Effects of forest management on Three-toed Woodpecker Picoides tridactylusdistribution in the Białowieża Forest (NE Poland): conservation implications
Abstract:Distribution of Three-toed Woodpeckers and that of dead wood were mapped in two fragments of the Białowieża National Park (BNP) differing in their management history — primeval (old-growth stands of natural origin, no human intervention) and logged (as the former but subject to 80 years of commercial forestry). Data were collected during the breeding seasons 1999–2001. In the end of April 2000, the whole BNP was systematically searched; playbacks of drumming were used to enhance detection of birds. Presence/absence of Three-toed Woodpeckers and of dead wood (standing and downed Norway spruces and snags of other trees) were recorded within each forest sub-compartments (ca. 28 ha). Data from censuses done in smaller plots in 1975–1999 showed that in the primeval forest the woodpeckers bred twice more frequently in swampy and coniferous forests than in the oak-hornbeam habitat. These preferred habitat types covered larger areas in the logged fragment than in the primeval part (66% vs. 41%). Yet despite this, Three-toed Woodpeckers were recorded there over twice less frequently (14% of 176 sub-compartments) than in the primeval (36% of 164 sub-compartments) part. These differences followed sharp contrasts in the dead wood availability; all but one sub-compartments in the primeval fragment contained some form of dead wood, whereas dead spruces were missing in almost 30% of sub-compartments in the logged part. This was the effect of continuous "sanitary" logging, purposeful removal of dying and dead spruces from the Forest. To restore Three-toed Woodpecker habitats it is necessary to ban removal of dead spruces in the managed part of BNP. However, the BNP area is too small, to assure the long-term survival of the Białowieża Forest population. To achieve this, it is necessary to resign from removal of dying and dead spruces in the whole Polish part of the Białowieża Forest (600 km2). This would create breeding habitat for a maximum 260–320 pairs.
Document Type: Research Article
Publication date: June 1, 2005