Assessing the influence of resource covariates at multiple spatial scales: an application to forest-dwelling caribou faced with intensive human activity
Assessing the influence of resource covariates at multiple spatial scales: an application to forest-dwelling caribou faced with intensive human activity
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评估多个空间尺度资源协变量的影响：对面临密集人类活动的森林驯鹿的应用
作者：
Mathieu Leblond;Jacqueline L. Frair;D. Fortin;C. Dussault;J. Ouellet;R. Courtois
在隔离资源和干扰对动物分布模式的相对影响的努力仍然受到阻碍，难以占多尺度的资源选择的动物与季节性动态驱动程序。我们开发了多尺度，季节性模型，以探讨当地资源的选择受到威胁的森林居住的林地驯鹿（Rangifer tarandus驯鹿）是由两个大尺度的景观背景和当地资源异质性的影响，在加拿大魁北克省的Charlevoix，位于北美驯鹿范围的南部边界的集中管理区域。我们估计资源选择功能，2004年至2006年监测23个GPS项圈驯鹿和景观数据的植被类，地形条件和道路。我们发现了道路“邻近”效应（最多1.25公里）阈值的证据，这强调了除了当地测量的变量外，还包括景观背景变量的重要性，以及在选择幅度和最佳测量尺度上随时间变化的拟合季节性模型的重要性。开阔的地衣林地是驯鹿在冬季和春季的重要覆盖类型，而落叶林，湿地，甚至年轻的干扰站成为重要的产犊和夏季。驯鹿一贯避免道路和崎岖的地形条件在当地和景观水平。景观背景从根本上限制了动物的选择，我们表明，不考虑景观背景，或任意选择一个不适当的尺度来测量协变量，可能会提供有偏见的推断与栖息地选择模式。对稀有或衰退物种的有效生境管理应仔细考虑生境选择的等级性质。
Efforts in isolating the relative effects of resources and disturbances on animal-distribution patterns remain hindered by the difficulty of accounting for multiple scales of resource selection by animals with seasonally dynamic drivers. We developed multi-scale, seasonal models to explore how local resource selection by the threatened forest-dwelling woodland caribou (Rangifer tarandus caribou) was influenced by both broad-scale landscape context and local resource heterogeneity in the intensively managed region of Charlevoix, Québec, Canada, located on the southern border of the North American caribou range. We estimated resource selection functions using 23 GPS-collared caribou monitored from 2004 to 2006 and landscape data on vegetation classes, terrain conditions, and roads. We found evidence of thresholds in road “proximity” effects (up to 1.25 km), which underscores the importance of including landscape context variables in addition to locally measured variables, and of fitting seasonal-specific models given temporal variation in the magnitude of selection and optimal scale of measurement. Open lichen woodlands were an important cover type for caribou during winter and spring, whereas deciduous forests, wetlands, and even young disturbed stands became important during calving and summer. Caribou consistently avoided roads and rugged terrain conditions at both local and landscape levels. Landscape context fundamentally constrains the choices available to animals, and we showed that failing to consider landscape context, or arbitrarily choosing an inappropriate scale for measuring covariates, may provide biased inferences with respect to habitat selection patterns. Effective habitat management for rare or declining species should carefully consider the hierarchical nature of habitat selection.