The Hazel Grouse (Tetrastes bonasia) is considered an indicator of the naturalness and heterogeneity of the forest environment. This species occurs in various woods and forages on a variety of plants. The aim of this study was to verify the hypothesis that, in Norway spruce-dominated forest stands, the Hazel Grouse compensates for habitat poverty using non-forest areas and harsh topography, which deliver food resources and shelter for the birds. We compared 14 environmental and topographic variables in forest patches occupied and unoccupied by the Hazel Grouse in the Tatra Mountains (South Poland). Multivariate modelling showed that crucial factors for Hazel Grouse occurrence in spruce-dominated high-mountain forests were southern or western exposures, the presence of streams or glades and a multilayer forest structure with lower plant species richness in the undergrowth layer. Moreover, this species avoided clearcuts and depended either on wild sites (with a high share of deadwood and treefall gaps in mature stands at higher altitudes) or juvenile stands. The results of our study confirmed that gaps in forests and diverse topography could compensate the Hazel Grouse for habitat deficiency. These findings may be important for effective protection of this species in high-mountain spruce-only dominated forests.

中文翻译：

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森林栖息的鸟类 Hazel Grouse (Tetrastes bonasia) 的差距和不同的地形能否弥补栖息地的不足？

榛鸡（Tetrastes bonasia）被认为是森林环境自然性和异质性的指标。该物种存在于各种植物的各种树林和草料中。本研究的目的是验证以下假设：在挪威云杉占主导地位的林分中，榛鸡利用非森林地区和恶劣的地形来补偿栖息地贫困，为鸟类提供食物资源和庇护所。我们比较了塔特拉山脉（波兰南部）的榛松鸡占据和未被占据的森林斑块中的 14 个环境和地形变量。多变量模型表明，云杉占主导地位的高山林中榛松鸡发生的关键因素是南部或西部暴露，溪流或林间空地的存在以及灌木层中植物物种丰富度较低的多层森林结构。此外，该物种避免砍伐并依赖于野生场地（在较高海拔的成熟林分中有大量枯木和树木倒塌间隙）或幼林。我们的研究结果证实，森林中的差距和不同的地形可以补偿榛鸡栖息地的不足。这些发现对于在高山云杉为主的森林中有效保护该物种可能很重要。我们的研究结果证实，森林中的差距和不同的地形可以补偿榛鸡栖息地的不足。这些发现对于在高山云杉为主的森林中有效保护该物种可能很重要。我们的研究结果证实，森林中的差距和不同的地形可以补偿榛鸡栖息地的不足。这些发现对于在高山云杉为主的森林中有效保护该物种可能很重要。