Estimating asymptotic body size and testing geographic variation in Agama impalearis
Estimating asymptotic body size and testing geographic variation in Agama impalearis
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DOI：
10.1111/j.1600-0587.1999.tb00503.x
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发表时间：
1999-06-01
期刊：
影响因子：
5.9
通讯作者：
Harris, P
中科院分区：
文献类型：
--
作者：
Brown, RP;Znari, M;Harris, P
估计“典型的”渐近体大小的方法，在人口中的北非agamid Agama impalearis使用个人的年龄未定的调查，和地理变化的模式，这一特点的描述和测试对简单的模型的基础上假定的原因。一个大型的单中心数据集的恢复表明，使用样本平均值导致大幅低估的渐近大小，而使用最大的动物每个样本导致高估，平均。第80百分位数提供了最准确的估计渐近大小，与每个样本的最大个体相比，具有低方差，对样本量的依赖性较低，并且适合于自举估计置信区间。在摩洛哥各地，渐近大小的地理变化模式很明显：动物在北部和东部最小，在西南部最大。这种模式是不一致的，与先前描述的模式的变化，缩放和大小自由的身体尺寸，不像这些特点，不能解释的模型的基础上，以前的vicariant人口的二次接触。站点之间的分化是密切相关的一个模型的基础上代理目前潜在的基因流之间的网站，支持替代原位分化假说的基础上的综合影响隔离的距离和分散的障碍提供的较高部分的阿特拉斯山脉。可能的原因之间的不一致的变化模式，在身体大小和其他形态特征进行了讨论。
Methods for estimating 'typical' asymptotic body size in populations of the North African agamid Agama impalearis is using individuals of undetermined age were investigated, and the pattern of geographic variation in this characteristic described and tested against simple models based on putative causes. Resampling of a large single-site data set indicated that use of the sample mean led to substantial underestimation of asymptotic size while use of the largest animal per sample led to overestimation, on average. The 80th percentile provided the most accurate estimate of asymptotic size and, compared with the largest individual per sample, had low variance, showed low dependence on sample size and was amenable to bootstrap estimation of confidence intervals. A clear pattern of geographic variation in asymptotic size was evident across Morocco: animals were smallest in the north and east and largest in the southwest. This pattern was discordant with previously-described patterns of variation in scalation and size-free body dimensions and, unlike these characteristics, could not be explained by a model based on secondary contact of previously vicariant populations. Among-site differentiation was strongly associated with a model based on a proxy of current potential gene flow between sites, supporting an alternative in situ differentiation hypothesis based on the combined effects of isolation-by-distance and the dispersal barrier provided by the higher parts of the Atlas mountain range. Possible reasons for the discordance between the pattern of variation in body size and other morphological characteristics are discussed.