Comparison of bird communities in stands of introduced lodgepole pine and native Scots pine in Sweden
The introduced lodgepole pine (Pinus contorta) occupies more than 650 000 hectares in Sweden. There are some differences between lodgepole pine and Scots pine (Pinus sylvestris) forests which could affect bird assemblages, for example differences in canopy density and ground vegetation. Birds were surveyed in 14 localities in northern Sweden, each characterized by one middle-aged stand of lodgepole pine next to a stand of Scots pine. The two paired stands in each locality were planted by the forestry company SCA at the same time and in similar environment to evaluate the potential of lodgepole pine in Sweden. In those 14 localities, one to three point count stations were established in both the lodgepole pine and the Scots pine stand, depending on the size of the area. The point count stations had a radius of 50 meters and all birds seen or heard inside that radius (overflying birds excluded) were counted on four visits in late May and June. There were no significant differences in total abundance and species richness between the lodgepole pine and Scots pine stands. A total number of 20 species were counted in Scots pine and 19 species in lodgepole pine. The spotted flycatcher (Muscicapa striata) had a significantly higher abundance in lodgepole pine stands and the chaffinch (Fringilla coelebs) had a nearly significantly higher abundance in the lodgepole pine stands. Two species had a tendency to be more common in the Scots pine forest: the goldcrest (Regulus regulus) and the willow warbler (Phylloscopus trochilus), but the differences were not statistically significant. I conclude that the common species which were recorded in large enough numbers for statistical analyses are probably not negatively affected by lodgepole pine at the stand scale, but further studies would be required to assess the breeding success of sensitive resident birds in lodgepole pine habitats before any definite conclusions can be drawn.