Abstract:
The home-range concept is central in animal ecology and behavior, and numerous mechanistic models have been developed to understand home range formation and maintenance. These mechanistic models usually assume a single, contiguous home range. Here we describe and implement a simple home-range model that can accommodate multiple home-range centers, form complex shapes, allow discontinuities in use patterns, and infer how external and internal variables affect movement and use patterns. The model assumes individuals associate with two or more home-range centers and move among them with some estimable probability. Movement in and around home-range centers is governed by a two-dimensional Ornstein-Uhlenbeck process, while transitions between centers are modeled as a stochastic state-switching process. We augmented this base model by introducing environmental and demographic covariates that modify transition probabilities between home-range centers and can be estimated to provide insight into the movement process. We demonstrate the model using telemetry data from sea otters (Enhydra lutris) in California. The model was fit using a Bayesian Markov Chain Monte Carlo method, which estimated transition probabilities, as well as unique Ornstein-Uhlenbeck diffusion and centralizing tendency parameters. Estimated parameters could then be used to simulate movement and space use that was virtually indistinguishable from real data. We used Deviance Information Criterion (DIC) scores to assess model fit and determined that both wind and reproductive status were predictive of transitions between home-range centers. Females were less likely to move between home-range centers on windy days, less likely to move between centers when tending pups, and much more likely to move between centers just after weaning a pup. These tendencies are predicted by theoretical movement rules but were not previously known and show that our model can extract meaningful behavioral insight from complex movement data.
摘要:
家庭范围概念是动物生态学和行为的核心,并且已经开发了许多机械模型来了解家庭范围的形成和维护。这些机械模型通常假设一个单一的,连续的家庭范围。在这里,我们描述和实现一个简单的家庭范围模型,可以容纳多个家庭范围中心,形成复杂的形状,允许使用模式中的不连续性,并推断外部和内部变量如何影响运动和使用模式。该模型假设个人与两个或多个家庭中心相关联,并以某种可估计的概率在其中移动。家庭牧场中心及其周围的运动受二维Ornstein-Uhlenbeck过程的支配,而中心之间的转换被建模为随机状态切换过程。我们通过引入环境和人口统计学协变量来扩展此基础模型,这些协变量可以修改家庭范围中心之间的过渡概率,并且可以进行估计以提供对运动过程的了解。我们使用来自加利福尼亚州海獭(Enhydralutris)的遥测数据演示了该模型。使用贝叶斯马尔可夫链蒙特卡罗方法对模型进行拟合,估计转移概率,以及独特的Ornstein-Uhlenbeck扩散和集中趋势参数。然后,可以使用估计的参数来模拟与实际数据几乎无法区分的运动和空间使用。我们使用偏差信息标准(DIC)评分来评估模型拟合度,并确定风和生殖状态都可以预测家庭牧场中心之间的过渡。在大风天,女性不太可能在家庭中心之间移动,抚育幼犬时不太可能在中心之间移动,更有可能在小狗断奶后在中心之间移动。这些趋势是通过理论运动规则预测的,但以前未知,表明我们的模型可以从复杂的运动数据中提取有意义的行为洞察力。