State-space models link elk movement patterns to landscape characteristics in Yellowstone National Park
State-space models link elk movement patterns to landscape characteristics in Yellowstone National Park
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DOI：
10.1890/06-0534
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发表时间：
2007-05-01
影响因子：
6.1
通讯作者：
Boyce, Mark S.
中科院分区：
文献类型：
--
作者：
Forester, James D.;Ives, Anthony R.;Boyce, Mark S.
解释和预测异质景观中的动物运动仍然具有挑战性。这在一定程度上是因为移动路径通常包括一系列短暂的局部位移，这些位移被较长距离的突袭所分隔。这种多相运动行为反映了动物对当前环境条件及其内部行为状态的复杂反应。这种状态是一个自相关的过程，受之前的行为和所访问的栖息地的影响。取决于动物行为状态的运动模式代表了动物对环境的广泛反应。量化动物对当地条件和内部状态的反应，揭示了动物在不同空间尺度上对空间异质性的反应。采用状态-空间统计方法，对美国黄石国家公园夏季麋鹿（Cervus elaphus）的内部行为状态和近似运动响应进行了建模，分析了牧草生物量、景观组成、地形和狼（Canis lupus）密度对麋鹿内部行为状态的影响。研究人员对16只雌性麋鹿的运动轨迹进行了分析，这些麋鹿安装了全球定位系统（GPS）无线电项圈，每隔5小时记录一次位置。以每个间隔的起始位置为中心，在175 m半径内（5 h位移中位数的一半）量化生境变量。逐步模型选择确定了最能解释每种动物的运动距离的模型。大多数动物的行为状态变化非常缓慢（中位数自相关r = 0.93），所有动物对一天中的时间反应强烈（黄昏时运动较多）。然而，包含在最佳拟合模型中的空间变量在单个麋鹿之间存在很大差异。这些结果表明，在其他研究中观察到的强烈的栖息地选择模式可能是由于频繁访问首选区域而不是减少在这些区域的活动。
Explaining and predicting animal movement in heterogeneous landscapes remains challenging. This is in part because movement paths often include a series of short, localized displacements separated by longer-distance forays. This multiphasic movement behavior reflects the complex response of an animal to present environmental conditions and to its internal behavioral state. This state is an autocorrelated process influenced by preceding behaviors and habitats visited. Movement patterns depending on the behavioral state of an animal represent the broad-scale response of that animal to the environment. Quantifying how animals respond both to local conditions and to their internal state reveals how animals respond to spatial heterogeneity at different spatial scales. We used a state-space statistical approach to model the internal behavioral state and the proximate movement response of elk (Cervus elaphus) to available forage biomass, landscape composition, topography, and wolf (Canis lupus) density during summer in Yellowstone National Park, USA. We analyzed movement paths of 16 female elk fitted with global positioning system (GPS) radio collars that recorded locations at 5-h intervals. Habitat variables were quantified within 175 m radii (one-half of the median 5-h displacement) centered on the beginning location of each interval. Stepwise model selection identified models that best explained the movement distances of each animal. The behavioral state changed very slowly for most animals (median autocorrelation r = 0.93), and all animals responded strongly to time of day (with more movement in the crepuscular hours). However, the spatial variables included in the best-fitting models varied substantially among individual elk. These results suggest that strong patterns of habitat selection observed in other studies may result from frequent visits to preferred areas rather than a reduction of movement in those areas.