We examined the relative importance of competitor abundance and environmental variables in determining the species distributions of 175 bird species across North America. Unlike previous studies, which tend to model distributions in terms of presence and absence, we take advantage of a geographically extensive dataset of community time series to model the temporal occupancy of species at sites throughout their expected range.

中文翻译：

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生物和非生物时间决定因素在北美鸟类中的相对重要性

我们研究了竞争者数量和环境变量在确定北美175种鸟类的物种分布中的相对重要性。与以前的研究倾向于根据存在和不存在来对分布进行建模不同，我们利用社区时间序列的地理上广泛的数据集来对物种在整个预期范围内的时间占用情况进行建模。