Viau Julie-Pier, Sigouin Daniel, St-Laurent Martin-Hugues
Centre for Forest Research, Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, 300 allée des Ursulines, Rimouski, QC G5L 3A1, Canada.
Parks Canada, Forillon National Park, 1501 boul. Forillon, Gaspé, QC G4X 6M1, Canada.
J Mammal. 2024 May 7;105(4):740-751. doi: 10.1093/jmammal/gyae048. eCollection 2024 Aug.
Old-growth forests harbor a large amount of complex structural features that result in a wide array of wildlife habitats. However, intensive forest management is gradually converting old-growth forest into younger, even-aged stands, reducing structural complexity and threatening the persistence of old-growth-dependent species. Maintaining elements of complex stand structure is critical to the conservation of old-growth forest specialists that use different habitat components at different periods of their annual cycle, and it requires a comprehensive understanding of seasonal variation in the habitat needs of these species. However, difficulties in observing free-ranging animals have sometimes limited our ability to assess such variations in habitat requirements, especially for small, elusive species. To address this, we used GPS telemetry collars to describe fine-scale habitat selection patterns of 6 male American Martens () during 2 contrasting periods of the year (snow-free, from mid-April to mid-November; snow-covered, from mid-November to mid-April), an objective formerly hard to achieve using conventional VHF telemetry. We used resource selection functions conducted at the fourth order of selection to compare habitat characteristics found at the sites used by martens (GPS locations, = 100) to those found on an equal number of available sites (random points, = 100) within each individual seasonal home range. We conducted vegetation surveys on these 200 sites to describe habitat and built candidate models representing different concurrent hypotheses. Our results showed that proxies of prey availability, predator avoidance, and thermal constraints were the primary factors influencing marten habitat selection during both periods, although their respective importance differed between periods. Martens selected sites with a high density of large-diameter snags (≥30·ha), high conifer canopy closure (≥53%), and a dense lateral cover (≥81%) during the snow-free period, but selected sites with a high volume of coarse woody debris (≥64 m·ha) and high conifer canopy closure (≥48%) during the snow-covered period. Our results highlight the importance of contrasting seasonal changes in habitat selection patterns of small carnivores and may help maintain structural attributes in the landscape that are suitable for male American Martens.
原始森林拥有大量复杂的结构特征，从而形成了各种各样的野生动物栖息地。然而，高强度的森林管理正逐渐将原始森林转变为更年轻的同龄林分，降低了结构复杂性，并威胁到依赖原始森林生存的物种的延续。维持复杂林分结构的要素对于保护那些在其年度周期的不同时期利用不同栖息地组成部分的原始森林特有物种至关重要，这需要全面了解这些物种栖息地需求的季节性变化。然而，观察自由活动动物的困难有时限制了我们评估栖息地需求这种变化的能力，尤其是对于小型、难以捉摸的物种。为了解决这个问题，我们使用全球定位系统遥测项圈来描述6只雄性美洲貂在一年中两个对比时期（无雪期，从4月中旬到11月中旬；积雪期，从11月中旬到4月中旬）的精细尺度栖息地选择模式，这一目标以前使用传统甚高频遥测很难实现。我们使用在选择的第四个层次上进行的资源选择函数，将貂所使用的地点（全球定位系统位置，n = 100）的栖息地特征与每个个体季节性家域内数量相等的可用地点（随机点，n = 100）的栖息地特征进行比较。我们在这200个地点进行了植被调查以描述栖息地，并构建了代表不同同时存在假设的候选模型。我们的结果表明，猎物可获得性、躲避捕食者和热限制的指标是两个时期影响貂栖息地选择的主要因素，尽管它们各自的重要性在不同时期有所不同。在无雪期，貂选择大直径残干密度高（≥30·公顷）、针叶树冠郁闭度高（≥53%）和侧向覆盖茂密（≥81%）的地点，但在积雪期选择粗木质残体体积大（≥64立方米·公顷）和针叶树冠郁闭度高（≥48%）的地点。我们的结果突出了小型食肉动物栖息地选择模式中对比季节性变化的重要性，并可能有助于维持景观中适合雄性美洲貂的结构属性。
