Abstract

The spatial distribution of individuals within populations can result in fine-scale density dependence and affect the social environment that is encountered. As such, it is important to quantify within-population spatial structuring and understand the factors that shape it. In this study, we make use of point process statistics to test whether colony size affects the statistical type of spatial nest distribution produced by common terns (Sterna hirundo) breeding at identical manmade rectangular and homogeneous islands of fixed physical size. Comparing subcolonies of variable density both within and across years, we find that inter-nest distances are smaller at higher local and overall breeding density, but that the spatial distribution type does not vary across the observed densities. This suggests that the birds’ main settlement rules do not depend on density. In our case, analyses of fine-scale density dependence or potential social effects therefore do not need to account for between-individual heterogeneity in settlement decision rules or acceptance of these rules. We urge, however, other studies to similarly test for density dependence of the spatial distribution of individuals before undertaking such “downstream” analyses.

中文翻译：

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种群大小影响海鸟的繁殖密度，但不影响空间分布类型

摘要

个体在人口中的空间分布可能导致精细的密度依赖性并影响所遇到的社会环境。因此，量化人口内部空间结构并了解影响其的因素非常重要。在这项研究中，我们利用点过程统计数据来测试菌落的大小是否影响普通燕鸥（Sterna hirundo）产生的空间巢分布的统计类型。）在固定大小的相同人造矩形和均质岛上繁殖。比较多年内和多年内可变密度的亚殖民地，我们发现在较高的局部和整体繁殖密度下，巢间距离较小，但是在所观察到的密度上，空间分布类型没有变化。这表明鸟类的主要定居规则不取决于密度。在我们的案例中，对精细尺度密度依赖性或潜在的社会影响的分析因此无需考虑定居决策规则或这些规则的接受之间的个体异质性。但是，我们敦促其他研究在进行此类“下游”分析之前，同样测试个体对空间分布的密度依赖性。