Dispersal without drivers: Intrinsic and extrinsic variables have no impact on movement distances in a terrestrial amphibian

Dispersive movements are often thought to be multicausal and driven by individual body size, sex, conspecific density, environmental variation, personality and/or other variables. Yet such variables often do not account for most of the variation among dispersive movements in nature, leaving open the possibility that dispersion may be indeterministic. We assessed the amount of variation in 24 h movement distances that could be accounted for by potential drivers of displacement with a large empirical dataset of movement distances performed by Fowler’s Toads (Anaxyrus fowleri) on the northern shore of Lake Erie at Long Point, Ontario (2002–2021, incl.). These toads are easy to sample repeatedly, can be identified individually and move parallel to the shoreline as they forage at night, potentially dispersing to new refuge sites. Using a linear mixed-effect model that incorporated random effect terms to account for sampling variance and inter-annual variation, we found that all potential int...

扩散运动（Dispersive movements）通常被认为是多因素驱动的，其影响因素包括个体体型、性别、同种密度、环境变异、个性及其他变量。然而，这些变量往往无法解释自然界中扩散运动的大部分变异，这使得扩散可能具有不确定性的可能性仍然存在。我们利用安大略省朗波因特（Long Point）伊利湖北岸的 Fowler 蟾蜍（Anaxyrus fowleri）在2002年至2021年（含）期间的大量移动距离实证数据集，评估了24小时移动距离变异中可由潜在位移驱动因素解释的比例。这些蟾蜍易于重复采样，可被个体识别，夜间觅食时沿平行于海岸线的方向移动，可能扩散至新的庇护场所。我们使用线性混合效应模型（linear mixed-effect model）（该模型纳入随机效应项以解释采样方差和年际变异），发现所有潜在的内...