connectivity may be an important factor that has allowed (large) local populations to adapt to the extensive recent transformations in these ecosystems. In contrast, the historical bottlenecks and isolation of suitable forest patches still limit the population in eastern Ukraine, and climatic, economic, and war-related pressures to pine forests are likely to expose these marginal populations to new fluctuations.