Growth rate island dataset from The effect of insularity on avian growth rates and implications for insular body size evolution

Island populations often differ in consistent ways from their mainland counterparts with respect to their ecology, behaviour, morphology, demography and life-history characteristics; a set of changes referred to as the ‘island syndrome’. To understand the ecological and evolutionary drivers of the island syndrome requires characterization of suites of interacting traits. While patterns in some types of traits, e.g. body size, are well characterized across a range of taxa, key gaps remain. Growth rate is one such trait, being an important determinant of both increases and decreases in body size, and can vary with changes in predation pressure and food limitation; two factors that are known to differ between mainland and island environments. Using a phylogenetic meta-analytic approach, we characterize differences in growth rates among mainland and island altricial bird populations, controlling for environmental factors. We found a trend towards slower growth on islands in small-bodied (less than 1 kg) bird species. This is consistent with the idea that the pattern of body size increases in small-bodied island colonists is associated with the evolution of slower growth combined with shifts in age and size at maturity in relaxed predation regimes.岛屿种群在生态学、行为学、形态学、种群统计学以及生活史特征等维度上，往往与大陆同源种群存在稳定差异；这一系列适应性变化被统称为“岛屿综合征（island syndrome）”。要解析岛屿综合征的生态与进化驱动机制，需对一系列互作性状开展系统表征。尽管诸如体型这类性状的分布模式已在多个生物类群中得到充分刻画，但该领域仍存在关键研究空白。生长速率正是这类有待深入探究的性状之一：它既是体型增减的核心调控因子，同时也会随捕食压力与食物限制的变化而改变——而这两类环境因子在大陆与岛屿生境中普遍存在显著差异。本研究采用系统发育元分析方法（phylogenetic meta-analytic approach），在控制环境变量的前提下，对比了晚成鸟（altricial bird）大陆种群与岛屿种群的生长速率差异。研究发现，在体型小于1千克的鸟类类群中，岛屿种群的生长速率呈现出普遍减慢的趋势。该结果与下述假说一致：在捕食压力放松的生境中，小型岛屿拓殖种群的体型增大模式，与生长速率减慢以及成熟年龄、成熟体型的适应性演化存在关联。