Individual variation changes dispersal distance and area requirements of a checkerspot butterfly.
Individual variation changes dispersal distance and area requirements of a checkerspot butterfly.
复制标题
个体差异会改变棋盘蝴蝶的分散距离和面积要求。
作者：
Leone M. Brown;E. Crone
移动的个体差异可能对空间种群动态产生重要影响。例如，个体变异增加了扩散距离的尖峰，使得更多的个体相对于同质种群移动非常短和非常长的距离。我们量化了个体差异的运动的巴尔的摩棋盘斑蝶（Euphydryas phaeton）调查其重要性的两个保护相关的指标：预期的传播距离和临界最小补丁大小，或最小的区域内，人口可以持续的损失，由于移民。所有的运动参数均表现出个体间的差异，其中运动长度和休息时间的差异最大。个体运动参数的相关性表明，一些蝴蝶一般比其他蝴蝶更移动的。我们将经验估计的运动和人口统计参数纳入两个基于个人的模型（IBM），一个是个人之间的运动同质性，另一个是运动异质性。正如预期的那样，运动中的个体差异增加了终生运动距离的尖峰值;运动距离的最大差异很大（-850 m vs.-5800 m），可能对保护具有重要意义。个体差异也影响了临界最小斑块大小，但差异（-0.7公顷对-0.5公顷）不太可能具有生态意义。值得注意的是，个体变异的人口有较高的增长率在小补丁和较低的增长率在大补丁，一个合乎逻辑的结果增加leptokurtosis。运动中的个体变异使用混合效应模型进行量化是相当简单的，并且对于空间种群动态非常重要，因此我们鼓励将其纳入其他系统的研究中。
Individual variation in movement can have important consequences for spatial population dynamics. For instance, individual variation increases leptokurtosis in dispersal distance, such that more individuals move very short and very long distances relative to a homogeneous population. We quantified individual variation in movement of the Baltimore checkerspot butterfly (Euphydryas phaeton) to investigate its importance for two conservation-related metrics: the expected dispersal distance and the critical minimum patch size, or the smallest area within which a population can persist based on loss due to emigration. All movement parameters showed among-individual variation, with the greatest variation in move lengths and time spent resting. Correlations in among-individual movement parameters indicated that some butterflies were generally more mobile than others. We incorporated empirically estimated movement and demographic parameters into two individual-based models (IBMs), one with homogeneity in movement among individuals, and one with heterogeneity in movement. As expected, individual variation in movement increased the leptokurtosis of lifetime movement distance; the maximum difference in distance moved was substantial (-850 m vs. -5800 m) and is likely of significance for conservation. Individual variation also affected the critical minimum patch size, but the difference (-0.7 ha vs. -0.5 ha) is unlikely to be ecologically significant. Notably, populations with individual variation had higher growth rates in small patches and lower growth rates in large patches, a logical consequence of increased leptokurtosis. Individual variation in movement is fairly straightforward to quantify using mixed effects models and is important for spatial population dynamics, thus we encourage its inclusion in studies of other systems.