Conservation Ecology Center, Smithsonian Conservation Biology Institute, Front Royal, VA, USA
Conservation Ecology Center, Smithsonian Conservation Biology Institute, Front Royal, VA, USA.
Philos Trans R Soc Lond B Biol Sci. 2018 May 19;373(1746). doi: 10.1098/rstb.2017.0007.
While many animal species exhibit strong conspecific interactions, movement analyses of wildlife tracking datasets still largely focus on single individuals. Multi-individual wildlife tracking studies provide new opportunities to explore how individuals move relative to one another, but such datasets are frequently too sparse for the detailed, acceleration-based analytical methods typically employed in collective motion studies. Here, we address the methodological gap between wildlife tracking data and collective motion by developing a general method for quantifying movement correlation from sparsely sampled data. Unlike most existing techniques for studying the non-independence of individual movements with wildlife tracking data, our approach is derived from an analytically tractable stochastic model of correlated movement. Our approach partitions correlation into a deterministic tendency to move in the same direction termed 'drift correlation' and a stochastic component called 'diffusive correlation'. These components suggest the mechanisms that coordinate movements, with drift correlation indicating external influences, and diffusive correlation pointing to social interactions. We use two case studies to highlight the ability of our approach both to quantify correlated movements in tracking data and to suggest the mechanisms that generate the correlation. First, we use an abrupt change in movement correlation to pinpoint the onset of spring migration in barren-ground caribou. Second, we show how spatial proximity mediates intermittently correlated movements among khulans in the Gobi desert. We conclude by discussing the linkages of our approach to the theory of collective motion.This article is part of the theme issue 'Collective movement ecology'.
虽然许多动物物种表现出强烈的同种个体相互作用,但野生动物追踪数据集的运动分析仍然主要集中在单个个体上。多个体野生动物追踪研究为探索个体之间的相对运动提供了新的机会,但此类数据集通常过于稀疏,无法使用集体运动研究中常用的基于加速度的详细分析方法。在这里,我们通过开发一种从稀疏采样数据中定量运动相关性的通用方法来解决野生动物追踪数据和集体运动之间的方法学差距。与大多数现有的用于研究野生动物追踪数据中个体运动非独立性的技术不同,我们的方法源自相关运动的可分析处理随机模型。我们的方法将相关性划分为称为“漂移相关性”的确定的同向运动趋势和称为“扩散相关性”的随机成分。这些成分表明了协调运动的机制,其中漂移相关性指示外部影响,扩散相关性则指向社会相互作用。我们使用两个案例研究来强调我们的方法在量化追踪数据中的相关运动以及提出产生相关性的机制方面的能力。首先,我们利用运动相关性的突然变化来确定荒地驯鹿春季迁徙的开始。其次,我们展示了戈壁沙漠中的野驴如何通过空间接近度来调节间歇性相关的运动。最后,我们讨论了我们的方法与集体运动理论的联系。本文是主题为“集体运动生态学”的一部分。