Hazel grouse habitat requirements are relatively well known in coniferous forests, and less known in mixed or deciduous forests. We studied habitat differences between sites occupied by hazel grouse Tetrastes bonasia and control plots in mixed mountain forests of the Western Carpathians in 2009 and 2010. Hazel grouse presence at sites was determined in April and May. The habitat variables (n = 21) and the proportion of tree and shrub species (n = 22) were collected both in sites of hazel grouse presence and control plots within a radius of 100 m. Greater numbers of tree species and greater proportions of deciduous trees (mainly birch Betula sp.) were found in sites where hazel grouse was present. Lower canopy cover was an important variable for hazel grouse occurrence, and sites with hazel grouse had a greater proportion of young trees (< 40 years). Sites were also characterized by a higher proportion of overgrown glades and dead woods in comparison with control plots. Sites occupied by hazel grouse were characterized by a greater number of tree species in the undergrowth (minimum of five species) in comparison with control plots. GLM models revealed that the most important environmental factors for hazel grouse occurrence in mixed mountain forests were open habitats (overgrown glades), good hiding opportunities (fallen trees and dead woods) and good conditions for foraging (trees cover in undergrowth). Poplar (Populus sp.) and willow (Salix sp.) were the most important tree species for hazel grouse occurrence. The presence of habitat structures and the vegetations richness provides good shelter or food for the hazel grouse. Extensive forest management should be proposed to increase the number of hazel grouse. Large areas covered by herbs and light-seeded tree species of low economical value for forestry are recommended to support hazel grouse population.

中文翻译：

---

栖息地多样性和植物物种丰富度对西喀尔巴阡山混交林中榛鸡发生的重要性

榛鸡栖息地要求在针叶林中相对为人所知，而在混交林或落叶林中则鲜为人知。我们研究了 2009 年和 2010 年西喀尔巴阡山脉混合山林中榛松鸡 Tetrastes bonasia 和对照样地之间的栖息地差异。在 4 月和 5 月确定了这些地点的榛鸡存在。栖息地变量 (n = 21) 以及乔木和灌木物种的比例 (n = 22) 在 100 m 半径内的榛松鸡存在地点和控制地块中收集。在存在榛鸡的地点发现了更多的树种和更大比例的落叶树（主要是桦木 Betula sp.）。较低的树冠覆盖是榛鸡发生的一个重要变量，有榛鸡的地点有更大比例的幼树（< 40 年）。与对照地块相比，这些地点的特征还在于杂草丛生的林间空地和枯木的比例更高。与对照地块相比，榛鸡占据的地点的特点是灌木丛中的树种数量较多（最少 5 种）。GLM 模型显示，混合山林中榛鸡发生的最重要环境​​因素是开阔的栖息地（杂草丛生的林间空地）、良好的藏身机会（倒下的树木和枯木）和良好的觅食条件（灌木丛中的树木覆盖）。杨树 (Populus sp.) 和柳树 (Salix sp.) 是榛鸡发生的最重要树种。栖息地结构的存在和丰富的植被为榛鸡提供了良好的庇护所或食物。应建议粗放森林管理以增加榛鸡的数量。建议在林业经济价值低的草本植物和轻种树种覆盖的大片区域内支持榛鸡种群。