The distributions of many species are not at equilibrium with their environment. This includes spreading non-native species and species undergoing range shifts in response to climate change. The habitat associations of these species may change during range expansion as less favourable climatic conditions at expanding range margins constrain species to use only the most favourable habitats, violating the species distribution model assumption of stationarity. Alternatively, changes in habitat associations could result from density-dependent habitat selection; at range margins, population densities are initially low so species can exhibit density-independent selection of the most favourable habitats, while in the range core, where population densities are higher, species spread into less favourable habitat. We investigate if the habitat preferences of the non-native common waxbill Estrilda astrild changed as they spread in three directions (north, east and south-east) in the Iberian Peninsula. There are different degrees of climatic suitability and colonization speed across range expansion axes, allowing us to separate the effects of climate from residence time. In contrast to previous studies we find a stronger effect of residence time than climate in influencing the prevalence of common waxbills. As well as a strong additive effect of residence time, there were some changes in habitat associations, which were consistent with density-dependent habitat selection. The combination of broader habitat associations and higher prevalence in areas that have been colonised for longer means that species distribution models constructed early in the invasion process are likely to underestimate species' potential distribution.

中文翻译：

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范围扩大期间栖息地协会的变化：消除气候和停留时间的影响。

许多物种的分布与其环境不平衡。这包括传播非本地物种和响应气候变化而经历范围变化的物种。这些物种的栖息地协会可能会在范围扩展过程中发生变化，因为范围扩展范围边缘处的不利气候条件限制了物种仅使用最有利的栖息地，这违反了物种分布模型的平稳性假设。另外，栖息地协会的变化可能是由密度依赖性的栖息地选择引起的。在范围边缘，种群密度最初较低，因此物种可以表现出与密度无关的最有利的栖息地选择，而在种群密度较高的范围核心，物种则扩散到不利的栖息地。我们调查了非本地普通犀鸟Estrilda astrild在伊比利亚半岛沿三个方向（北，东和东南）传播时，其栖息地偏好是否发生了变化。在范围扩展轴上，气候适应度和定居速度存在不同程度，这使我们能够将气候影响与停留时间区分开。与以前的研究相比，我们发现停留时间比气候对普通蜡嘴鸟流行的影响更大。除了停留时间的强加和效应外，栖息地关联也发生了一些变化，这与密度依赖的栖息地选择是一致的。