Landscape-scale effects of Christmas-tree plantations in an intensively used low-mountain landscape - Applying breeding bird assemblages as indicators

The high species richness of threatened breeding bird species in Christmas-tree plantation landscapes was driven mainly by high landscape heterogeneity. Densities of the threatened indicator species of the Christmas-tree plantation landscapes were probably promoted by (i) high availability of suitable food (arthropods, seeds) and (ii) high accessibility to the food resources due to bare ground (tree pipit [Anthus trivialis], woodlark [Lullula arborea]) or low-growing vegetation (linnet [Carduelis cannabina], yellowhammer [Emberiza citronella]) in the Christmas-tree plantations. For the woodlark, Christmas-tree plantations are even among the most important strongholds in the German Federal State of North Rhine-Westphalia.